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On December 7, 2011, about 1630 Pacific standard time, a Sundance Helicopters, Inc., Eurocopter AS350-B2 helicopter, N37SH, operating as a “Twilight tour” sightseeing trip, crashed in mountainous terrain about 14 miles east of Las Vegas, Nevada. The pilot and four passengers were killed, and the helicopter was destroyed by impact forces and postimpact fire. The helicopter was registered to and operated by Sundance as a scheduled air tour flight under the provisions of 14 Code of Federal Regulations (CFR) Part 135. Visual meteorological conditions with good visibility and dusk light prevailed at the time of the accident, and the flight operated under visual flight rules. The helicopter originated from Las Vegas McCarran International Airport, Las Vegas, Nevada, about 1621 with an intended route of flight to the Hoover Dam area and return to the airport. The helicopter was not equipped, and was not required to be equipped, with any on-board recording devices. The accident occurred when the helicopter unexpectedly climbed about 600 feet, turned about 90° to the left, and then descended about 800 feet, entered a left turn, and descended at a rate of at least 2,500 feet per minute to impact. During examination of the wreckage, the main rotor fore/aft servo, one of the three hydraulic servos that provide inputs to the main rotor, was found with its flight control input rod not connected. The bolt, washer, self-locking nut, and split pin (sometimes referred to as a “cotter pin” or “cotter key”) that normally secure the input rod to the main rotor fore/aft servo were not found. The investigation revealed that the hardware was improperly secured during maintenance that had been conducted the day before the accident. The nut became loose (likely because it was degraded)1 and, without the split pin, the nut separated from the bolt, the bolt disconnected, and the input rod separated from the linkage while the helicopter was in flight, at which point the helicopter became uncontrollable and crashed. The NTSB determines that the probable cause of this accident was Sundance Helicopters’ inadequate maintenance of the helicopter, including (1) the improper reuse of a degraded self-locking nut, (2) the improper or lack of installation of a split pin, and (3) inadequate postmaintenance inspections, which resulted in the in-flight separation of the servo control input rod from the fore/aft servo and rendered the helicopter uncontrollable. Contributing to the improper or lack of installation of the split pin was the mechanic’s fatigue and the lack of clearly delineated maintenance task steps to follow. Contributing to the inadequate postmaintenance inspection was the inspector’s fatigue and the lack of clearly delineated inspection steps to follow.
TO THE FEDERAL AVIATION ADMINISTRATION: Require that personnel performing maintenance or inspections under 14 Code of Federal Regulations Parts 121, 135, 145, and 91 Subpart K receive initial and recurrent training on human factors affecting maintenance that includes a review of the causes of human error, including fatigue, its effects on performance, and actions individuals can take to prevent the development of fatigue.
Original recommendation transmittal letter:
Open Acceptable Alternate Response
Las Vegas, NV, United States
Loss of Control Sundance Helicopters, Inc. Eurocopter AS350-B2, N37SH
Addressee(s) and Addressee Status:
FAA (Open Acceptable Alternate Response)
Safety Recommendation History
In your initial response on May 21, 2013, you said that the ACMT rulemaking would satisfy this recommendation. As discussed above, in your current letter, you told us you cancelled the rulemaking, but discussed alternative actions that you believe satisfy Safety Recommendation A-13-3. We note that Title 14 CFR section 145.163 (a)(1) requires Part 145 repair stations to have an approved training program, and that initial and recurrent human factors training is required for training program approval under this section. Guidance for ASIs regarding approving the training program is contained in FAA Order 8900.1, volume 3, chapter 55, section 1, “Review and Approve a Part 145 Repair Station’s Training Program,” and initial and recurrent human factors training is included in the approval requirements for this program. Section 145.163 (a)(1) and the procedures in FAA Order 8900.1 satisfy this recommendation for Part 145 repair stations. Your letter went on to say that Part 121, 135, and 91 subpart K air carriers are “encouraged” to adopt and implement a comprehensive maintenance human factors training program. We note that these programs are accepted but not approved by the FAA through the evaluation process described in FAA Order 8900.1, volume 3, chapter 24, section 2, “Safety Assurance System: