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General Aviation Safety
On June 4, 2007, about 1600 central daylight time, a Cessna Citation 550, N550BP, impacted Lake Michigan shortly after departure from General Mitchell International Airport, Milwaukee, Wisconsin (MKE).1 The two pilots and four passengers were killed, and the airplane was destroyed. The airplane was being operated by Marlin Air under the provisions of 14 Code of Federal Regulations (CFR) Part 135 and departed MKE about 1557 with an intended destination of Willow Run Airport (YIP), near Ypsilanti, Michigan. At the time of the accident flight, marginal visual meteorological conditions prevailed at the surface, and instrument meteorological conditions prevailed aloft; the flight operated on an instrument flight rules flight plan.
TO THE FEDERAL AVIATION ADMINISTRATION: As an interim measure (pending an available aileron trim system retrofit), notify Citation pilots and operators of the potential hazards related to the sensitivity and responsiveness of the airplane’s aileron trim system.
Original recommendation transmittal letter:
Closed - Unacceptable Action
Milwaukee, WI, United States
Loss of Control and Impact with Water, Marlin Air Cessna Citation 550, N550BP
Addressee(s) and Addressee Status:
FAA (Closed - Unacceptable Action)
Safety Recommendation History
In our investigation of the Marlin Air accident, we found that it was easy to set the aileron trim for the Cessna Citation inappropriately, which inadvertently created a hazardous out of trim condition. Investigators found the control knob for the aileron trim system of the accident aircraft between a half and a full rotation to the left of the neutral (centered) position. The display in a cable-driven system such as that of the Cessna Citation 550 commonly does not move smoothly and will jump slightly as the system moves; a ground test conducted as part of our investigation found that a half-turn of the control knob could result in no change to the displayed setting of the trim system. Therefore, the display of a half turn to the left may have indicated that the system was anywhere between the neutral position and a full turn to the left. The owner of the accident airplane related that the trim was so sensitive that he had been surprised once, after picking up the airplane from maintenance, when, during takeoff, he found that the airplane had a strong tendency to roll and that a half-knob rotation had created the out of-trim condition. This had occurred at slow speed, and he corrected the out-of-trim condition before he allowed the speed, and related control forces, to increase. Accordingly, we issued Safety Recommendation A-09-122, which recommended that the FAA require Cessna to reduce the aileron trim sensitivity on Citation series airplanes. Safety Recommendation A-09-123 addressed the need for an interim action to advise Citation pilots of this hypersensitivity until the response to Safety Recommendation A-09-122 could be completed. In 2011, you reviewed the original flight test data and conducted flight tests of the Cessna Citation to evaluate trim sensitivity. Following these actions, on October 4, 2011, you told us that you had concluded that no changes were required to the aileron trim system of any of the Citation series aircraft, and that you considered your actions in response to Safety Recommendation A-09-122 complete. On January 10, 2012, we replied that, based on our findings from the accident investigation, we disagreed with your conclusion and classified Safety Recommendation A 09 122 “Closed—Unacceptable Action.” In response to A-09-123, which was to be an interim action for A-09-122, on February 4, 2014, you issued Safety Alert for Operators (SAFO) 14001, “Cessna Citation CE 500 Type Aircraft Aileron Trim Systems.” We do not believe that the SAFO satisfies Safety Recommendation A-09-123. Our review found that the SAFO does not adequately describe the sensitivity problems we found during our investigation of the Marlin Air accident and does little more than advise pilots and operators to follow the manufacturer’s recommended procedures for the use of aileron trim. Because you have indicated that you consider your actions complete and you plan no further action, Safety Recommendation A-09-123 is classified CLOSED—UNACCEPTABLE ACTION.
-From Michael P. Huerta, Administrator: In July 2010, Cessna and the Federal Aviation Administration (FAA) conducted flight tests to evaluate the sensitivity of the aileron trim system. These tests found that the aileron trim system• s sensitivity is appropriate for its intended use. The FAA addressed this recommendation by issuing Safety Alert for Operators (SAFO) 14001, Cessna Citation CE-500 Type Aircraft Aileron Trim Systems, on February 4, 2014. This SAFO states that all operators of Cessna Citation CE-500 aircraft should follow the manufacturer's recommended procedures for the use of aileron trim given the complexities of the aileron trim system. SAFO 14001 can be found at the following Web address: http://www.faa.gov/other_visit/aviationindustry/airline_operators/airlinesafety/safo/all_safos/media/2014/SAFO14001.pdf. I believe the FAA has effectively addressed this safety recommendation and consider our actions complete.
The FAA's plan to issue a safety alert for operators (SAFO) that will address the potential hazards related to sensitivity and responsiveness of the Citation's aileron trim system will satisfy this recommendation. Accordingly, pending issuance of the SAFO, Safety Recommendation A-09-123 is classified OPEN – ACCEPTABLE RESPONSE.
Letter Mail Controlled 7/29/2010 4:30:29 PM MC# 2100167 - This incoming letter does not address A-09-123.
Letter Mail Controlled 2/26/2010 4:02:13 PM MC# 2100071 - From J. Randolph Babbitt, Administrator: The FAA will address this safety recommendation by developing and issuing a Safety Alert for Operators (SAFO). The SAFO will address all aircraft operators of Cessna Citation CE-500 series aircraft. The SAFO will also address revising the company's general operations manual (GOM) and standard operating procedures (SOP) to compensate for the potential hazards related to sensitivity and responsiveness of the Citation's aileron trim system. The SAFO will provide guidance on producing a comprehensive training program that will include the proper operation of the Citation's aileron trim system and changes to the operator's GOM and SOP for the use of the aileron trim system. I will provide a copy of the SAFO as soon as it is issued.
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