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‘Most Wanted’ List Updated to Account for Reality

Tue, Nov 11, 2008 — David Evans

Articles, Featured

Changes have been made to the “Most Wanted” list of recommendations to reflect progress, or lack thereof, in improving the state of aviation safety. At its annual meeting 28 October to discuss the list of needed improvements, the National Transportation Safety Board (NTSB) added an entire class of operations – emergency medical services (EMS) flights – while fuel tank safety was removed in light of Federal Aviation Administration (FAA) actions.

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The “Most Wanted” list has been published annually since 1990 to raise public awareness of the need and to galvanize needed regulatory actions, most notably by the Federal Aviation Administration (FAA). This year, for the first time, an entire class of flying, helicopter ambulances, was added to the list.

“We recommended improvements in 2006,” for EMS operations, almost three years ago, and the FAA has either not acted, or has issued only advisory guidance, not required actions, said NTSB Member Deborah Hersman.

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Member Robert Sumwalt noted that in 2006 the NTSB recommended EMS helicopters be equipped with terrain awareness warning systems (TAWS). That recommendation was issued as part of an NTSB Special Investigation Report (No. PB2006-917001) into EMS operations. Of 55 accidents studied in the report, as many as 17 could have been prevented if the helicopters had been equipped with TAWS. As NTSB staffer Jeff Guzzetti pointed out, the FAA has required TAWS on turbine-powered airliners with six or more passenger seats. The fitment of TAWS has not only reduced crashes from controlled flight into terrain (CFIT) in North America, the warning technology has also resulted in fewer CFIT crashes worldwide. As the UK’s Civil Aviation Authority has recounted in its global fatal accident review, “Available evidence shows that there has yet to be a genuine fatal ‘CFIT’ accident involving a TWS equipped aircraft.” (See Aviation Safety & Security Digest, ‘Study Shows Aircrew Errors Cause Most Fatal Accidents,’ home page).

Guzzetti recounted that there have been nine EMS helicopter crashes in the past 11 months, seven at night and five in reduced visibility. TAWS would have helped to avoid some of these crashes and the 35 fatalities that resulted.

Hersman spoke for both her own and fellow board members’ frustration. “The FAA hasn’t even entered into rulemaking” on TAWS for EMS flights. “People are dying and we need a sense of urgency that I don’t see. The whole purpose of this segment of the aviation industry is to save lives, and what we’re seeing is a disproportionate accident rate that belies that.”

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As Sumwalt remarked, “It will be five years between our TAWS recommendation [for EMS flights] to the time the FAA’s rulemaking is completed.”

His 5-year estimate is based on the optimistic assumption that the FAA issues a notice of proposed rulemaking (NPRM) sometime in the first half of 2009.

The NTSB members were of the view that the FAA is not working quickly enough on its proposals, and therefore voted unanimously to elevate the 2006 EMS recommendations to the annual list of top safety priorities.

An FAA official said the agency has “worked extensively and aggressively with EMS helicopter operators to improve safety and to adopt better safety procedures and technology.”

His riposte does not account for the agency’s failure to move beyond guidance material to required standards.

EMS helicopter operators are not yet required to have TAWS. Following the 28 September crash in Maryland of a state police EMS helicopter, state senators John Astle and Edward Pipkin wrote the Maryland Institute of Emergency Medical Services System (MIEMSS) and the Maryland State Police. Among the 38 questions in their 17 October letter was this: “Why didn’t Trooper 2 [the radio call sign of the accident helicopter] have the federally recommended equipment (Terrain Awareness System – TAWS) to notify the pilot that he was flying too close to the ground.” The short answer is that the equipment is only recommended; it has not been required by the FAA as a precondition for approving the flying entity’s operations specification (OpsSpec). (See Aviation Safety & Security Digest, ‘Safety of Helicopter Ambulances Questioned by Maryland State Senators,’ home page.)

Twelve years later and after years of FAA half-measures, fuel tank safety was removed from the NTSB’s ‘Most Wanted’ list.

Twelve years later and after years of FAA half-measures, fuel tank safety was removed from the NTSB’s ‘Most Wanted’ list.

 

 

 

 

 

 

 

 

While the NTSB added EMS operations to its “Most Wanted” list, the Board members voted unanimously (5-0) to remove fuel tank safety from the list of needed actions. In the wake of the TWA flight 800 center wing tank fuel/vapor explosion of July 1996, which killed all 230 aboard, the NTSB issued a recommendation on 13 December 1996 recommending that all transport planes be equipped with nitrogen inerting systems. By filling the void spaces in fuel tanks with nitrogen-enriched air, the evanescent presence of a spark or other ignition source would not cause the sort of massive explosion that downed the TWA B747.

“This issue was on our ‘Most Wanted’ list for more than a decade,” said NTSB Chairman Mark Rosenker. “Our most wanted list did its job.”

Well, not quite. The original NTSB recommendations called for inerting of all tanks, not just center wing tanks with heat-generating equipment below them; the original recommendations also called for carrying a minimum amount of fuel to limit the potential for the temperature limits of center tanks to be exceeded, and the recommendations called for a tank-temperature display in the cockpit.

