Accident Airbus A310-324 7O-ADJ,

ASN Wikibase Occurrence # 321482

Date:	Tuesday 30 June 2009
Time:	01:54
Type:	Airbus A310-324
Owner/operator:	Yemenia Airways
Registration:	7O-ADJ
MSN:	535
Year of manufacture:	1990
Total airframe hrs:	53587 hours
Cycles:	18129 flights
Engine model:	Pratt & Whitney PW4152
Fatalities:	Fatalities: 152 / Occupants: 153
Aircraft damage:	Destroyed, written off
Category:	Accident
Location:	6 km NW off Mitsamiouli - Comoros
Phase:	Approach
Nature:	Passenger - Scheduled
Departure airport:	Sana'a International Airport (SAH/ODSN)
Destination airport:	Moroni-Prince Said Ibrahim In Airport (HAH/FMCH)
Investigating agency:	MoT Comoros
Confidence Rating:	Accident investigation report completed and information captured

Narrative:
A Yemenia Airways Airbus A310-324 passenger plane was destroyed when it struck the water and crashed off shore from the Comoros. The airplane was on approach to Moroni-Prince Said Ibrahim In Airport (HAH) runway 20 following an international flight from San'a International Airport (SAH). Yemenia Airways Flight IY626 had 142 passengers and 11 crew on board. A young girl survived the accident.

Approach
The flight conducted a night-time approach to runway 02, which was to be followed by a visual circle-to-land procedure and land on runway 20.
The aircraft captured the localizer of runway 02 at 01:47 hours local time.
At 01:49:41, the crew began the procedure turn to the left in order to reach the downwind leg. The aircraft was at an altitude of 1280 ft, descending.
At about 800 ft, at 01:50:44, still in descent, the crew disengaged the autopilot, selected a heading of 014° (corresponding substantially to that of the downwind leg) and turned the aircraft to join the downwind leg.
During the turn, the vertical speed increased to -2,000 ft/min. At this point the rate should have been -500 ft/min. It is quite likely that, during the turn, the PF tried to see the runway, which until then he had not been able to see, and was therefore not looking at his instruments.
This descent rate resulted in GPWS alarms.
The crew responded to two SINK RATE alarms, then two PULL UP alarms, by increasing the aircraft's attitude and cancelling the bank. The aircraft regained altitude after reaching a lowest point at 350 ft radio altitude. The PF then resumed the right turn to align with the downwind leg. As in the previous turn, the aircraft was descending again and the vertical speed reached about -1000 ft/min, probably for the same reasons as before. The GPWS THREE HUNDRED and TOO LOW TERRAIN alarms sound. In response to these alarms, the PF increased the aircraft's attitude to 17° nose-up and cancelled the bank; the aircraft reached a new low point at 160 ft radio altitude. Except when the turn is established, it seems that, in this phase, the actions of the PF are consistent with the Flight Director indications both laterally and vertically. The crew appears not to have been aware that the vertical mode was unsuitable for their trajectory objective for the visual manoeuvre. The GPWS alarms made the crew aware of their low height. However, they did not apply the procedure following a GPWS PULL UP alarm that would have allowed them to recover significantly from the height and would have stopped the approach.
As the aircraft climbed through 400 ft, the crew retracted the landing gear, announced that they would call back on the "long final" and then selected an altitude of 2,000 ft. The aircraft was then located near the 308° radial of the HAI VOR, indicating the end of the downwind leg defined on the approach chart. The retraction of the landing gear undoubtedly indicates that the crew is abandoning the approach.
The GPWS alarms and the probable difficulty in seeing the runway likely led the crew to consider that the continuation of the approach was compromised in the short term. The crew's radio message indicating that they will call back on "long final" may constitute a "mechanical" readback from the PNF of the controller's last request, delayed due to GPWS alarms.
The adjective "long", not used by the controller, would, however, indicate that the crew, or at least the PNF, is aware that they could turn onto finals now, but that they had not completely abandoned landing according to another strategy that may not yet be well defined or shared with the PF.
The crew responded to the approach gear down alarm by cancelling the corresponding audible alarm and then engaged the LVL/CH mode (with the previously selected altitude of 2,000 ft), which increased engine thrust and changed the vertical mode of the Flight Director. The latter provided instructions to maintain a speed of 160 kt. Autopilot 1 was then engaged. Simultaneously, the crew ordered the flaps to be retracted to 0° and then selected a speed of 180 kt. These actions indicate that the crew wished to accelerate the aircraft and had abandoned the plan to turn to finals.

