NEW YORK, NY, USA
N833BE
British Aerospace RJ-70
The Avro RJ-70 was on approach, about 1500 ft agl, with the auto-pilot engaged, when it encountered wake turbulence from a preceding Airbus 340 and rolled left. The flying pilot, who occupied the right seat, reached for the yoke to disconnect the auto-pilot and to apply corrective aileron input. He applied large and/or abrupt movement of the ailerons before achieving an auto-pilot disconnect. The ailerons uncoupled, after which, the pilot continued with the approach and landed without further incident. A postincident test revealed that the breakaway forces for the aileron interconnect detent strut were within the manufacturer's specification. The manufacturer reported that movement of the aileron flight controls from the side opposite of the engaged auto-pilot servo could result in an aileron uncoupling. Once uncoupled, the left yoke controlled the left aileron and roll spoiler, and the right yoke controlled the right aileron and roll spoiler.
On July 25, 1995, at 0924 eastern daylight time, an Avro International RJ-70, N833BE, operated by Business Express, Inc., as flight 838, experienced an aileron uncoupling, while on approach to the John F. Kennedy International Airport, Jamaica, New York. The airplane was not damaged, and there were no injuries to the 2 airline transport rated pilots, the 2 flight attendants, or the 20 passengers. Instrument meteorological conditions prevailed. The scheduled passenger flight originated in Cleveland, Ohio, at 0755. An instrument flight plan was filed for the flight which was operated under 14 CFR Part 121. Flight 838 was about 4 miles in trail of an Airbus Industries A340, conducting the VOR approach to runway 13L, and in the vicinity of the Carnasie VOR, when the incident occurred. In a written statement, the flying pilot, who occupied the right seat stated: ...During the approach the aircraft rolled rather abruptly to the left (very little fore warning) the auto pilot was engaged in the heading mode. I grabbed the yoke applying adverse control using a fair amount of force.... Radar data from the New York TRACON was examined by the NTSB Vehicle Performance Division. According to their report, "...the incident occurred at approximately 1323:49 [UTC] radar time. The A340 passed through the area of occurrence about 2000 feet MSL, and the RJ-70 passed through the same area at 1,500 feet MSL, and 118 seconds later. The flight data recorder was examined in the NTSB Laboratory in Washington, D.C. According to the data, the airplane rolled left, followed by aileron input for a right roll. The airplane then rolled past the wings level position, to the right, after which the left aileron went into the trail position, and the right aileron continued to respond to inputs from the right side control yoke. The uncoupling of the ailerons preceded the disconnect of the auto-pilot. A check of FAA, and Avro International records revealed no other inflight occurrences of an aileron interconnect uncoupling. Testing of the control yoke uncoupling forces from both pilot seats, in each direction, was within the limits of 30-39 inch-pounds. In both telephone interviews, and written documentation, Avro International reported that the aileron uncoupling was possible when aileron input was applied from the yoke opposite of the side of the auto-pilot servo engaged, and could occur again. No warnings or notices were found in the flight manual for the possibility of an aileron uncoupling, in other than jammed flight controls; however, no jam was found to have occurred. Once uncoupled, the control yokes were connected to the aileron and roll spoiler on their respective side. The airplane was a continuation of the British Aerospace 146 series. Original certification was handled by the Civil Aviation Authority - United Kingdom. The FAA type certificate was issued based upon original certification, and additional FAA requirements, under provisions of a bilateral agreement between the United Kingdom and the United States.
the aileron interconnect became uncoupled, when an abrupt and/or large aileron movement was made in response to a wake turbulence encounter, while on a VOR approach with the autopilot engaged. A factor relating to the incident was: inadequate in-flight planning/decision by the aircrew, which allowed the wake turbulence encounter.
Source: NTSB Aviation Accident Database
Aviation Accidents App
In-Depth Access to Aviation Accident Reports
