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Emergency Landing the Result of Flawed Maintenance & Poor Cockpit Procedures

Mon, Apr 20, 2009 — David Evans

Articles, Featured

It was the seemingly never-ending emergency, even after the airplane was safely on the ground. All told, the engine fire, hasty landing, dousing of the fire by airport firefighters, spilled fuel, reapplication of fire extinguishing agent, and passenger evacuation took about an hour and five minutes.

Fire damage to the left engine, including massive hole in bottom of cowling with wires burnt and dangling out.

Fire damage to the left engine, including massive hole in bottom of cowling with wires burnt and dangling out.

 

No one on American Airlines Flight 1400, an MD-80 twin jet with 143 passengers and crew aboard, was hurt in the emergency landing 28 September 2007 at St. Louis International Airport, where the airplane had taken off just moments before. However, the accident had profound lessons for the safety of operations. According to National Transportation Safety Board (NTSB) Acting Chairman Mark Rosenker, “Unfortunately, the lack of adherence to procedures led to many of the crew’s in-flight challenges.”

The failure to stick to specified procedures began days before, on the ground.

The affected engine failed to start at least three times in the days before the accident, prompting manual start procedures to be carried out in concert with mechanics. Instead of simply depressing the button on the air turbine starter valve (mounted next to the engine) mechanics depressed the button with a wrench or metal bar. This was an unapproved, ad hoc procedure, widely used by mechanics but not authorized in maintenance manuals for good reason. This unapproved method may have protected mechanics fingers from the heat of the button, but it bent the inner manual override pin inside. This basically meant that when the engines went to takeoff power, the 90 psi hot gas torched through the air turbine starter valve (ATSV), causing it to fail catastrophically – leading to the engine fire and cascading damage to a host of components that led to what might best be called a “compound emergency.”

The button had to be pushed up to allow 30 psi airflow for the manual start, but mechanics used a metal lever to avoid burning their fingers. The use of the metal tool bent the pin, which enabled 90 psi air from the engine at takeoff power to blow past the valve. This destroyed it and started the in-flight engine fire.

The button had to be pushed up to allow 30 psi airflow for the manual start, but mechanics used a metal lever to avoid burning their fingers. The use of the metal tool bent the pin, which enabled 90 psi air from the engine at takeoff power to blow past the valve. This destroyed it and started the in-flight engine fire.

The maintenance history of the ATSV in the days before the accident is revealing:

• ATSV replaced six times in twelve days.

• Twice placed back in service.

• Four times deferred and put on MEL (Minimum Equipment List).

• Three times MEL cleared.

And all the above occurred without any fixing of the basic problem – the bent pin that allowed hot gas to vent past an improperly seated float pin.

Perplexed mechanics fixated and focused on the wiring for the starter assembly, addressing that not once but three times, yet without identifying or fixing the real problem. These repeated, ineffective actions were not recognized or uncovered by the airline’s Continuing Analysis and Surveillance System (CASS).

“The airline’s own internal maintenance system, the purpose of which is to catch maintenance and mechanical issues that could lead to an incident or accident, failed to do what it was designed to do,” said Rosenker. “And that [deficiency] allowed this sequence of events to get rolling, which ultimately resulted in the accident. Following the appropriate maintenance procedures would have gone a long way toward preventing this accident.”

As a result, the NTSB issued the following recommendation to American Airlines:

“Evaluate your Continuing Analysis and Surveillance System program to determine why it failed to (1) identify deficiencies in its maintenance program associated with the MD-80 engine no-start failure and (2) discover the lack of compliance with company procedures. Then, make necessary modifications to the program to correct these shortcomings.”

We’ve seen this problem with CASS before at other carriers. In the wake of the fatal crash 31 January 2000 of Alaska Airlines Flight 261, an MD-80, the Federal Aviation Administration (FAA) in June of that year sent the carrier a letter demanding immediate improvement to maintenance practices and management or face fleet wide grounding.

This action was taken after Flight 261 crashed from a failed horizontal stabilizer jackscrew. The jackscrew controls the horizontal stabilizer and its threads were found stripped. NTSB investigators found that the jackscrew had not been properly lubricated, and that maintenance personnel were using an unauthorized and uncalibrated tool to measure the end-play of the machined threads. Alaska’s CASS system had not highlighted these problems to management. As a result, needed improvements to the CASS system were mentioned four times in the FAA’s “show cause” letter to the carrier.

Now, similar problems are emerging at American Airlines regarding CASS: it did not highlight the chronic problem with the engine starter assembly and did not catch the unauthorized use of a wrench or crowbar to wedge the starter button in place when the manual start procedure was applied.

The NTSB could have urged the FAA to look at the overall effectiveness of its CASS oversight, not only at American Airlines but at other carriers, too. CASS is supposed to enable carriers to manage effectiveness of maintenance themselves, without benefit of FAA inspector oversight. This clearly is not happening, and CASS has now been found to be seriously deficient at two major carriers this decade.

As NTSB Member Kitty Higgins asked at the 7 April hearing on this accident, “Where was the red flag to maintenance control to pull the plane and take a more serious look?’

NTSB professional staffer Ron Price answered, “The intermittent nature of the problem caused the MEL to go away.”

This answer explains why the ATSV was repeatedly given a “by” but does not adequately explain why maintenance control remained clueless as to the real problem.

As Member Robert Sumwalt recounted:

“One, maintenance was not following the company-prescribed procedure. Two, the pin had been bent by the unauthorized use of the prying tool during the manual start. Three, CASS didn’t identify the problem with the starter.

“These three bullet points lead me to believe that there were some systemic problems with American Airlines maintenance.”

As Acting Chairman Rosenker lamented, “We’ve seen it too many times, work arounds that lead to accidents.”

Despite the persistence of this ad hoc maintenance problem, the NTSB did not call on the FAA to look hard at its CASS program, which is required at all major carriers.

The other major problem in this accident was the crew’s failure to execute checklists, beginning with the engine fire checklist. NTSB staffer Dave Tew noted, “The failure to complete the engine fire checklist led to hydraulic failure, which led to the failure of the nose gear to deploy.”

Sumwalt sniffed, “I would not consider taking 3 minutes and 35 seconds to activate the [fire suppressant] bottles as immediate action.”

Sumwalt delivered a blistering sermon about the need for a sterile cockpit, one devoid of distracting chit chat in critical phases of flight such as take off and landing. “Less than two minutes after take off, the crew faced a critical emergency, but it took them a while to get spooled up” because of the lax and laid-back attitude in the cockpit, Sumwalt said.

Not addressed by the NTSB was the design of aircraft systems that led to multiple, cascading failures. For example, the airplane had two supposedly independent hydraulic systems, but the aircraft lost hydraulic pressure as both systems lost fluid. Hydraulic fluid being transferred from the right side to the failed left side all dribbled out, yet there was nil indication of this in the cockpit.