The FAA never did implement the urgent recommendation regarding the carriage of additional fuel until inerting technology was available. The FAA has not called for a tank temperature display in the cockpit. Indeed, the agency also has not mandated an oxygen sensor or cockpit display of oxygen concentration in the tanks to ensure that the nitrogen inerting system is in fact working to adequately protect the tanks from explosive vapors.

The FAA is limiting its mandate for inerting to center wing tanks with heat generating equipment below them. The NTSB called for inerting all fuel tanks, regardless of the presence of heat sources nearby. For example, the NTSB recommended the inerting of wing, tail and auxiliary fuel tanks, not just center wing tanks.

The fuel tank explosion in 2006 in the wing of a Transmile B727 on the ground at Bangalore, India, supports the NTSB’s call for inerting of all fuel tanks, not just center tanks with heat sources below them. In the case here, wires arced in a conduit inside the tank. As the NTSB said, “This accident illustrates that ignition sources continue to exist and fuel tank explosions continue to occur in both wing and center wing fuel tanks despite the corrective efforts of government regulators and industry.”

The fuel tank explosion in 2006 in the wing of a Transmile B727 on the ground at Bangalore, India, supports the NTSB’s call for inerting of all fuel tanks, not just center tanks with heat sources below them. In the case here, wires arced in a conduit inside the tank. As the NTSB said, “This accident illustrates that ignition sources continue to exist and fuel tank explosions continue to occur in both wing and center wing fuel tanks despite the corrective efforts of government regulators and industry.”

 

 

 

 

 

 

 

 

 

 

 

 

 

 

This more comprehensive approach to fuel tank safety (inerting plus mitigation of all ignition sources) has not been adopted.

The rule published by the FAA affects about 5,000 new and existing airplanes. The number of airplanes is about 800 less than originally proposed by the FAA, indicating a decision not to retrofit the oldest airplanes – the reduced fleet size was either not recognized by the NTSB, or the Board simply preferred not to discuss it.

While the FAA’s ruling came about 12 years after the TWA flight 800 disaster, it provides an additional ten years before a compulsory fix on existing planes is made. That is, the last airplanes covered by the FAA’s ruling can fly without modification until 2018 – fully 22 years after TWA flight 800 exploded. (For a detailed discussion of the FAA’s final ruling on fuel tank safety, see Aviation Safety & Security Digest, ‘Significant Regulatory & Related Activity,’ archive, August 2008.)

The NTSB did register minor objections to the FAA’s action. In a 16 October 2008 letter to Acting FAA Administrator Robert Sturgell, Rosenker said:

“The Safety Board notes that a level of risk remains, especially in the wing/unheated tanks; however, the FAA has examined the risk and evaluated it to be within the limits for acceptable risk in 14 Code of Federal Regulations Section 25.1309.”

That section says the following:

§ 25.1309 Equipment, systems, and installations

“(a) The equipment, systems, and installations whose functioning is required by this subchapter, must be designed to ensure that they perform their intended functions under any foreseeable operating condition …

“(c) Warning information must be provided to alert the crew to unsafe system operating conditions ….”

Neither case applies to wing/unheated tanks, as electrical components inside unheated wing tanks still pose an ignition source, and pilots do not have a cockpit indicator of temperature inside any fuel tank. The NTSB interpretation of Section 25.1309 is generous to the point of being delusional.

But then, even with its “Most Wanted” recommendations, the NTSB said nothing when the FAA made the distinction between unheated and heated fuel tanks. The NTSB remained silent as the FAA proceeded without any provisions for cockpit monitoring of tank temperature or inerting.

The lack of aggressive NTSB follow up has abetted a minimalist FAA response. Rosenker’s 16 October letter says Safety Recommendation A-96-174 is classified “Closed – Acceptable Action” and thanks the FAA for its “persistent efforts” to enhance fuel tank safety.

If this is an example of the “Most Wanted” list doing its job, as Rosenker announced, his remark may persuade the trusting public but it is grievously misleading. Only in the most limited sense – heated center wing tanks – has the FAA acted, specifying inerting as an enhancement to safety, and not as an essential part of the defenses in depth against another fuel tank explosion. Such a definition would have meant two inerting units so that if one were inoperative the remaining unit would still provide the requisite flow of nitrogen enriched air. Thus, even after the last airplane is retrofitted in 2018, airplanes with heated center wing tanks can fly for up to ten days with their lone inerting system inoperative, awaiting repair, under the rules governing an airplane’s Minimum Equipment List (MEL).

The NTSB could have been justified in closing its recommendation as “Acceptable Partial Action,” because the FAA has not mandated inerting for all fuel tanks, all the time. Nor is Section 25.1309 of the Federal Aviation Regulations in any way complied with, because flight crews are kept ignorant of the temperature and inerting status of their fuel tanks.

The real reason fuel tank inerting was removed from the “Most Wanted” list is because the NTSB has not carried out diligent follow-through over the last ten years and because the limited FAA ruling issued last July is about all that can be gotten at this point.

A detailed listing of the now-extant “Most Wanted” recommendations follows:

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