Evaluate and Accept a Maintenance Human Factors Training Program.” The evaluation includes a review for a fatigue management program. We believe it likely that if an ASI using the procedures in FAA Order 8900.1 identifies issues with the human factors training in an ACMT program, the ASI will bring the issues to the carrier’s attention, and the carrier is likely to make needed revisions. Therefore, the evaluation process in FAA Order 8900.1 may be an acceptable alternative to the recommended requirement in Safety Recommendation A-13-3. However, this is an acceptable alternative only if the training program accepted by the FAA contains a human factors training component. We do not believe that carriers who operate under parts other than 121 are covered by the SAS. Because Part 135 and Part 91 subpart K carriers are only “encouraged” to include human factors training in their maintenance training programs, we are concerned that such carriers may not actually do so, and that an ASI will not be able to convince them to do otherwise. We ask that you provide more details on your actions to encourage Part 135 and 91 subpart K carriers to include human factors in their aviation maintenance training programs. We are particularly interested in what will be expected of an ASI when a carrier’s program does not contain human factors topics, and in any data that you have demonstrating that your encouragement has been effective in assuring that Part 135 and Part 91 subpart K carriers include human factors in their maintenance training programs. Pending information showing that Part 135 and Part 91 subpart K carriers include human factors components in their maintenance training programs, Safety Recommendation A-13-3 is classified OPEN—ACCEPTABLE ALTERNATE RESPONSE.
-From Michael P. Huerta, Administrator: Overall FAA Comment. In our May 9, 2014, response, the Federal Aviation Administration (FAA) indicated that we had initiated the Air Carrier Maintenance Training Programs rulemaking project and would be issuing a notice of proposed rulemaking to set clear training standards, including on-the-job training and comprehensive human factors training. This rulemaking effort was cancelled in August 2015 due to a lack of accident data to support rulemaking activities. All part 121, 135, and 91 subpart K air carriers are encourage to adopt and implement a comprehensive maintenance human factors training program. Currently these programs are accepted by the FAA through an extensive evaluation process outlined in FAA Order 8900.1, Volume 3, Chapter 24, Section 2, Safety Assurance System: Evaluate and Accept a Maintenance Human Factors Training Program. This extensive evaluation process includes the requirement to review for a fatigue management program. All part 145 repair stations are required to have an approved training program per 145.163 (a)(1). This approval is accomplished per the guidance outlined in FAA Order 8900.1, Volume 3, Chapter 55, Section 1, Review and Approve a Part 145 Repair Station's Training Program. Human Factors initial and recurrent training is a required subject for training program approval under this section. As discussed above in our response to A-04-16, the updates to FAA Order 8900.1 and AC 120-72 will include the addition of an AC for aircraft maintenance fatigue risk management. I will keep the Board informed of the FAA's progress on this safety recommendation and provide an update by April 2017.
Pending issuance of the notice of proposed rulemaking associated with the Air Carrier Maintenance Training Program and, subsequently, issuance of a final rule requiring the training recommended, Safety Recommendation A-13-3 is classified OPEN—ACCEPTABLE RESPONSE.
-From Michael P. Huerta, Administrator: The FAA initiated the Air Carrier Maintenance Training Program rulemaking project in May 2010. The rule intends to ensure the following eight types of training are placed into the carrier's "Approved" maintenance training program: • Initial Training • Aircraft Type Training • Required Inspection Item training • Aircraft Movement Training • On the Job Training • Recurrent Training • Differences Training • Human Factors Training On June 6, 2011, we submitted a draft notice of proposed rulemaking for Executive review outside the Agency. However, the draft was returned to the FAA on December 27, 2011, and placed on hold due to limited rulemaking resources and changes in priorities to address rulemaking activities mandated by the Airline Safety and Federal Aviation Administration Extension Act of2010 (Public Law 111-216) and the Federal Aviation Administration Modernization and Reform Act of201 2 (Public Law 112-95). I will keep the Board informed of the FAA's progress on this recommendation and provide an update by May 2014.
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