The apparent absence of FAA oversight was not addressed by the NTSB. It is clear, however, that when oversight is delegated to the operator, eventually “economics” replaces safety. This is evidenced by the simple fact that despite a dangerous yet mystifying problem, the airplane was kept in service. As Gabe Bruno, a former FAA official now in retirement, said of this case:

“It makes me damn mad. The FAA has abdicated any sort of safety oversight, and the deterioration of the system is stark evidence, from the carrier maintenance department, to training, to the flight crew’s attitude. The FAA calls this ‘System Safety.’ I call it a collective violation of the Public Trust.”

The interactions between the crew, the systems, the multiple mechanical and human failures, and so forth, are captured on the cockpit voice recorder (CVR), which ran throughout the emergency, from first fire alarm in the air to quiet moments later on the ground when the crew discussed the event. An abbreviated transcript of the recording is presented below, with NTSB investigative findings shown in bold. The account is gripping, as things just kept happening – such being the intrinsic nature of cascading failure. The fact that no one was injured does not detract from the important lessons to be gleaned from the event, some of which follow the transcript:

Time & Speaker Content NTSB Findings/ Recommendations & Other Comments
1:01:41Captain Steven Garber Okay, looks like we’re good to go … Let’s get clearance to push [back] then. NTSB: American Airlines’ maintenance personnel’s troubleshooting efforts for the engine no-start condition incorrectly focused on the air turbine starter valve (ATSV) and engine start system wiring because of the intermittent nature of the [normal starting system failure] condition, the history of ATSV electrical circuit problems, and the lack of a history of ATSV-air filter failures for which no troubleshooting guidance existed.
1:02:05Captain I’m ambivalent right now. I got six months to go.  
1:02:07First Officer Kevin May Do you really? … @ [non-pertinent word] # [expletive]. How many years you got?  
1:02:13Captain It’s not quite 18 for me by the time I get done, but I did active duty for 20 years.  
1:02:19First Officer Air Force or?  
1:02:21Captain Yeah, Air Force tankers.  
1:03:32Captain Brakes released, uh cleared to push tail west spot twelve. At pushback, sterile cockpit rule applies from ground movement to 10,000 ft.
1:04:29First Officer * * [unintelligible word] remember comin’ down during the F-100. Did you ever do that? Reference to Fokker airliner. Conversation violates sterile cockpit rule.
1:04:35Captain Not in the one hundred but I did it * * did on the inside in the eighty [MD-80] a couple of times before I got pushed off the seat. Conversation violates sterile cockpit rule. Conversation with first officer continues in this vein for a few more moments.NTSB: The casual atmosphere in the cockpit before takeoff affected and set a precedent for the pilots’ responses to the situations in flight and after landing, eroded the margins of safety provided by the standard operating procedures and checklists, and increased the risk to passengers and crew.
1:05:28Captain If you see anything prior V one, let me know. I’ll probably decide when we get within 20 knots of V one I think we’re flying, unless it’s catastrophic and ah. V1 is the speed where the aircraft can still come to a stop; beyond V1 it’s always best to get airborne.
1:15:56Captain Anyway, if uh unless we’re on fire we’ll go to Chicago. If we’re on fire we’ll land here. A prescient remark referring to the manual start of the left engine.
1:06:46First Officer Um I don’t know what the # they just did. “They” is the mechanics, who assisted in the manual engine start.
1:06:49Captain Well, they said they manually opened it for us. “It” refers to the start valve.NTSB: American Airlines’ maintenance personnel repeatedly used an unapproved maintenance procedure, which included using a prying device to push the air turbine starter valve manual override button, which resulted in bending the internal pin in the override button … the bent pin resulted in the uncommanded opening of the air turbine starter valve during high-power engine conditions at the beginning of the takeoff roll, causing the air turbine starter to catastrophically fail.
1:06:59Captain Let’s try not to screw anything up too much before I you know * .  
1:07:05First officer * * there’s 40%. Reference to engine RPM.
1:07:48Captain Flaps when you’re ready ah checklist and all that stuff when you’re ready, watch your feet. Casual attitude regarding checklist discipline.
1:07:59First Officer Yeah we have to get to Chicago * * * *. My wife’s coming in from Orange county.  
1:08:05Captain You takin’ her to Orlando?  
1:08:07First Officer No, she’s working tonight she works contract for ah flight attendant for McDonalds corporation at the base there so she was with us for 20 years 22 years and uh she’s coming in from Orange County. We’re gonna fly home in the morning to Grand Rapids * * # I got a hotel at the * Holiday Inn Select * * * * *. Conversation violates sterile cockpit rule.
1:08:50First officer How about flight instruments and bugs? Returns to before takeoff check list.
1:08:52Captain Okay, we’re set for uh standard runway ah 30 left at St. Louis *.  
1:08:58First Officer * * how about flap and slats?  
1:09:10Captain Set. Response should indicate the setting, further indicating casual checklist discipline.
1:09:59Captain Okay got two engines running just gotta make sure we have both of ‘em started [sound of chuckle].  
1:10:07First Officer I’m sure it’s been attempted before.  
1:11:48 [Sounds similar to aircraft accelerating on takeoff roll.]  
1:13:02First Officer Ah that # uh start valve light thing is * on. In its submission, Boeing noted: “No checklist action was taken by the flight crew ….“The first solid opportunity was when the start valve open indication was initially observed. The second item on the operator’s L or R START VALVE OPEN light abnormal checklist procedure is to bring the affected engine throttle to idle, thus greatly reducing the flow of pressurized, heated bleed air through the starter motor and into the engine nacelle. Prompt reduction of the bleed air flow could have prevented the failure of the starter and subsequent fire … 53 seconds elapsed between the moment the crew noted the start valve open indication and the fire warning activated, with the left engine power remaining at a high power setting (takeoff and then climb thrust).”
