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Safety Recommendation Details

Safety Recommendation A-15-031
Details
Synopsis: On May 31, 2014, about 2140 eastern daylight time, a Gulfstream Aerospace Corporation G-IV, N121JM, registered to SK Travel, LLC, and operated by Arizin Ventures, LLC, crashed after it overran the end of runway 11 during a rejected takeoff at Laurence G. Hanscom Field (BED), Bedford, Massachusetts. The airplane rolled through the paved overrun area and across a grassy area, collided with approach lights and a localizer antenna, passed through the airport’s perimeter fence, and came to a stop in a ravine. The two pilots, a flight attendant, and four passengers died. The airplane was destroyed by impact forces and a postcrash fire. The corporate flight, which was destined for Atlantic City International Airport, Atlantic City, New Jersey, was conducted under the provisions of 14 Code of Federal Regulations (CFR) Part 91. An instrument flight rules flight plan was filed. Night visual meteorological conditions prevailed at the time of the accident. The NTSB determines that the probable cause of this accident was 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. Contributing to the accident were the flight crew’s habitual noncompliance with checklists, Gulfstream Aerospace Corporation’s failure to ensure that the G-IV gust lock/throttle lever interlock system would prevent an attempted takeoff with the gust lock engaged, and the Federal Aviation Administration’s failure to detect this inadequacy during the G-IV’s certification.
Recommendation: TO THE FEDERAL AVIATION ADMINISTRATION: After Gulfstream Aerospace Corporation develops a modification of the G-IV gust lock/throttle lever interlock, require that the gust lock system on all existing G-IV airplanes be retrofitted to comply with the certification requirement that the gust lock physically limit the operation of the airplane so that the pilot receives an unmistakable warning at the start of takeoff.
Original recommendation transmittal letter: PDF
Overall Status: Open - Acceptable Response
Mode: Aviation
Location: Bedford, MA, United States
Is Reiterated: No
Is Hazmat: No
Is NPRM: No
Accident #: ERA14MA271
Accident Reports: ​Crash on takeoff of Gulfstream Aerospace Corporation G-IVRunway Overrun During Rejected Takeoff, Gulfstream Aerospace Corporation G-IV, N121JM
Report #: AAR-15-03
Accident Date: 5/31/2014
Issue Date: 9/24/2015
Date Closed:
Addressee(s) and Addressee Status: FAA (Open - Acceptable Response)
Keyword(s):

Safety Recommendation History
From: NTSB
To: FAA
Date: 3/14/2017
Response: e note that Gulfstream developed the modifications to the G IV gust lock system, and that you approved these revisions. On December 12, 2016, you published a notice of proposed rulemaking (NPRM), “Airworthiness Directives; Gulfstream Aerospace Corporation Airplanes,” at 81 Federal Register 89397. The NPRM proposed to adopt a new airworthiness directive (AD) for all Gulfstream Aerospace Corporation Model G-IV airplanes that would require the gust lock system modification and a maintenance or inspection program revision to incorporate functional tests. On January 11, 2017, in our comments on the NPRM, we said that if the proposed AD were issued, it would satisfy our recommendation. Pending issuance of the AD, Safety Recommendation A-15-31 remains classified OPEN--ACCEPTABLE RESPONSE.

From: FAA
To: NTSB
Date: 2/2/2017
Response: -From Michael P. Huerta, Administrator: On May 23, 2016, the Federal Aviation Administration (FAA) completed the certification effort for the modification to the G-IV gust lock/throttle lever interlock system that complies with Title 14, Code of Federal Regulations§ 25.679(a)(2). The gust lock will physically limit the operation of the airplane so that the pilot receives an unmistakable warning at the start of takeoff. The modification restores the original design intent of the G-IV gust lock/throttle lever interlock to limit the throttle movement to no more than 6 degrees. Additionally, the modification was defined and validated through the FAA certification process which utilized ground tests to verify the efficacy of the design. Also, Gulfstream issued G-IV Customer Bulletin (CB) Number Rev 236A, dated August 8, 2016, to incorporate the approved modification on all existing G-IV airplanes with the intent that the CB will be mandated by an FAA Airworthiness Directive (AD). The FAA has since started the process to issue a notice of proposed rulemaking AD that will propose to mandate retrofit of the gust lock/throttle lever interlock system and include a repetitive inspection of its functionality. At this time, Gulfstream is advising its operators to incorporate the modification prescribed by CB Number 236 within 36 months from the issue date of the CB. Gulfstream also has incorporated the repetitive inspection associated with the modification in their instructions for continued airworthiness as temporary revisions to the G-IV aircraft maintenance manual. I will keep the Board informed of the FAA's progress on this recommendation and provide an update by April 2017.

