Safety Recommendation A-01-013

At the February 3 meeting, the FAA indicated that it surveyed all U.S. operators of Boeing 737s that have the subject jumpseat installed to determine any other instances of loose bolts or seat failure. The survey found that the only occurrence of a pivot bracket failure was during the March 5, 2000, accident in Burbank. The FAA also indicated that Southwest Airlines inspects aircraft every 440 days in accordance with AD 89-14-11, which requires visual inspections of the jumpseat rollers, located in the vicinity of the pivot bracket. Southwest Airlines updated its task cards used for these inspections to include inspecting for loose bolts and damaged/cracked pivot brackets.

The FAA's action, described at the February meeting, of surveying all U.S. operators of affected aircraft and determining that only one operator had a problem and Southwest Airlines' action of updating the task cards to include an inspection for loose bolts and damaged/cracked pivot brackets are an acceptable alternative to the recommended AD. Therefore, Safety Recommendation A-01-13 is classified "Closed--Acceptable Alternate Action."

The FAA reviewed the design of the Trans Aero Industries Model 90835 jumpseat along with the NTSB supplied pictures of the actual failed pieces from the incident aircraft The failure of the pivot bracket was more likely due to the combination of forces experienced in the accident in conjunction with the force of the escape slide that inflated inside the cabin and wound up on top of the seated attendants (see NTSB Safety recommendation A-01-12, Slide Cover Latch Brackets. The FAA has mandated AD 2004-02-08 to address the escape slide).

While seats are designed to protect its occupants and withstand the loads associated with an emergency landing, they are not designed to take the additional loads imparted by a malfunctioning slide. The following observations support this conclusion: · The attendant seat pivot bracket does not appear to be damaged in and around the two mounting fasteners as would be expected if the loose bolts contributed to the failure, i.e., torn out holes; · The only damage to the pivot bracket is found where the force was transmitted into the pivot bracket from the jumpseat by its support arm assembly and from the forces experienced in the accident;

· The bracket that failed was on the side of the jumpseat closest to the inflated escape slide and would have experienced higher forces imparted onto the jumpseat by the slide. Nonetheless, all of the US operators that have the subject jumpseat installed on their Model 737 aircraft received from Boeing were surveyed to determine any other instances of loose bolts or seat failure. In addition to Southwest, these airlines include Delta. America West, US Airways and United. All but one of the airlines provided responses in November 2001. We have recently received information from America West that now brings us to 100% response.

Boeing informed us that all of the airlines reviewed their maintenance records and difficulty reports. Southwest and America West both informed us that, in responding to the survey, that they reviewed their maintenance logs and difficulty reports for loose pivot bracket bolts and/or failed seats. No physical inspections of seats were performed in responding to the survey. The feedback received from these airlines indicates that the pivot bracket wear and looseness of pivot bracket attachment hardware was isolated to Southwest Airlines and the pivot bracket failure to this specific aircraft.

While it is not clear why Southwest Airlines is the lone operator and this is the lone aircraft to have encountered this failure, the condition is most likely maintenance related. As a side note, US Airways has not experienced such wear and looseness in any of their seats that are inspected through their seat shop where the seats are routinely checked for such conditions. Furthermore, we have verified that Southwest Airlines performs an inspection every 440 days to satisfy the requirements of AD 89-14-11 This AD requires visual inspections of the jumpseat rollers, which are located in the vicinity of the pivot bracket.

SWAT Meeting: The FAA indicated that it had done a survey of operators that had Trans Aero Industries Model 90835 jumpseats installed on their aircraft. The FAA asked them to check if the subject bracket was worn or loose, or had experienced a failure. The FAA found that with the exception of Southwest Airlines, no other carrier had any worn or loose brackets. Southwest now has a program to inspect these brackets regularly to ensure that they are tight. The Safety Board asked when the survey was done, and what other carriers it covered. The FAA did not have that information at the meeting, but indicated that it would get it.

