During the night of 4th may 2007, the B737-800, registration 5Y-KYA, operating as flight KQA 507 from Abidjan International Airport to Jomo Kenyata International Airport made a scheduled stop over at the Douala International Airport. The weather was stormy. Shortly after take off at about 1000ft, the aircraft entered into a slow right roll that increased continuously and eventually ended up in a spiral dive.
On the 5th May 2007 at approximately 0008hrs, the airplane crashed in a mangrove swamp South-South East of Douala. All 114 occupants on board were killed and the airplane was completely destroyed.
This is the conclusion part of the crash report. Full report in PDF is here bit.ly/dtsaEW (40MB)
Conclusion
3.1 Established Facts
1. It is night time
2. The airplane had a valid C of A; no malfunction is recorded in the ATL
3. The FDR (Flight Data Recorder) indicates the aircraft engines were operating normally.
4. Some differences existed between the B737-700 and B737-800 flight instrument displays
5. The weight and balance are within prescribed limits.
6. The crew had valid licenses and all other required qualifications.
7. Medical factors had no influence on the flight.
8. The crew had been adequately rested.
9. Adequate safety oversight capacity was lacking.
10. There was a steep authority gradient in the cockpit.
11. The crew took off in full awareness of the prevailing meteorological condition on the station and the initial leg of their route.
12. The Principal Meteorological Center at Douala Airport issued special weather reports covering the departure period for KQA507.
13. Air traffic control did not broadcast these special weather reports to KQA507.
14. Air traffic control used the French language to transmit a SPECI to another carrier following a request that was also done in French by the subject carrier.
15. The captain is the pilot flying; he doesn't adhere to SOPs(Standard Operating Procedures); does no cockpit scan, has poor situation awareness and reacted inappropriately in the face of the abnormal situation.
16. The airplane took off without authorization from air traffic control.
17. The airplane has a tendency to roll to the right from lift off; this tendency is easily brought under control by the pilot up to 1000ft.
18. At 1000ft. climbing, the pilot flying releases the flight controls for 55 seconds without having engaged the AP(Auto Pilot).
19. The AP is not effectively engaged when the Captain announces "OK COMMAND".
20. The aircraft speed trim comes into action automatically when the speed variation between actual and commanded becomes excessive.
21. The FO(First Officer) is by nature a reserved person and does not call out the lapses in piloting.
22. There were shortcomings in the way the crew worked as a team.
23. The bank angle of the airplane increases continuously by itself very slowly up to 34 degree right and the captain appears unaware of the airplane's changing attitude (yaw, pitch, roll).
24. Just before the "Bank Angle" warning sounds, the Captain grabs the controls, appears confused about the attitude of the airplane, and makes corrections in a erratic manner, increasing the bank angel to 50 degrees right.
25. At about 50 degrees bank angle, the AP is engaged and the inclination tends to stabilize; then movements of the flight controls by the pilot resume and the bank angle increases towards 70 degrees right. The captain states "We are crashing!" and the FO confirms.
26. A prolonged right rudder input brings the bank angle to beyond 90 degrees. The airplane descends on a spiral dive.
27. The FO calls out to the captain to level the wings by the right, then quickly corrects himself and says with insistence "Left, left, left captain"..
28. The bank angle is reduced to 70 degrees and the airplane hits the ground.
29. No information is given to the crew concerning the state of the runway.
30. The supplier of ground handling services allowed KQA line station staff to perform some already contracted tasks.
31. A waiver granted for the utilization of technical flight personnel with a request for the modification of the operations' manual in part D was submitted.
32. The results of flight checks for technical flight personnel are reported without any complacency, but are not sufficiently exploited by the operator.
33. The ELT broke up on impact and therefore no useful signal was emitted to assist in locating the airplane after the accident.
34. Information to crews was missing on the rolling tendency of the airplane during climb and descent and the elements that induce it including:-
(a). Rudder thermal effect
(b). Manufacture asymmetry
35. Full information in the capability of the Autopilot CWS roll mode including ability to roll the airplane from bank angles of 50 degrees and above back to 30 degrees is not explained in the Boeing flight manual.
36. Shortcomings highlighted in the investigation of this flight are among those reported during previous flight checks for the two pilots.
37. Even though visibility is adequate, it is a dark night with mangrove swamps and no cultural lights or other night visible clues off the takeoff end of the runway. This results in no external visual references outside the windshield after takeoff, which is one of the necessary factors for spatial disorientation.
3.2 Probable Causes
The aircraft crashed after a loss of control by the crew as a result of spatial disorientation (non recognized or subtle type transitioning to recognized spatial disorientation), after a long slow roll, during which no instrument scanning was done, and in the absence of external visual references in a dark night.
Inadequate operational control, lack of crew coordination coupled with the non-adherence to procedures of flight monitoring, confusion in the utilization of the AP have also contributed to cause this situation.