1:13:05Captain # I didn’t see that before. The air start valve was changed 6 times in 12 days, the last time 2 days before the accident. The left engine start switch was changed once. Left engine start valve operation was deferred under the Minimum Equipment List (MEL) 4 times, the last deferral on 27 September. The MEL provided for maintenance deferral of up to 10 days. Each time the MEL was reset, the 10 day period began counting. The airplane routed through one major repair facility during this period.
1:13:07First Officer Well * I didn’t either. American Airlines: “Currently, the start-valve-open light is an amber light on the cockpit’s overhead panel. This is not a conspicuous location, and it is next to other amber lights. Because the pilots need to get notice of an illuminated start-valve-open light so they can immediately throttle back on the engine to prevent overheating of the starter, which can cause a fire, American plans to connect the start-valve-open light to the master caution panel directly ahead of the pilots and in their line of sight.”NTSB: Coupling the air turbine starter valve (ATSV)-Open light with the Master Caution system might increase the pilots’ ability to detect the presence of an abnormal ATSV condition; however, unintended consequences, such as aborted takeoffs, may occur and more work needs to be done to determine whether the FAA should mandate the modification of the ATSV-Open light in the MD-80 fleet.
1:13:11Captain Does that mean the start valve is open? According to PTI Technologies, manufacturer of the start valve: “Examination of the Air Start Valve Filter from this accident and others received from American Airlines … indicate that the filter may be experiencing fatigue damage in the filter media material. This damage, if allowed to propagate over time, is evidenced as resulting in the eventual disintegration and separation of the filter material from its associated hardware.”So much for a so-called lifetime filter. All filters were replaced in American’s MD-80 fleet after the accident. Status of filters in other airlines is unknown.
1:13:13First Officer Ahm.  
1:13:14Captain Could very well mean that.  
1:13:55 [Sound similar to fire warning bell] Fire left engine. Boeing: “The crew did not initiate or complete the START VALVE OPEN ANNUNCIATION procedure, nor did they complete the engine fire checklist procedure …. The throttle was moved to idle approximately 1 minute after the fire warning actuated (2 minutes after the start valve open light); the crew initiated discussion of closing the fuel lever approximately 3 minutes after the fire warning, and initiated discussion of pulling the fire handle approximately 3 minutes and 35 seconds after the fire warning.”
1:13:58First Officer Fire light, oh my gosh. NTSB: The open air turbine starter valve and resulting failed air turbine starter allowed a hotter than typical airstream and/or incandescent particles to flow into the engine nacelle area and likely provided the ignition source for the in-flight fire.
1:14:02Captain All right we have to go back and land.  
1:14:10Captain Declare an emergency.  
1:14:15First Officer [On radio] Yeah, we’re gonna have to uh declare an emergency swing back around there and land at St. Louis.  
1:14:37First Officer You gonna fly or are you run * *.  
1:14:40Captain Run the checklist I’ll fly it. The captain did not say which of the two of them would operate the radios. If the captain had elected to operate the radios while flying, the first officer would have been freed of interruptions to concentrate on the checklist(s).
1:14:41First Officer You betcha. NTSB: The pilots failed to properly allocate tasks, including checklist execution and radio communication, which adversely affected their ability to conduct essential cockpit tasks, such as completing the appropriate checklists.
1:14:49First Officer Engine failure * * * fire one * * damage separation let’s see auto-throttles pilot flying off.  
1:14:59Captain Off. Flying now with manual throttles.
1:14:59First Officer Okay left throttle pilot flying idle * *.  
1:15:19St Louis departure controller * roger what’s the nature of the emergency? Do you need the uh equipment standing by it’s going to be short notice for ‘em. “Short notice” for the firefighters seems a misplaced concern here.
1:15:24First Officer Yeah, you’re gonna have to roll the trucks for us ah I got a left indication of a left engine fire.  
1:15:55Captain [responding to hi-lo chime from flight attendant] Hey this is @ uh I got a fire indication on the left engine we’re going back to land at St. Louis we’re probably gonna be on the ground in uh probably less than 10 minutes. After the accident, Boeing revised the Flight Crew Operations Manual (FCOM) engine fire procedures to include a caution note to leave the pneumatic crossfeed valves closed.
1:16:02Flight attend-ant No.1 All right.  
1:16:03Captain Okay I don’t think we’ll have to evacuate but uh if we do you know what the signal is it’ll be um easy victor easy victor three times.  
1:17:01 [Sound similar to fire warning bell.] Fire left engine.  
1:17:01First Officer Fire light.  
1:17:02Captain Okay yeah *.  
1:17:04Flight attend-ant no. 1 I’m gonna go tell these pilots up here what I just heard okay, I’m just gonna tell the pilots up here what I heard. NTSB: During the emergency situation, the flight attendants did not relay potentially pertinent information to the captain in accordance with company guidance and training.
1:17:07Flight attend-ant no. 2 What are you gonna say?  
1:17:08Flight attend-ant no. 1 Confirm that’s the left.  
1:17:10Flight attend-ant no. 2 She’s got the door open up there. Reference to locked cockpit door.
1:17:11Captain Well now it went out. Reference to engine fire warning.
1:17:12First Officer This thing is fallin’ apart.  
1:17:16 [Sound similar to fire warning bell.] Fire left engine.  
1:17:21First Officer Do you want me to kill this one?  
1:17:23Captain Yes.  
1:17:25First Officer Oh # I can’t even shut it off.  
1:17:32First Officer Ahhh fire handle.  
1:17:51First Officer All right it blew agent two.  
1:18:19 [Sound similar to the cockpit door being operated.]  
1:18:21First Officer * * * we’ve lost all # power * *.

