F900, en-route, South of Bucharest Romania, 1999
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|On 14 September 1999, a F900 was subjected to rapid and violent vertical load oscillations, which killed most of the passengers, after incorrect crew response to a minor pitch control malfunction.|
|Actual or Potential
|Airworthiness, Human Factors, Loss of Control|
|Aircraft||DASSAULT Falcon 900|
|Type of Flight||Military/State|
|Intended Destination||Bucharest/Henri Coandă International Airport|
|Take off Commenced||Yes|
|ENR / APR|
|Destination||Bucharest/Henri Coandă International Airport|
|Approx.||Calinesti, near Bucharest|
|Tag(s)||Inadequate Aircraft Operator Procedures|
|Tag(s)||Inappropriate crew response - skills deficiency,|
Inappropriate crew response (technical fault),
|Tag(s)||AP Status Awareness,|
Flight Control Error"Flight Control Error" is not in the list (Airframe Structural Failure, Significant Systems or Systems Control Failure, Degraded flight instrument display, Uncommanded AP disconnect, AP Status Awareness, Non-normal FBW flight control status, Loss of Engine Power, Flight Management Error, Environmental Factors, Bird or Animal Strike, ...) of allowed values for the "LOC" property.,
Temporary Control Loss,
|Contributor(s)||Inadequate QRH Drills|
|Damage or injury||Yes|
|Fatalities||Most or all occupants (7)|
|Causal Factor Group(s)|
On 14 September 1999, a DASSAULT Falcon 900 was subjected to rapid and violent vertical load oscillations, which killed most of the passengers, after incorrect crew response to a minor pitch control malfunction. The incident occurred south of Bucharest, Romania.
Greece's Deputy Foreign Minister, who was standing at the time of the accident, was one of the passengers killed.
This is an extract from the Accident Report published by the Romanian Ministry of Transport Civil Aviation Inspectorate:
"The aircraft performed the flight OAL3838, from Athens to Bucharest as a government flight.
During climb after flap and slats were retracted, the flight crew noticed, on the warning panel, the "PITCH FEEL" light came on. The "PITCH FEEL" warning light, remained continuously ON, during cruise and descent until SLATS were extended.
During descent the Indicated Air Speed (IAS) increased from 240 kts444.48 km/h
to 332 kts614.864 km/h
Approaching FL150, the F/O had a request for a further descent.
Just before FL150 the ATC re-cleared OAL3838 to continue descent to FL50, while PIC briefed F/A about ETA. One second later, A/P disengaged and for the next 1 minute and 36 seconds the aircraft was manually flown by the PIC.
Between FL150 and FL140, for approximately 24 seconds, the aircraft experienced 10 oscillations in pitch axis which exceeded the limit manoeuvring load factor. Maximum recorded values of the vertical accelerations recorded by an accelerometer located in the landing gear bay were: +4.7 g and -3.26 g.
The impact of the unfastened passengers with cabin ceiling and aircraft furniture, due to accelerations occurring during the pitch oscillations caused fatal injuries to 7 passengers, serious injuries to 1 crew member and 1 passenger and minor injuries to 2 passengers.
The investigation identified following causal factors:
- Inadequate risk assessments of the PITCH FEEL malfunctions.
- Overriding of the A/P on the pitch channel by the crew.
- Inappropriate inputs on the control column at high speed and with Arthur unit failed in “low-speed” position leading to Pilot Induced Oscillations.
- Seat-belts not fastened during descent flight phase."
For further information see the full Report published by the Romanian Ministry of Transport Civil Aviation Inspectorate.
- Aviation Safety and Pilot Control: Understanding and Preventing Unfavorable Pilot-Vehicle Interactions, by the US National Academy of Sciences, 1997