Results The FAA will provide information on the survey done, and the results found, including the inspection program at Southwest Airlines. When this information is received, this recommendation will be classified "Closed-Acceptable Alternate Action."

Letter Mail Controlled 8/7/2003 11:14:30 AM MC# 2030383 The Federal Aviation Administration (FAA) has reviewed the design of the Trans Aero Industries Model 90835 jumpseat along with the picture provided by the Board of the actual failed pieces from the incident aircraft. The FAA has concluded that the looseness of the pivot bracket mounting bolts did not contribute to the failure of the pivot bracket. The FAA has determined that the failure of the pivot bracket was due to the combination of forces experienced in the accident in conjunction with the force of the inflated escape slide that was on top of the seated attendants.

The FAA based its conclusion on the fact that the pivot bracket does not appear to be damaged in and around the two mounting fasteners and the only damage to the pivot bracket is where the force was transmitted into the pivot bracket from the jumpseat by its support arm assembly. In addition, the bracket that failed was on the side of the jumpseat closest to the inflated escape slide and would have experienced higher forces imparted onto the jumpseat by the escape slide.

Based on the above analysis and a review of the service history, the FAA has determined that the subject jumpseat failure is an isolated incident. Therefore, regulatory action to require inspections or a design change is not warranted. I believe that the FAA has satisfactorily responded to this safety recommendation, and I look forward to your response.

The Safety Board is concerned that the FAA may not have analyzed the part that failed in the Southwest Airlines flight 1455 accident. Enclosed is a picture of the actual pieces (and their part numbers) that failed. The Board believes that the FAA analyzed failures of the parts identified as the pivot arm and castellated nut and cotter pin. However, the picture shows that the part that failed was the pivot bracket (into which the pivot arm fits when assembled) and that this part failed due to the looseness of the pivot bracket mounting bolts.

This recommendation asks for inspection of the entire pivot bracket assembly, including bracket mounting including bolts, and tightening, if necessary. The Board asks the FAA to reconsider its decision that no action is warranted. Pending the recommended action, Safety Recommendation A-01-13 is classified "Open--Unacceptable Response."

Letter Mail Controlled 01/03/2002 2:16:29 PM MC# 2020009 The FAA reviewed the design of the flight attendant jumpseat with The Boeing Company and the seat manufacturer. According to The Boeing Company, the Trans Aero Model 90835 jumpseat was last delivered in 1996 and was installed on America West, Delta Airlines, USAirways, United Airlines, and Southwest Airlines airplanes (Southwest Airlines has the majority of these seats). The FAA has reviewed copies of Southwest Airlines' maintenance discrepancy reports of pivot bracket assemblies on these jumpseats from the past 2 years.

Based on the FAA's review of these reports, it has concluded that the looseness of the pivot bracket assembly that was observed on the accident airplane was an isolated event. The Boeing Company has also surveyed all of the above-mentioned airlines and found no other reports of loose bolts or seat failure outside of the accident airplane. The FAA has also reviewed the design of the failed seat and found that the pivot bracket mounting bolt requires a castellated nut with a cotter pin keeper that does not allow the bolt to become loose. The FAA believes that if the bolt were to come loose, it still would not cause the seat failure as seen on the accident aircraft.

The FAA concludes that the seat pivot bracket failed due to the combination of the forces experienced in the accident, along with the escape slide inflating into the jumpseat. Consequently, regulatory action is not warranted, and the FAA considers its action be completed in response to this safety recommendation.

The FAA reports that it is reviewing the design of the jumpseat with the Boeing Company and the seat manufacturer to determine the appropriate course of action to address this safety recommendation. Pending the results of the FAA's review, and the issuance of an AD, Safety Recommendation A-01-13 is classified "Open--Acceptable Response."

Letter Mail Controlled 06/26/2001 10:10:14 AM MC# 2010516 The FAA is reviewing the design of the jump seat with The Boeing Company and the seat manufacturer to determine the appropriate course of action to address this safety recommendation. We anticipate completing the review by October 2001. I will inform the Board of the FAA's actions to address this recommendation as soon as the review is completed.