From: NTSB
To: FAA
Date: 1/11/2017
Response: The National Transportation Safety Board (NTSB) has reviewed the Federal Aviation Administration’s (FAA) notice of proposed rulemaking (NPRM) titled, “Airworthiness Directives; Gulfstream Aerospace Corporation Airplanes,” which was published at 81 Federal Register 89397 on December 12, 2016. The NPRM proposes to adopt a new airworthiness directive (AD) for all Gulfstream Aerospace Corporation Model G-IV airplanes. This proposed AD would require modification of the gust lock system and a revision of the maintenance or inspection program to incorporate functional tests. The FAA is proposing the AD to address an unsafe condition on these products. According to the FAA, “this proposed AD was prompted by a report indicating that the G-IV gust lock system allows more throttle travel than was intended and could allow the throttle to be advanced to reach take-off thrust.” The NTSB investigated the May 31, 2014, accident involving a Gulfstream Aerospace Corporation G-IV, N121JM, registered to SK Travel, LLC, and operated by Arizin Ventures, LLC, which crashed after it overran the end of runway 11 during a rejected takeoff at Laurence G. Hanscom Field, Bedford, Massachusetts.2 The airplane rolled through the paved overrun area and across a grassy area, collided with approach lights and a localizer antenna, passed through the airport’s perimeter fence, and came to a stop in a ravine. The two pilots, a flight attendant, and four passengers died. The airplane was destroyed by impact forces and a postcrash fire. The NTSB’s investigation determined that the crew attempted to take off with the gust lock system engaged. Further, although the gust lock system design included a feature to restrict throttle lever movement to 6 degrees to provide an unmistakable warning that the gust lock system was engaged, it did not operate as intended. Postaccident testing on nine in-service Gulfstream G-IV airplanes found that, in each case, the gust lock system allowed throttle lever movement 3 to 4 times greater than the intended 6 degrees when the gust lock system was engaged. We determined that Gulfstream Aerospace Corporation’s “failure to ensure that the G-IV gust lock/throttle lever interlock system would prevent an attempted takeoff with the gust lock engaged” was a contributing factor to the accident and issued Safety Recommendation A-15-31, which asked the FAA to do the following: After Gulfstream Aerospace Corporation develops a modification of the G-IV gust lock/throttle lever interlock, require that the gust lock system on all existing G-IV airplanes be retrofitted to comply with the certification requirement that the gust lock physically limit the operation of the airplane so that the pilot receives an unmistakable warning at the start of takeoff. On March 15, 2016, we classified Safety Recommendation A-15-31 “Open—Acceptable Response,” pending action from the FAA to mandate a retrofit for the G-IV fleet. We believe that the proposed AD will help to ensure that the gust lock system will provide an unmistakable warning to the flight crew when it is engaged. This safety feature, when operating as intended, can provide an important layer of protection and help prevent pilots from attempting to take off with the gust lock engaged. If the proposed AD is issued, it will satisfy Safety Recommendation A-15-31. The NTSB fully supports the proposed AD and appreciates the opportunity to comment on this NPRM.

From: NTSB
To: FAA
Date: 3/15/2016
Response: We note that, once Gulfstream has fully defined and validated the modifications to the G IV gust lock system, you intend to mandate the retrofit for the G-IV fleet. Pending future updates on your progress, Safety Recommendation A-15-31 is classified OPEN—ACCEPTABLE RESPONSE.

From: FAA
To: NTSB
Date: 12/9/2015
Response: -From Michael P. Huerta, Administrator: The FAA has been working with Gulfstream Aerospace Corporation to develop corrective actions for the Gulfstream G-IV gust lock system since June 2014. As soon as Gulfstream has fully defined and validated these modifications, the FAA will initiate airworthiness action to mandate the retrofit for the G-IV fleet. The latest schedule indicates the design modifications will be available in March 20 16.