Aborted approach
The selected altitude was then changed to 0 feet, which was likely a handling error. The crew then retracted the slats to 0°, 14 knots below the usual speed and below the usual acceleration altitude. The crew probably did not perceive the aircraft's gradual descent in this phase of flight, with a thrust lever slowly moving back at 1°/s, nor the audible reduction in engine speed.
The very fast sequence of actions, the difficulty of performing the circle-to-land procedure at night without visual cues and in strong tailwind conditions, and the presence of alarms, probably generated stress and made it very difficult for the crew to understand all the states of the automatic flight system.
Passing below 750 ft with landing gear retracted again activated of the audible GPWS alarm. The crew, who then became aware that the aircraft was at a low height and descending, reacted by disengaging the autopilot and applying a nose-up pitch. In this condition the alpha floor protection activated. Alpha floor is a low speed protection that applies Takeoff/Go Around (TOGA) thrust.
The increase in thrust produced a nose-up effect that required appropriate nose-down action on the controls and trim. The crew did not react while the pitch increased to 27°. The stick shaker then activated to warn the crew of an impending stall. This led the crew to manually select TOGA 3 seconds later. The stall procedure also calls for a decrease in attitude, but the PF did not changed the attitude, probably for fear of descending the aircraft and striking the sea. It is also possible that he may not have been aware that the aircraft's attitude was excessive while his attention was focused on controlling the aircraft in roll. The aircraft remained in a stall situation until it impacted with the sea.

CAUSES:
The accident was caused by inappropriate actions of the crew on the flight controls which brought the aircraft into a stall that could not be recovered. These actions were successive to an unstabilized visual maneuvering, during which many different alarms related to the proximity to the ground, the aircraft configuration and approach to stall sounded. The crew's attention was focused on the management of the path of the aircraft and the location of the runway, and they probably did not have enough mental resources available in this stressful situation, to respond adequately to different alarms.

Contributing to the accident:
- The weather conditions at the airport (wind gusts around 30 kts).
- Lack of training or pre-flight briefing of the crew in accordance with the Yemenia company operations manual, given the reluctance of the pilot to execute the MVI [Visual Manoeuvring with Prescribed track] (none of the documents submitted in the investigation shows this training).
- The non-execution of the MVI maneuver by the crew (the plane left the LOC axis after the published point which is 5.2 NM), implying that the crew delayed the turn to reach the right hand downwind leg.
- The non-application by the crew of the procedure following the PULL UP-alarm.

METAR:

22:00 UTC / 02:00 local time:
FMCH 292300Z 21025G35KT 9999 FEW020 25/16 Q1017 TEMPO 18015G30KT=
wind from 210 degrees at 25 knots, gusting to 35 knots; unlimited visibility; few clouds at 2000 feet; temperature 25°C, dew point 15°C; 1017 mb; temporary winds from 180 degrees at 15 knots, gusting to 30 knots

22:00 UTC / 01:00 local time:
FMCH 292200Z 18022G33KT 9999 FEW020 24/17 Q1018 NOSIG=
[wind from 180 degrees at 22 knots, gusting to 33 knots; unlimited visibility; few clouds at 2000 feet; temperature 24°C, dew point 17°C; 1018 mb

Accident investigation: