Crash Investigation Reveals Inconsistent Oversight

The investigation of a cargo airplane crash reveals inconsistencies in the government’s approach to air safety. Both the National Transportation Safety Board (NTSB) and the Federal Aviation Administration (FAA) are open to criticism for being inconsistent. The lack of a uniform approach makes safety improvement difficult, if not impossible.

The case involves the early morning 27 January 2009 crash of Empire Airlines flight 8284, an ATR-42 twin-turboprop, in Lubbock, TX. The airplane was registered to Federal Express and was painted in FedEx colors but was operated by Empire. Flight crews, dispatch and maintenance personnel were all Empire employees.

The accident airplane before the crash

The accident airplane before the crash

The NTSB just recently completed its investigation. The airplane was on an 84-minute flight from Ft. Worth and encountered icing on its flight path. If the pilot flying had maintained adequate airspeed, a safe landing could have been made. However, speed degraded and the stick shaker activated – indicative of an impending stall – just short of the runway. The airplane rolled, crashed and skidded across the tarmac. The captain and first officer were able to escape before the airplane was consumed by fire.

Bottom arrow: first impact. Second arrow: where the airplane came to rest.

Bottom arrow: first impact. Second arrow: where the airplane came to rest.

Aftermath

Aftermath

The NTSB determined that the probable cause of the accident was as follows:

“[The] flight crew’s failure to monitor and maintain a minimum safe airspeed while executing an instrument approach in icing conditions, which resulted in an aerodynamic stall at low altitude. Contributing to the accident were:

1) the flight crew’s failure to follow published standard operating procedures in response to a flap anomaly,

2) the captain’s decision to continue with the unstabilized approach,

3) the flight crew’s poor crew resource management, and

4) fatigue due to the time of day in which the accident occurred and a cumulative sleep debt, which likely impaired the captain’s performance.”

The word fatigue is in italics to emphasize that this factor was not included as a contributing factor in the fiery, fatal crash of Colgan Air flight 3407 at Buffalo, NY in 2009. The Bombardier DHC-8-400 was operating as a Continental Connection flight and crashed about 5 miles from the airport after the stick shaker activated, indicating a very low airspeed approaching stall. All 49 persons aboard the aircraft and one individual on the ground were killed in the fiery impact into a neighborhood. (See Air Safety Journal, February 2010, “General Industry Laxity Criticized in Wake of Colgan Air Crash”)

Despite a spirited debate among the NTSB Board members, pilot fatigue was not elevated to a level of being a contributing factor in the Colgan Air crash investigation, despite ample circumstantial evidence that the crew had not attained adequate rest before the flight. The captain had commuted from Florida to the Newark base, and the first officer had commuted from the West Coast. Neither individual had more than catnaps on a ready room couch before the flight to Buffalo. Despite eloquent pleading from NTSB Chairman Deborah Hersman, the Board voted not to include fatigue as a contributing factor. Yet in the Empire Air crash, in which sleep debt was present – although to a lesser degree than in the Colgan Air accident – fatigue was mentioned.

In a statement appended to the Colgan Air investigation, Hersman cited her concerns about fatigue and the Safety Board’s inconsistency:

“[During] the public Board meeting, I submitted a proposal to the Board to amend the probable cause by adding a fifth contributing factor, specifically that the flight crew members’ fatigue contributed to the accident because they did not obtain adequate rest before reporting to duty. After open discussion, the Board rejected the amendment 2 to 1 …

“Let me explain why I think fatigue, an issue that has been on our Most Wanted List of Transportation Safety Improvements since its inception in 1990, was a factor in this accident. Numerous accident investigations, research data and safety studies show that operators, like the crew in this accident, who are on duty but have not obtained adequate rest present an unnecessary risk to the traveling public. Fatigue results from continuous activity, inadequate rest, sleep loss or nonstandard work schedules. The effects of fatigue include slowed reaction time, diminished vigilance and attention to detail, errors of omission, compromised problem solving, reduced motivation, decreased vigor for successful completion of required tasks and poor communication, and generally results in performance deficiencies like those present during this accident flight. As we conclude in the accident report, the flight crews’ errors, including the captain’s inappropriate response to the activation of the stick shaker and the flight crews’ failure to monitor air speed, adhere to sterile cockpit procedures and adequately monitor the flight, were the causal and contributing factors of this accident. But I also believe that these errors are consistent with fatigue ….

“The failure of the Safety Board to include fatigue as one of the contributing factors in this accident is symptomatic of the Board’s inconsistent [emphasis added] approach to addressing fatigue in transportation accidents. We have developed a methodology to be used by our investigators in our on-going efforts to address fatigue in accident investigations through a fatigue checklist …

fatigue checklist1

fatigue checklist

“There is a consensus at the Safety Board that the flight crew in this accident was likely fatigued, and our accident report makes this conclusion. The factual information in the docket establishes the presence of fatigue for both of these crew members. The captain spent the night before the accident sleeping in the company crew room, where he obtained, at best, 8 hours of interrupted sleep as evidenced by multiple log-ins to the CrewTrac system at 2151 [hours], then 0310 and again at 0726. At worst, it was poor-quality, interrupted sleep of a shorter duration. NASA and other studies show that even in an onboard rest facility with beds available for long haul flight crews, pilots might get three hours of sleep and the quality does not approach ‘home’ sleep. So, conservatively, the captain in this accident obtained 2 fewer hours sleep than his usual sleep and perhaps, significantly less based on the quality of sleep. In addition to this acute sleep loss, he had a cumulative sleep debt of between 6 and 12 hours, which reflected the 2 to 4 hours of sleep debt he accumulated over the course of each of the preceding three nights, two of which were spent in the crew lounge. At the time of the accident, he had been awake at least 15 hours – 3 hours more than the level at which the 1994 NTSB study identified performance degradation in accident flight crews. Finally, the [Buffalo] accident occurred at the time of day when the captain would normally go to sleep.

“The first officer was similarly not properly rested. The night before the accident, she commuted from Seattle to Newark, changing planes shortly after midnight in Memphis, and arriving in Newark at 0630, which was 0300 Seattle time. While she may have experienced cumulative sleep debt, she likely had some acute sleep loss and, in the preceding 34 hours, had only gotten a maximum of 8.5 total hours of sleep – 3.5 hours of which were while travelling overnight cross-country (1 ½ hours from Seattle and 2 hours from Memphis to Newark), and the remaining 5 while resting in the company crew room. However, based on information contained in the docket including an interview of a flight attendant who had a conversation with the first officer during the 1100 hour, the 5 hours of rest in the crew lounge between 0800 and 1300 are questionable. Again, it is not likely that she obtained recuperative sleep in a busy, well-lit crew room.

“Reflective of these facts, the Safety Board accident report concludes that ‘[t]he pilots’ performance was likely impaired because of fatigue…’ However, the report diminishes the significance of this finding when it states that ‘[sic] the extent of their impairment and the degree to which [fatigue] contributed to the performance deficiencies that occurred during the flight cannot be conclusively determined.’ More simply, the report concludes that while fatigue likely impaired the pilots’ performance, because we could not assign fatigue a percent or number, we discount it as a contributing factor of the accident ….

“The tragedy in this accident report [emphasis added; note the focus on the report] is what we uncovered in the investigation, we already knew. The FAA talks about safety being their highest priority. Colgan Air’s slogan was never to compromise safety. The pilots want a safe profession. Yet, if we are serious about safety, we must establish an aviation system that minimizes pilot fatigue and ensures that flight crews report to work rested and fit for duty. Flying tired is flying dangerously, and it is a practice that needs to end.”

No doubt this passionate statement was filed by Chairman Hersman to influence her fellow Board members to be more consistent in their quantification of fatigue as a contributing factor in accidents. In the Lubbock accident, fatigue was cited as a contributing factor. In the Buffalo accident, in which crew fatigue was greater, the probable cause is silent on the matter.

