NTSB Faults Pilot Compliance, Gust Lock in GIV Crash

 - September 9, 2015, 12:15 PM
The gust lock is at the center of the findings of a May 2014 Gulfstream IV crash that killed seven. (Photo: AIN)

The NTSB is issuing a safety alert to underscore the importance of following checklist procedures and is asking NBAA to analyze data to determine the extent of procedural noncompliance in business aviation after the investigation into the crash of a Gulfstream IV on May 31 last year revealed that the pilots did not verbalize any checklist before the accident flight and that a flight control check had not been completed on 98 percent of the previous 175 flights in the airplane.

During a September 9 meeting on the probable cause of the accident, the NTSB also called on the FAA to require modification of the gust lock system on the GIV, which was found to permit throttle movement that was three to four times the design intent. 

The GIV, N121JM, overran Runway 11 during a rejected takeoff at Hanscom Field in Bedford, Mass., killing all seven people aboard. The flight data recorder revealed the aircraft began its takeoff roll with the gust lock engaged but that the crew had not verbalized any of the requisite checklists or performed a flight control check that could have discovered that the gust lock was engaged.  

The NTSB found that the “flight crew’s omission of a flight control check before the accident takeoff indicates intentional, habitual noncompliance with standard operating procedures.” The NTSB further found that the flight crew delayed initiating a rejected takeoff until the accident was unavoidable.

During the post-accident investigation, Gulfstream discovered that the gust lock system, “while limiting movement when engaged, did not achieve its stated six-degree throttle movement limitation.” A subsequent investigation of gust lock systems on nine GIVs revealed that none met the design intent and each demonstrated 18- to 23-degree throttle movement (three to four times the design intent).

The Board noted that while Gulfstream had met certification requirements for the system, it had relied on engineering drawings for certification. Gulfstream is redesigning the gust lock mechanism to ensure it meets the design intent and released two maintenance advisories to operators.  

“We appreciate the NTSB’s commitment to this investigation,” Gulfstream said in a statement after the board meeting, noting it is “actively working with the FAA to modify the lock.” Gulfstream was not ready to indicate when the modification will be available, but a spokeswoman said the modification is in certification flight-test.

The Safety Board cited as the probable cause of the accident “the flight crewmembers’ failure to perform the flight control check before takeoff, their attempt to take off with the gust lock system engaged, and their delayed execution of a rejected takeoff after they became aware that the controls were locked.” The NTSB further cited “habitual noncompliance” with checklists, Gulfstream’s failure to ensure that the gust lock/throttle lever interlock system would prevent an attempted takeoff with the gust lock engaged and the FAA’s failure to detect the inadequacy during certification of the GIV.

Most-Wanted Improvement

The NTSB made five recommendations as a result of the accident, including one to the NBAA to work with flight operational quality assurance groups to analyze existing data for noncompliance with requisite flight control checks. The Safety Board further is recommending that the International Business Aviation Council amend IS-BAO auditing standards to verify that operators are in compliance with best practices for checklist execution. 

“Compliance with checklists, standard operating procedures and company policies–referred to as ‘procedural compliance’–is critical to safe aviation,” said NTSB vice chairman Bella Dinh-Zarr, adding, “This is not the first accident in which our investigators have found procedural noncompliance.” In fact, procedural compliance is on the Safety Board’s Most Wanted List of needed transportation safety improvements, Dinh-Zarr noted.

“There are so many elements of this accident that really bother me,” said NTSB board member Robert Sumwalt. “There are things here that I cannot wrap my head around.” He noted the pilots were operating a “top-of-the-line” business jet, had stable employment, were well qualified with a combined 29,000 flight hours and more than 4,000 in type, and did their training at FlightSafety International. Further, the flight department had received IS-BAO Stage 2 recognition, the chief pilot was described as “meticulous” about aircraft maintenance and the flight manual was “remarkably well written.” But he noted an adage that “You can fool the auditors, but you can never fool yourself” and said, “If you are not performing checklists, you are fooling yourself.”

Dinh-Zarr further emphasized, “This accident was preventable. It could have been avoided by following established procedures.” The Safety Board agreed to issue the safety alert, which she said would bring “everyone’s attention to the critical need to follow checklists to prevent procedural omissions such as failing to remove flight control locks and the need to perform flight control checks before every takeoff.”

The NTSB’s recommendations to NBAA and IBAC are not especially unusual. The safety agency frequently will turn to the associations for assistance on safety issues that may require community outreach. The Safety Board has directed 10 toward NBAA, and all have been addressed in the past, the association said. The association said it “stands ready” to work on the latest recommendation. “Procedural compliance with checklists, standard operating procedures, regulations and company policies is critical to aviation safety,” said NBAA president and CEO Ed Bolen.

NBAA began making plans to reach out to members with flight operations quality assurance (FOQA) programs to develop means to track trends in pre-flight checks. While conceding that FOQA programs will not provide a complete picture of compliance, Mark Larsen, NBAA senior manager of safety and flight operations, said it is the best available means to gather the data.

The accident has heightened interest in compliance and professionalism, but Larsen said those were already among the top safety issues for the association. “It has been a topic of intense interest,” Larsen said, both among its safety committee and its broader membership. The association plans to focus on these concerns at a new National Safety Forum planned on November 19 in conjunction with its annual convention. Among the scheduled speakers is NTSB chairman Chris Hart, who recused himself from the Board deliberations on the Gulfstream accident because he has a family member who works at Gulfstream.

As far as the IBAC recommendation goes, Larsen noted that the associations held a call the day after the Board meeting to discuss how best to address the recommendation. Any change would take place through the IS-BAO Standards Board, which next meets in November.

Aside from the focus on pre-flight checklists, the Board also called on the FAA to require GIV operators to incorporate the modified GIV gust lock system once Gulfstream has completed the redesign and to issue guidance on appropriate use and limitation of the review of engineering drawings to demonstrate compliance with certification regulation. A final recommendation involved identification of nonfrangible structures outside a runway safety area.