Details, wiring harness and connector damage.

Details, wiring harness and connector damage.

American Airlines: “When the left engine was shut down, the airplane’s left generator and electrical bus was lost, causing the loss of the left half of the aircraft’s AC and DC electrical system. The right AC system is crosstied to the left AC system and would have normally provided AC power to the left system, but in this situation a fault-detection unit locked it out from the left AC system to keep it from being adversely affected by the left AC bus problems. The left AC bus in turn provides power to two transformer rectifier units that power the left DC electrical system. Since power was lost to the left AC bus, power was also lost to the left DC bus. The cockpit door-locking solenoid is powered b y the left DC bus, and the cockpit door came open when the solenoid lost power. This was a significant and loud distraction that the First Officer eventually corrected by closing and securing the door with the manual dead bolt. The Captain also started the auxiliary power unit (APU) but its generator did not go on-line, so it did not provide any electricity.”
1:18:27First Officer This # will not discharge.  
1:18:29First Officer [Sound similar to the cockpit door operating multiple times.] It’s not gonna shut. The flight crew later stated they were distracted by the cockpit door opening and closing during the flight. They also indicated they were distracted and confused by the loss of power to the left AC bus and the associated cockpit indications. Boeing: “These indications along with the crosstie lockout annunciation noted by the crew would typically lead a crew to perform the AC CROSSTIE LOCKOUT ANNUNCIATION procedure.”
1:18:34First Officer It’s that we’ve lost all power to them [sound similar to the cockpit door being operated] just hold it shut for me [sound similar to cockpit door being operated]. The latching mechanism to the door is powered by the left DC bus.
1:18:38Flight attend-ant no. 2 Why uhm why is the door keep opening up there?  
1:18:40First Officer Come on. I’m not gonna # with the door [sound similar to mechanical bang] #.  
1:18:48First Officer Can you op- close the door and I’ll latch it?  
1:18:48Flight attend-ant no. 1 No.  
1:18:49Flight attend-ant no. 2 I hear like pops and I don’t know if it’s the toilet or what it is.  
1:18:53First Officer [Sound similar to the cockpit door being operated] * # everything here. [Sound similar to the cockpit door being operated]All right * * # with that.  
1:19:05Captain I’m not going to # with this thing any more.  
1:21:03Captain Give me flaps 23. We got gear down, right?  
1:21:06First Officer Yep.  
1:21:07First Officer Your just not going to get anything ‘cause you’ve lost uh, everything here but.  
1:21:11Captain Okay.  
1:21:12First Officer I ain’t got time to # around figure out why. While a checklist would not answer the “why,” had the crew executed a relevant emergency checklist completely their situation would not have been as dire or confusing.
1:21:14Captain Yeah, I don’t either.  
1:21:15Captain I tried to start the APU but it’s not starting as far as I can tell. The APU started but did not go on-line electrically.
1:21:17First Officer Oh # * not showing ah shouldn’t we get this? The First Officer eventually reset the APU generator control relay and the pilots got electrical power back on the electrical bus. Normally, the power was picked up automatically and it did not have to be reset. Here is a major problem: automatic features didn’t work, increasing the crew’s workload.
1:21:21Captain Yeah.  
1:21:30First Officer I don’t get # gear either. We’re gonna have to manually drop these #.  
1:21:47St. Louis airport tower controller American fourteen hundred, uh, the mains appear to be down but I can’t I don’t there is no nose gear. I don’t believe there’s a nose gear.  
1:21:57First Officer All right, we’re gonna have to go around then.  
1:22:45First Officer [On intercom] Can you get @ ah other captain up here real quick? Reference to dead heading captain seated in cabin. The flight crew realizes that a third crewman in the cockpit will alleviate workload. The dead heading captain will occupy the jump seat.
1:22:47Flight attend-ant no. 3 Yes – he’s comin’.  
1:23:11Jump seat captain # okay, I can’t latch these doors. A reference to the failed electrical lock on the cockpit door.
1:23:43First Officer Yeah it’s all dead * * * # everything in this side.  
1:23:47Jump seat captain All right.  
1:23:48Captain So we’re gonna lose the other engine if we’re not careful.  
1:24:04Captain There’s no way to get the nose gear down right?  
1:24:05First Officer I don’t think so.  
1:24:07Captain We’re just have to go back and land ‘cause I can’t maintain airspeed.  
1:24:39Jump seat captain We’re gonna land with the nose gear up? NTSB: The pilots’ interruption of the emergency Engine Fire/Damage/Separation checklist at a critical point prolonged the fire and led to additional problems, including the loss of hydraulic pressure, which caused the nose landing gear to fail to extend.
1:24:47First Officer Yeah.  
1:24:48Jump seat captain And the mains are down?  
1:24:49First Officer Mains are down they’re stayin’.  
1:24:51Captain And I can’t hardly turn us. Without hydraulic power, the aircraft is very sluggish at the controls.
1:25:24Jump seat captain Are you gonna wanna evacuate or no?  
1:25:26Captain * not unless we have to.  
1:25:54Captain I can’t get this sucker to climb.  
1:26:00Jump seat captain You’ve lost the all ah hydraulic pressure on the right side. Boeing: “In the event of a hydraulic loss in one system, an automatic PTU [power transfer unit] shutoff system will close the motor-operated shutoff valve when the hydraulic reservoir diaphragm assembly decreases below a preset value … If the PTU is not shutoff by the flight crew or by the automatic system, and there is hydraulic fluid loss in one system, the hydraulic fluid flow into the PTU can result in low hydraulic system pressure in the operating hydraulic system. The likely result is the loss of power in both hydraulic systems.”So much for independent redundancy.
1:26:03First Officer How the # did that happen?  
1:26:05Captain I don’t know.  
1:27:25First Officer No we got, we’ve got no # hydraulic pressure on the right side for some odd reason. American Airlines: “At some undetermined point, the airplane’s hydraulic system began to fail, and the hydraulic quantity gauges were apparently giving inaccurate readings. The loss of hydraulic pressure also precluded normal operation of the rudder.”
1:27:32First Officer That engine’s runnin’. The right engine is operating, but there is no right side hydraulic pressure, which mystifies the crew.
1:27:33Captain Totally # up, we’ve got no left engine, we’ve got no hydraulic pressure on the right side, we don’t have any hydraulics on the left side.

The fire-damaged left hydraulic pump. The case was fractured, and when investigators pumped 20 psi hydraulic fluid into the pump, the fluid escaped through the fractures.

The fire-damaged left hydraulic pump. The case was fractured, and when investigators pumped 20 psi hydraulic fluid into the pump, the fluid escaped through the fractures.

Boeing: “Apparently, during the accident flight, depletion of the fluid in the left hydraulic system and the continued operation of the PTU resulted in loss of right system hydraulic power to the flaps, rudder, landing gear extension system, nose wheel steering, and other systems … the PTU was absorbing the right system’s power such that insufficient power remained to actuate other aircraft systems.”A powered right hydraulic system would have allowed the crew to land on the first attempt, as well as power the flaps to the selected positions and power the rudder to assist with engine-out controllability.
1:28:37Jump seat captain You want me to say anything to the passengers?  
1:28:40Captain Yeah, go ahead and tell ‘em what you can.  
1:28:54Jump seat captain [On public address] Well, ladies and gentlemen, from the uh flight deck obviously we have a problem with the aircraft ah we are returning to the uh airport for landing ah please pay attention to the flight attendants completely I you probably will have ah * * * * aircraft as we roll out on the runway ah at this point do not be alarmed by that * * but flight attendants * * * information right now please everyone be in your seats with your seat belts fastened. Four asterisks: probably a reference to fire trucks.
1:30:17Jump seat captain [On intercom to flight attendants] @ we are not going to do a ground evac yet * for now but be ready.  
1:30:59First Officer Got a lot of speed *.  
1:31:03Captain Okay, flaps 28.  
1:31:17Unclear who’s speaking Do we have a split flap? American Airlines: “The loss of hydraulic pressure kept the flaps from responding to the cockpit settings, and the flaps never moved beyond 8 degrees before landing. The pilots did not know what the flaps were actually doing because the electrical problems made the flap gauges difficult to interpret.”
1:31:19First Officer Uh no they’re just not working.  
1:31:24Captain Yeah they are.  
1:31:23First Officer Lost all # power to it I guess.  
1:31:33First Officer Uh well we’re landing checklist complete so. This mechanical checklist was the only one completed, and without interruption.
1:31:37Captain Landing.  
1:32:12 [Sound consistent with aircraft touch down on runway.] Total time of flight from rotation on takeoff: about 20 minutes.
1:32:29First Officer Pull her outta reverse, stand on the brakes.  
1:32:46Tower American fourteen hundred did you want to stop on the runway?  
1:32:49 [Sound of passengers clapping.]  
1:32:49First Officer [On radio] Yeah we’re gonna stop here.  
1:33:13Jump seat captain [On public address] Ah, ladies and gentlemen, you will ah see fire equipment ah moving towards the aircraft and checking the aircraft out that is ah precautionary we did have a left engine fire indication they are checking that out so ah right now we have no indications that it as an actual fire we did ah shut that engine down ah please stay seated.
Cowling removed, showing blackening and extent of damage.

