|Title:||Pitch control problems, BAe 146-200, G-JEAX, December 12, 2002|
|Micro summary:||This BAe 146-200 experienced pitch control difficulties on climb.|
|Event Time:||2002-12-12 at 1309 UTC|
|Publishing Agency:||Aircraft Accident Investigation Board (AAIB)|
|Publishing Country:||United Kingdom|
|Site of event:|
|Departure:||Birmingham International Airport, West Midlands, England|
|Destination:||George Best Belfast City Airport, Belfast, Northern Ireland|
|Airplane Type(s):||BAe 146-200|
|Operator(s):||British European Airways|
|Type of flight:||Revenue|
|Executive Summary:||The aircraft had been parked overnight on the apron at Belfast City Airport. At 0200 hrs it was anti-iced with undiluted Type II+ fluid in preparation for a departure to Birmingham at 0655 hrs. At 0555 hrs the crew reported at Belfast City for a four sector duty, shuttling between Belfast and Birmingham. |
The first three sectors proceeded without incident and the aircraft arrived at Birmingham, for the second time, at 1145 hrs. The synoptic situation at 1200 hrs showed high pressure centred over Norway with a light south-easterly flow over the route between Birmingham and Belfast. Frontal systems affected the southern half of the UK producing a mixture of rain and snow over the Midlands. This precipitation was falling from multiple layers of cloud, which had a base at about 1,000 feet. The UK Low Level Forecast for the route warned of severe icing in freezing rain and moderate icing in cloud.
The aircraft remained on stand at Birmingham for 55 minutes. During this time a mixture of rain, sleet and snow fell. The commander and co-pilot discussed the need to de-ice the aircraft, but decided that the snow was not settling on the airframe and that it would not be necessary. The aircraft pushed back off stand at 1240 hrs. During the full and free check of the controls, prior to takeoff, the control column was held fully back for about 25 seconds to allow any excess water to drain from the elevator. This was in accordance with standard operating procedures.
The aircraft took off at 1252 hrs and followed the Whitegate 3E Standard Instrument Departure. The commander flew the aircraft manually until it had reached approximately 3,000 feet, when he engaged the autopilot. ATC instructions enabled the crew to maintain a continuous climb. The crew activated the aircraft's anti-ice systems as appropriate but were not aware of any significant accumulations of ice during the flight. The aircraft cleared the tops of the clouds at about 18,000 feet.
During the climb, the flight crew noticed that the aircraft was oscillating in pitch more than was customary. Minor pitch oscillations with the autopilot engaged are not an unusual feature of the aircraft type but the oscillations were unusually pronounced on this sector. The autopilot remained engaged for significant portions of the climb but the level-off at FL 240 was flown manually. Shortly after establishing level flight, the autopilot was re-engaged but the aircraft began to oscillate in pitch and diverge from its assigned flight level. The commander disengaged the autopilot and was immediately aware of a strong pitch-up tendency. He applied an increasing forward pressure on the control column and supplemented this with electric elevator trim in the nose-down sense. At FL 242 the aircraft was reported to have pitched down at a marked rate. Having pitched to below the straight and level attitude, the commander then tried to counter this with a progressive rearwards force on the controls. He described the feel of the control forces as very heavy but did not regard the controls as jammed. Unable to arrest the aircraft's rate of descent, the commander instructed the co-pilot to assist him on the control column. They both pulled back with considerable force. The control column suddenly moved aft, the aircraft pitched up and the flight crew felt a violent shudder through the whole airframe that lasted for two or three seconds. After this, the crew stated that the control forces returned to normal and they were able to level the aircraft at FL 240.
During the pitching manoeuvres, two of the three cabin crew had fallen in the cabin aisle. One of them had sustained a broken leg and the other had a suspected sprained ankle. This latter injury was subsequently diagnosed as a fracture. The third cabin attendant and a passenger, who were both seated, had suffered minor head injuries. Two doctors, who were among the passengers, attended the cabin attendant with the broken leg.
The crew transmitted a PAN call, requesting gentle turns and a continuous shallow descent. Control of the aircraft was handed to the co-pilot while the commander managed the aftermath of the event. At 10 nm on final approach to Belfast City Airport the commander resumed control of the aircraft. The landing on Runway 04 was completed without further incident and the aircraft was met by the Emergency Services.
From the time that the crew felt the control forces return to normal at FL 240 the aircraft had been flown manually. Both pilots described the control forces and aircraft response as normal for the remainder of the flight.
|Learning Keywords:||Operations - Upset - Uncommanded or excessive Pitch|
|Systems - Flight Control System|
|Close match:||Pitch control problems, Boeing 747-436, G-BNLB|
|Loss of Pitch Control on Takeoff, Emery Worldwide Airlines, Flight 17, McDonnell Douglas DC-8-71F, N8079U, Rancho Cordova, California, February 16, 2000|
|Elevator failure, Douglas DC-8-71, March 11, 1997|
|Severe pitch oscillations, McDonnell Douglas MD-11, November 25, 2000|
|Elevator control problems, Boeing - Canada (de Havilland) DHC-8-102, March 12, 2000|
|Pitch control problems, Boeing 767-300, March 27, 2001|
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