Equally, the FAA must bear the charge of inconsistency. The airplane was not certificated for flight in freezing drizzle, a condition known as supercooled liquid droplets (SLD). Airplanes are certificated for flight in a variety of icing conditions, but not when SLD conditions prevail. For years, the NTSB has urged the FAA to expand the certification envelope to include SLD. The FAA has responded with bureaucratic foot-dragging and pleadings, which translated essentially means that the problem of SLD is “too hard” (not the FAA’s choice of words but one which captures the essence of the FAA’s disclaimer).

The result of the FAA’s inaction is confusion within the airline industry. In Empire’s general operations manual, takeoff and landing in SLD conditions were routinely approved. Based on the manual, the dispatchers at Empire believed the ATR-42 could be dispatched into freezing drizzle.

empire5

As a result, the ATR-42 was operating in SLD conditions with reduced or eliminated safety margins. A flap asymmetry problem, poor crew resource management, and other issues contributed to the crash. The accident was not a direct result of icing; if speed in icing had been maintained, it is likely that a go-around or landing could have been safely conducted.

The issue in this case is the faulty guidance in Empire’s manual — a document which requires FAA approval.

Airframe icing during the flight from Ft. Worth to Lubbock, TX

Airframe icing during the flight from Ft. Worth to Lubbock, TX

During the Lubbock crash investigation, NTSB investigators became aware of an Airplane Performance Monitoring (APM) system developed by the manufacturer, Avions de Transport Régional (ATR).

The system detects effects on the airplane associated with ice and alerts aircrews with a light. Rather than dispatching an airplane based on reported weather, the APM detects effects in real-time on the airplane.

NTSB staffer Timothy Burtch explained, “APM provides crews with very definitive cues about how much icing they are in; it takes the guesswork out.”

As Hersman observed, “APM would have alerted them [the pilots] earlier in the flight.”

The European Aviation Safety Agency (EASA) mandated installation of the APM on ATR-42 and -72 model airplanes in August 2009.

The FAA determined that the APM would not have prevented the Lubbock accident and therefore did not order its installation on U.S. registered ATR-42 and -72 aircraft. In January 2011 the FAA’s Office of Accident Investigation and Prevention provided a “no action” memorandum to the NTSB explaining its decision (extracts follow):

“The APM uses various airplane parameters to determine when airplane performance is significantly worse than expected.

“When a State of Design Airworthiness Authority issues mandatory continued airworthiness information (MCAI) against one of its products, and that product is or is likely to be operated in the U.S., the FAA is obligated to evaluate the MCAI and, prior to issuing a corresponding FAA AD [airworthiness directive], make an independent determination that an unsafe condition exists … As a result of this review, the FAA determined that we will not issue a corresponding FAA AD …

“The APM is not enabled in many portions of the flight envelope. The APM is enabled only when the flaps and gear are fully retracted, and either the ice detector has detected ice or the flight crew has activated the airframe ice protection system …

“Of the three events [of ten used by EASA to justify its AD] where severe icing cues were not noted by the flight crew, in one of the events, two warnings from the APM … occurred simultaneously with the stick shaker … In this instance, not only were the APM warnings too late to be useful, they may also have contributed to confusion by overloading the flight crew with warning messages. In the other two events, an APM alert would not have triggered, had the system been installed.”

The NTSB was not persuaded and recommended that the FAA order retrofit ATR-42 and -72 airplanes with APM “if they are not already so equipped.”

Given the FAA’s stated position on the matter, this NTSB recommendation seems unlikely to be implemented.

Meanwhile, FedEx is designing an APM system for its ATR-42 and -72 airplanes, with installation in 2013. The FAA will be in the position of having to weigh issuance of a supplemental type certificate (STC) for a European system already rejected.

Further, the effort to enhance the certification envelope to include SLD languishes.

All the while, aircraft continue to be dispatched into icing conditions and many in the industry falsely believe they are certificated to safely cope, when in fact there is a great unknown about performance in SLD.

The NTSB and the FAA are both struggling imperfectly to improve safety. The Lubbock crash investigation shows the dimensions of the missed opportunities to correct deficiencies in human fatigue, airframe icing, and other issues for which solutions are evident but not required.