Cowling removed, showing blackening and extent of damage.

1:33:19Tower American fourteen hundred when you get just a moment change to ground twenty-one nine and he’ll talk to you. The first of numerous failed attempts to put the flight crew in direct contact with the fire trucks.
1:33:28First Officer And ground American fourteen hundred we’re up on twenty one nine.  
1:33:49Captain American fourteen hundred uh to ah rescue crew.  
1:33:53Truck 42 Yeah go ahead.  
1:33:56Jump seat captain You don’t have to go to recurrent for two years. A joke; after this experience the flight crew will not need to go to recurrent training for a while.
1:33:58 [Sound of laughter.]  
1:34:03Truck 42 ARFF to ground left engine still a little bit of fire in there. ARFF: airport rescue and fire fighting.
1:34:08First Officer You gotta be # me.  
1:34:12Captain You fire the other bottle? Each engine is equipped with two bottles of fire suppressing agent.
1:34:19First Officer Think they’re both gone I shot ‘em both.  
1:34:50Captain [On radio] All right are they gonna spray it?  
1:34:53St. Louis Ground Controller They’re working on it now I believe.  
1:35:11Captain Hey ground when uh American fourteen hundred when they get this thing all ah secured here we’re gonna have to be towed back I don’t have any nose wheel steering or anything.  
1:35:23Ground American fourteen hundred are you going to be evacuating the aircraft?  
1:35:25First Officer Uhh no there’s nowhere for anybody to go the guys got a handle on it right now they’re gonna shoot it for us.  
1:35:37Jump seat captain Well they got busses standing by over there.  
1:35:39First Officer Sweet.  
1:35:44Jump seat captain That can’t be for us that’d be too well coordinated.  
1:36:03Captain We had a left start valve open light. Boeing issued a warning in 1979 telling MD-80 operators that an airline had experienced an open valve indication. Inspection revealed the override valve pin was bent. Boeing’s letter warned of pin damage during actuation when a force greater than hand pressure was applied. On the accident airplane, the valve pin was found bent from mechanical force being used in an ad hoc maintenance procedure. Turns out the pin gets hot and mechanics found it convenient to use some sort of metal lever against the pin when manually starting the engine.
1:36:05Jump seat captain Open?  
1:36:06Captain After we got airborne.  
1:36:15Captain We had all kinds of # goin’ on there.  
1:36:17Captain * * * electricity went away uh you know * I started the APU but it didn’t come on line that AC cross-tie lockout goin’ and you know like # I’m like baffled.  
1:36:26Jump seat captain @ I’d hate to have been in the weather.  
1:36:42Captain Did you say something to the people?  
1:36:43Jump seat captain I told everybody to stay seated ‘cause there was fire trucks will be out.  
1:36:46First Officer Extra pay in this for you.  
1:36:54Jump seat captain You were like your hands were full.  
1:36:56First Officer # yeah I * * * no * [sound of laughter]  
1:37:01First Officer Did I tell you this # always happens to me?  
1:37:04Captain No. Remind me to put you on my do not fly list.  
1:37:18Captain [On radio] Hey ground American fourteen hundred.  
1:37:16Ground American fourteen hundred go ahead.  
1:37:18Captain Yes sir I was just wondering does anybody on the rescue crew ah are they monitoring this frequency ‘cause they’re not talking to me? According to the Allied Pilots Association (APA), the union representing American Airlines pilots: “The ARFF personnel inserted their headset plug into the cabin interphone jack instead of the cockpit jack, while attempting to establish ground-to-ground communication.”APA recommended: “That the FAA require all U.S. commercial aircraft to have a placard installed clearly indicating the appropriate communications jack for ARFF use.”
1:37:24Ground They should be.  
1:38:39Captain [On radio to Ground] Okay we uh ground uh American fourteen hundred uh open further review here we think probably we’re smarter to just wait and let ‘em tow us so we’re not sure we have enough hydraulic pressure to hold the gear up.  
1:40:27First Officer We got some A-C goin’ on. That’s cool. A-C: air conditioning.Boeing: “The flight crew decided to operate the left air conditioning pack to provide additional air to the cockpit and cabin, and opened the left pneumatic crossfeed lever. Opening the left crossfeed valve reset the left fire handle, which re-opened the left fuel and hydraulic systems fire shutoff valves, resulting in a fuel discharge from the left engine area. Ground firefighters advised the cockpit crew of the fuel discharge, and the fire handle was pulled once again to shut off the fuel.”
1:40:40Captain [On public address] Okay folks this is captain @ speaking um we have things under control here for the most part ah they are gonna bring a tug out to the ah runway here to tow us off the runway ah hydraulic pressure is gone and we don’t really have any steering capability right now the safest thing to do is tow the airplane in um we’re talkin’ to operations to see where they’re gonna put us but ah the rescue people have secured the airplane and everybody is good on the outside so ah just be a couple of minutes here I think before we ah standby. NTSB: Operational procedures requiring that an airplane be configured for an evacuation when it is stopped away from the gate after a significant event would help expedite an emergency evacuation if one became necessary.
1:40:40First Officer # * * *. Well that’s comin’ up.  
1:41:00Jump seat captain Hey.  
1:41:01First Officer * * * *.  
1:41:02Jump seat captain [Sound of laughter] * * * *.  
1:41:08First Officer * like ah * * then I couldn’t even shut this * * * and shut fuel *.  
1:41:17First Officer Pull the fire handle couldn’t rotate it. In subsequent interview with NTSB investigators, the first officer said the fire handle in the airplane was much harder to pull than in the simulator, where it is exercised all the time.
1:41:21Jump seat captain Wow.  
1:41:22First Officer * I don’t know what * * really * this is it * * * release and then couldn’t even get it to go any further than that * * push it on down. Describes difficulty in manipulating fire handle.
1:41:22Captain * come on?  
1:43:28Captain [On public address] Folks this is captain @ the ah rescue crew just said they wanted to come on board and check things out inside ah they’re gonna be comin’ up on the front door here of the left side.  
1:44:24Flight attend-ant no. 2 [On cockpit-cabin interphone] Can they use cell phones they wanna know.  
1:44:29Jump seat captain Yeah.  
1:44:30Jump seat captain [In cockpit] Yeah your not gonna fear for the navigation equipment now eh. Tests have revealed that cell phone use can interfere with aircraft systems.
1:44:33First Officer [Sound of laughter] What we have left.  
1:45:12Captain So when this thing * * * when you cut this and the left engine shut down so we didn’t even get follow any checklists like we’re supposed to you know. His decision to have the first officer handle the radio and the checklists set the stage for checklist interruption and failure to complete any of the required check lists. However, the captain said he had difficulty controlling the airplane (unusual stick and rudder force required due to thrust asymmetry, manual rudder, elevator column force needed to counter depowered horizontal stabilizer pitch trim).The following are applicable checklists:• L or R START VALVE OPEN light – this checklist was not performed.• Engine Fire/Damage/Separation – this checklist was performed in part but was interrupted at one point.• One Engine Landing – this checklist not performed.• Emergency Landing – not performed.• L or RT HYD PRESS LOW light – this checklist not performed.

• L or R Hydraulic Quantity Low or Decreasing – not performed.

• Before Landing – performed.

• After Landing – not performed.

• Parking – unknown if performed.

• Ground Evacuation – not performed.

1:45:20Captain I’m just like keep this thing flyin’.  
1:45:24First Officer Yeah * like bring it around and land it you know get what # you can get done and then course we’d a been down quicker if it was.  
1:45:31First Officer You got ‘er do an overweight landing.  
1:45:33Jump seat captain [Sound of laughter]  
1:45:37First Officer You can punch me any time * * just don’t hit my shoulder.  
1:45:45Jump seat captain Oww.  
1:45:52First Officer I suppose now we’re gonna have to debrief all this #.  
1:47:20Captain [To ARFF personnel] And you can see it from the rear you cannot see it from the front? Captain refers to fire damage on left engine.
1:47:23ARFF Well I mean it’s burnt all the way through underneath that engine.  
1:48:04Captain So we probably just cheated death by that much I think.  
1:48:20Jump seat captain The electric the hydraulics * * melted lines and wires shorted # out. There’s no such thing as a simple fire is there?  
1:48:29 [Sound of laughter.]  
1:48:29Captain But I was getting’ a little worried because it seemed like I was having to use more and more aileron to keep the wing up and ah I wasn’t climbin’ and ‘course I had the gear down so you know I‘m not gonna climb.  
1:48:59First Officer Well now we’re down to APU power. [Sound of laughter]  
1:49:02Captain Okay now we’re a glider.  
1:52:12Captain Yeah * as soon as that happened I’m thinkin’ well you know if you were doin’ on an engine start and it didn’t ah close what do ya do you shut the engine down. We shoulda just immediately headed back to the field when that happened * *. Crew discusses their actions and whether they were timely.“When that happened” refers to the left start valve open light illuminating.
1:52:22First Officer Well yeah in retrospect yeah but I mean *.  
1:52:55Captain But I mean we were headed back to the field almost right away.  
1:52:27First Officer But it was.  
1:52:28Captain I mean yeah it was like seconds.  
1:52:30First Officer And you weren’t even at what four thousand feet?  
1:52:33Captain I never got we never got above four thousand.  
1:52:34First Officer Basically what it says is go to in-flight shutdown, * * * again so.  
1:53:06First Officer Well good thing he was on board * * * too # much for # two people to be # with * you got just a simple thing * you got this now we got this.  
1:53:20Captain Well what do they say you know in the simulator they’re not allowed to give us compound emergencies right? The NTSB factual reports illustrate the lack of any formal flight crew training that addresses multiple system failures and complex emergencies.For instance, during a simulated engine fire event, the crew always had the autopilot available.A scenario very much like this accident is now included in American’s simulator syllabus.NTSB: Improved pilot training methods for responding to multiple systems failures, competing task demands, and increased workload would help pilots develop skills and decision-making abilities during both single and multiple abnormal and emergency situations.
1:53:30First Officer I mean you lost electrical, and it never cross-tied.  
1:57:41 [Warning bell and electronic voice] Fire left engine. Note: passengers are still aboard. The plane has been sitting on the runway for 24 minutes.
1:57:44First Officer Oh, you gotta be # me.  
1:57:44Captain Oh.  
1:57:46First Officer I just moved that thing and it just.  
1:57:51First Officer That’s ‘cause it went back in when I pulled it yeah *. I was just lettin’ the air back in. * * * * * pull it back out. # # it was hot. The earlier attempt to get air conditioning into the cabin obviously backfired.
1:58:06 [Sound similar to voice originating from outside the cockpit] Dumping gas.  
1:58:07Ground maintenance staffer Cockpit, ground, pull the left engine isolation, pull the left engine shutoff valve. You’re dumping fuel.  
1:58:09Captain Is it still dumpin?  
1:58:12First Officer How the # * this # all off? NTSB: The first officer did not have a clear understanding of the relationship between the pneumatic crossfeed handle and the engine fire handle … which resulted in the first officer inadvertently reintroducing fuel to the left engine, creating unnecessary risk of fire.
1:59:06Ground maintenance Do you have the left engine fire pull pulled?  
1:59:08Captain Yeah uh yeah we did uh pushed it back in for a moment, but it’s out now.  
1:59:36Ground maintenance Okay do you have uh are the right hyd- why do you have uh you have no right hydraulic either. The mechanic doesn’t understand why a fire on the left engine has affected hydraulics on the right side, since the systems are supposed to be independent of one another,
1:59:37First Officer But the loop’s testing right? A reference to the right side hydraulic system.
1:59:53Captain You’re plugged into the cabin interphone. Can you plug into the other the other interphone slot? Continuing communications problems between the air crew and ground staff.
1:59:56Ground Okay.  
2:00:16Captain Can you hear me now? How do you hear? You still don’t hear me?  
2:03:56Captain [To Ground] Yes sir uuuh some of the crash folks are saying they want to deplane the people here but we don’t understand why they want to do that we’re hooked up and ready to be towed ah in just a couple minutes and uh that’s all going to take that much longer.  
2:04:43Captain For a while there we didn’t have much of anything. I don’t know what was going on. I was just trying to keep the blue side up. “Blue side up” is a reference to the artificial horizon and the captain’s desire to keep the sky on top and the ground on the bottom of the indicator.
2:05:04Ground Car 19 go ahead.  
2:05:05Emergency response Car 19 I spoke directly to the chief they wanna deplane the passengers there’s still heat and uh smoke coming out of the left engine they want to deplane the passengers outta here.  
2:05:28 [Sound of voice originating outside the cockpit.]  
2:05:31Captain Well we pushed the handle in, we pushed the fire handle in for a moment.  
2:06:06First Officer I think it’s asinine to send people out on the busses but.  
2:06:12Captain When you ah pushed on the fire handle in that started dumping fuel * *.  
2:06:21First Officer That’s my fault there.  
2:07:12Flight attend-ant no. 3 So I need to disarm this door and we’ll use the front entry with stairs and do we need to talk them into keeping all their crap on the plane ‘cause their gonna try to carry all their crap. “Crap” refers to carry on baggage.
2:08:28Captain Can we just let ‘em take all their stuff off they probably should just take everything with them.  
2:08:35First Officer Got a screw driver? To open cockpit door, whose lock is not functioning because of the electrical problem.
2:08:37Captain Naw I’m not allowed to carry on, but I do have something that might work just as well. Here, try this.  
2:08:38 [Sound of laughter.]  
2:0843Flight attend-ant no. 3 I have scissors.  
2:08:46First Officer There we go those # are hot.  
2:08:51Not certain who is speaking Whoo.  
2:08:52First Officer That thing burn your hand too?  
2:08:53Captain Yeah. I didn’t burn it that bad. I used a rag.  
2:09:05Captain Are we still on the clock then? A reference to getting paid.
2:09:06First Officer * * * * [Sound of laughter]  
2:09:07Flight attend-ant no. 3 Would you be sure on that. I’m not sure about all their stuff. I think they’ll fall down the stairs and break their necks carrying their bags so I’m not sure what the procedure is.  
2:10:05Captain [On public address] This is the captain speaking uuhm the fire department has now decided they saw some residual fuel draining out of the left engine which was the engine that we had a problem with uh in the interest I guess of being very cautious they want to deplane all of you folks uh out here there are some busses standing by uhm they’ve told me that they would request that you leave your carry-on luggage on the airplane you’ll be able to get it once we get back to the terminal area but they want to take, in the interests of safety, they want you folks to get off the airplane and then they’re gonna tow us back into a gate, so I’d appreciate your cooperation ah just take the minimum amount of things you need to take with you but if you could leave your carry-ons on the airplane ah that’s what the fire department instructions were thank you. Passengers debark with many expressions of thanks to the captain, who tells one passenger “There was never a problem.”
2:12:35Captain [To flight attendant no. 3] We were just overwhelmed what stuff happened.  
2:12:37Flight attend-ant no. 3 I said everything went wrong at once isn’t that what they always say on TV, the cascading of events. Probably always say that when they talk about *.  
2:12:45Captain * * stuff happening and you know when * it all goes back to changing that start valve.  
2:13:06Captain First thing we had was we * we got the gear up and we got up to about I don’t know twenty three twenty five hundred feet or so and was just turnin’ out of traffic and we got a indication that the left start valve was open which you can’t have * you can’t in flight it’s not a good thing you know * I goin’ oh shh.  
2:13:27Flight attend-ant no. 3 I heard all that stuff goin’ on.  
2:13:28Captain Time to think about yeah before we had time to even figure out what are w- do with that next thing we got was * fire light and then we’re losing stuff.  
2:13:40Flight attend-and no. 3 And the gear wouldn’t go down?  
2:13:41Captain Gear wouldn’t well the nose gear wouldn’t go down that’s why I went around the first * and then I’m out there and I’m goin’ I’m havin’ a # of a time holdin altitude. American Airlines: “The primary trim for the stabilizer was … not functioning because of the loss of the left generator bus. This was quite distracting because constant pressure was required on the control column to hold altitude … when electrical power was lost.”
2:13:52Flight attend-ant no. 3 Oh my.  
2:14:22Flight attend-ant no. 3 # door kept opening I couldn’t get the door shut. Cockpit door.
2:14:23Captain We lost *, we’re losing our instruments up here, and ah so I said get [dead heading captain] up here we need a third guy. So much for the adequacy of the two-pilot cockpit.
2:14:32Flight attend-ant no. 3 Yeah that’s good.  
2:14:57Captain Thirty five years of flyin’ that’s the first time I’ve ever had anything like that happen.  
2:15:07Flight attendant no. 3 The only thing I’ve had are a couple of aborted landed because there’s a plane or somethin’ on the runway and that’s it I’ve never had anything I was really kinda hopin’ once we’re on the ground I really wanted to do that evacuation ‘cause I’ve never done * * * training. In training, flight attendants do not practice an emergency evacuation with volunteers acting as passengers.
2:15:19Captain Oh yeah well I just I was you know unless we were burnin’ up I didn’t wanna dump all the people out there.  
2:15:25Flight attendant no. 3 Oh year ‘cause then they’ll all break their legs goin’ down the slide.  
2:18:10Dead heading first officer from previous flight Hell of a job, guys. Unbelievable, no flaps no spoilers.  
2:18:13First Officer Did we have any flaps? I mean I don’t know.  
2:18:17Dead heading F.O. You didn’t have anything for the landing.  
2:18:18First Officer Didn’t we?  
2:18:19Captain Is that right? We didn’t have any flaps?  
2:18:22Dead heading F.O. No flaps, and you had no spoilers.  
2:18:23Captain We really didn’t know what we had.  
2:18:26First Officer It’s showin’ that they’re down to 28. Flaps were set for 28 degrees.
2:18:30Dead heading F.O. They were nothin’ when we landed.  
2:18:35First Officer So like I said everything started going start valve light came on and then the fire light came on and after that everything just went * * *. Everything froze. I mean and then had A-C crosstie and then you wouldn’t believe all the # that went wild and I mean it’s just.

AC generator housing breach.

AC generator housing breach.

The filter manufacturer, PTI, issued an updated release May 2000, which recommended:1. Disassembly of the filter element from the filter case.2. Discarding of the metal seal.3. Cleaning and drying of the filter element and case.4. Visual examination of all components for signs of damage or inadequate cleaning.5. Repair or replacement of parts failing the visual check.6. Reassembling components with a new seal and lockwire.

PTI maintains: “The evidence presented from the accident leads PTI … to conclude that American Airlines’ maintenance practices were inconsistent with the practices above … the basis of this conclusion is twofold:

1. The extent of damage incurred by the Air Start Valve Filter … was likely the result of the filter remaining in a damaged state for a significant period of time …

2. The recommendation for inspection, post cleaning, for the presence of damage would have … resulted in a repair or replace disposition…”

NTSB: Boeing and PTI inspection criteria for the air turbine starter valve (ATSV)-air filter are inadequate to detect early-stage fatigue fractures of the outer mesh of the filter element and, because of the ATSV-air filter design, the inner mesh of the filter element cannot be inspected for evidence of fatigue.

2:21:28Captain They slipped a new- they put a new start valve in and-  
2:21:30Ground maintenance No, they didn’t change the start valve. According to American Airlines: “[On] the filter removed after the accident … the internal wire mesh ‘cloth’ was found to be almost completely deteriorated. This would have been visible only if the filter had been disassembled and inspected internally. Moreover, the mesh had deteriorated to the point that its nickel-sized cap was liberated and allowed to move around inside the filter and so to intermittently restrict or block the airflow through the filter. Neither Boeing nor PTI provided American any maintenance-manual procedures for troubleshooting and detecting restriction or any blockage of the control-air supply line, and American had not been informed of any previous history of restriction or blockage of the control-air line.”However, Boeing All Operator letter of 1997 did warn of bent override pins and, according to the APA, “The air carrier did not deactivate the valve in accordance with the Boeing procedure.”
2:21:32Captain Hah?  
2:21:33Maintenance They just they didn’t change the start valve they just opened it up manually. American Airlines: “[Because] of the concern about the deterioration of the air filters over time, and because American has requested but not received from Boeing or the filter manufacturer, PTI, any data about the filter’s failure mode or its lifespan, American has installed new filters on all of its MD80-series aircraft. American has also introduced a requirement for a close visual inspection for degradation of the wire-mesh screens inside the filters when the filters are disassembled for cleaning during ‘C’ checks.”NTSB: American Airlines’ maintenance personnel were using maintenance procedures that were not in accordance with written manuals and guidelines, and its Continuing Analysis & Surveillance System (CASS) did not adequately detect and correct these performance deficiencies before they contributed to an accident.
2:21:34Captain Oh they didn’t. Well. He said they were gonna change it. NTSB: American Airlines’ maintenance personnel did not clean the accident air turbine starter valve air filter in accordance with its C check cleaning procedures and, therefore, missed an opportunity to identify and replace the damaged filter.
2:21:38Maintenance Well they couldn’t open it up … there’s a button on there that you can use to open it up ahm manually but the button wouldn’t open the valve. The button wouldn’t open the valve because the shaft to which it was attached was bent from prior attempts to force it with a tool.According to American Airlines: “It is painful to push the button for a full 40 seconds with a thumb or finger because the pushbutton has a very small diameter and also because the valve body becomes painfully hot when starter pneumatic air flows through it. Although it was not authorized by American … mechanics sometimes used a lever to push the button.”
2:21:51Captain Thought you hadda put a wrench on it  
2:21:53Maintenance Well that’s what they did they put a wrench on it  
2:23:01Captain Yeah we couldn’t figure out what was goin’ because about that time ah we had cut off the fuel to the left engine you know to shut it down and my left generator wound down and next thing I knew my instruments were goin’ crazy we got a crosstie lockout up here I reached up and moved the APU master switch to start I’m tryin’ to get the APU up and it came up I guess but I could never really tell that I ever got electricity back so then when we got on the runway ahm. American Airlines: “The cockpit instruments began to act ‘strange’ and to fail. Some instrument warning lights went on, and others went off. The Captain’s and the First Officer’s digital flight panels went blank. The Captain’s primary flight display and navigation display both went off and on before they stabilized and stayed on, but they continued to give erratic displays. Other instrument readings froze in position (some at zero), were inconsistent with other instruments, or were also erratic. An estimated one-third of the overhead annunciator warning lights were illuminated.”
2:23:07First Officer You gotta be # me.  
2:23:18Maintenance Well there’s a lot of wiring that burned up.  
2:23:39Captain Did I ever get the reverser out? Just wonder if I got the right reverser out because it did start-  
2:23:44Maintenance (The) accumulator would’ve shut the reverser down.  
2:23:46Captain Yeah, so I got the right reverser open then I started goin’ to the right and I almost couldn’t stop it. * pushin’ with everything I had on the left rudder and uh once we got it down to slow speed I could even work the tiller. “Tiller” refers to nose wheel steering.
2:24:20Deadhead F.O. You guys had nothin’ you had the slat you had nothin’ else. In other words, no flaps for landing.
2:24:28Captain No #.  
2:24:30Captain Good thing I didn’t go any slower, huh? A slower speed, without flaps deployed, would have stalled the wing.
2:24:31First Officer Well yeah in retrospect yeah.  
2:25:33First Officer You guys gonna take it out of service or?  
2:25:35Maintenance Oh yeah it’s out of service yeah.  
2:25:36 [Sound of laughter.]  
2:28:08FAA official Did you pull the breakers for the ah voice recorder and ah?  
2:28:11First Officer No.  
2:28:12Captain No.  
2:28:12FAA official Go ahead pull ‘em.  
2:28:13First Officer Alrighty we’ll get ‘em wherever the # they’re at.  
2:28:16FAA official You’d wanna preserve that you’re a hero.  
END OF RECORDING

 

Some object lessons to take away from the CVR transcript:

  • The CVR is rarely going to be a pilot’s friend. The less said the better.
  • The danger from bleed air leaks should never be underestimated. High pressure (HP) stage bleed air may be on the order of 1,000º F or higher. That air is HOT and most certainly will set off fire warning systems, cook electrics and disrupt hydraulics. Accidents where people died because of an uncontrollable bleed air leak have occurred.
  • With the demise of the flight engineer (Second Officer), once the two-pilot airliner is delivered to the operator, it is incumbent on the airline to maintain the automatic safety features (AC Cross Tie Relay, APU Generator Relay, etc.), and passengers depend on pilots to reject any aircraft where these automated safety features are routinely unreliable.
  • After reviewing the failure interactions in this accident (loss of the Left AC Bus, loss of BOTH hydraulic systems, after suffering a mere failure of the left engine), it is fair to ask if the original certification precepts have been abandoned. Consider some of the original engineered safety features:

The AC Cross Tie Relay was designed to guarantee power to the buses once the failed engine’s generator dropped off line.

The automated APU Generator Relay shouldn’t need any attention from pilots in an MD-80 cockpit; the automatic features should have provided power to the Left AC Bus once the captain had stroked the APU Start Switch from Off to START. A 2-pilot cockpit was designed for this one-stroke automation – without inducing distractions to the First Officer, who was instead forced to take on the added role of Flight Engineer (forced to investigate failed automatic features, then reset the APU Generator Relay).

Had the2-pilot cockpit automated safety features operated as designed, this mishap would have been much simpler, and the pilots would have had normal electrical and hydraulic systems, and they would have completed their immediate return for landing, without the go-around (due to gear and flap anomalies) with an active FIRE indication.

Consider some remarks from the Boeing submission:

In the event of a power loss on the load buses of either side, a crosstie relay is provided so that the unpowered buses can be connected to the power source energizing the buses of the opposite side …”

“…function of the AC crosstie relay (ACTR) is to automatically connect the left and right AC generator buses together under certain conditions, thereby permitting both buses to be energized by a single generator …”

“If power is lost on one bus, the ACTR is designed to automatically close when the associated dead bus sensing circuit senses a loss of power on the bus …”

In summary, when automation gives up the ghost, the human element becomes the paramount factor in survival. Their loquacity and interim confusion and indecision notwithstanding, the pilots deserve credit for having adequately filled the emergent gaps when automation failed and supposed built-in redundancy was lost.


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