Accident Boeing 737-8AS (WL) ET-ANB,

ASN Wikibase Occurrence # 321367

Date:	Monday 25 January 2010
Time:	02:41
Type:	Boeing 737-8AS (WL)
Owner/operator:	Ethiopian Airlines
Registration:	ET-ANB
MSN:	29935/1061
Year of manufacture:	2002
Total airframe hrs:	26459 hours
Cycles:	17823 flights
Engine model:	CFMI CFM56-7B27
Fatalities:	Fatalities: 90 / Occupants: 90
Aircraft damage:	Destroyed, written off
Category:	Accident
Location:	11 km SW off Beirut International Airport (BEY) - Lebanon
Phase:	Initial climb
Nature:	Passenger - Scheduled
Departure airport:	Beirut International Airport (BEY/OLBA)
Destination airport:	Addis Ababa-Bole Airport (ADD/HAAB)
Investigating agency:	MoPW&T
Confidence Rating:	Accident investigation report completed and information captured

Narrative:
A Boeing 737-8AS(WL) passenger jet, registered ET-ANB, was destroyed in an accident 6 km southwest off Beirut International Airport (BEY), Lebanon. All 82 passengers and eight crew members were killed. The airplane operated on Ethiopian Airlines flight ET409 from Beirut International Airport (BEY) to Addis Ababa-Bole Airport (ADD).
Instruments meteorological conditions prevailed for the flight, and the flight was on an instrument flight plan. It was night in dark lighting conditions with reported isolated cumulonimbus clouds and thunderstorms in the area.
Flight ET409 was initially cleared by ATC on a LATEB 1 D Standard Instrument Departure (SID) from runway 21. Just before takeoff, ATC changed the clearance to an "immediate right turn direct Chekka".
The Boeing 737 took off from runway 21 at 02:36. After takeoff ATC instructed ET409 to turn right on a heading of 315° and change frequencies and contact Beirut Control. ET409 acknowledged the clearance and continued a right turn. ATC instructed ET409 to turn left heading 270°, which was acknowledged. The flight continued the climbing left turn to heading 270° but did not maintain that heading. The aircraft continued on a southerly track. Just prior to reaching altitude of 7700 feet, the stick shaker activated, sounding for a period of 29 seconds. Meanwhile the airplane reached an angle of attack (AOA) of 32° and began a descent to 6000 feet. When the stick shaker ceased, the aircraft began to climb again. At 02:40:56, just prior to reaching 9000 feet, the stick shaker activated again, sounding for a period of 26 seconds.

After reaching 9000 feet the aircraft made a sharp left turn and descended rapidly. The maximum registered bank angle was 118° left and the airplane reached a maximum registered speed was 407.5 knots at a G load of 4.412. The airplane disappeared from the radar screen and crashed into the Mediterranean Sea at 02:41:30.

PROBABLE CAUSES:
1- The flight crew's mismanagement of the aircraft's speed, altitude, headings and attitude through inconsistent flight control inputs resulting in a loss of control.
2- The flight crew failure to abide by CRM principles of mutual support and calling deviations hindered any timely intervention and correction.
CONTRIBUTING FACTORS:
1- The manipulation of the flight controls by the flight crew in an ineffective manner resulted in the aircraft undesired behavior and increased the level of stress of the pilots.
2- The aircraft being out of trim for most of the flight directly increased the workload on the pilot and made his control of the aircraft more demanding.
3- The prevailing weather conditions at night most probably resulted in spatial disorientation to the flight crew and lead to loss of situational awareness.
4- The relative inexperience of the Flight Crew on type combined with their unfamiliarity with the airport contributed, most likely, to increase the Flight Crew workload and stress.
5- The consecutive flying (188 hours in 51 days) on a new type with the absolute minimum rest could have likely resulted in a chronic fatigue affecting the captain's performance.
6- The heavy meal discussed by the crew prior to take-off has affected their quality of sleep prior to that flight.
7- The aircraft 11 bank angle aural warnings, 2 stalls and final spiral dive contributed in the increase of the crew workload and stress level.
8- Symptoms similar to those of a subtle incapacitation have been identified and could have resulted from and/or explain most of the causes mentioned above. However, there is no factual evidence to confirm without any doubt such a cause.
9- The F/O reluctance to intervene did not help in confirming a case of captain's subtle incapacitation and/or to take over control of the aircraft as stipulated in the operator's SOP.

METAR:

00:00 UTC / 02:00 local time:
OLBA 250000Z 31008KT 280V340 8000 VCTS FEW020CB SCT026 13/06 Q1014 NOSIG=
wind 310 degrees at 8 knots, variable from 280° to 340°; visibility 8km; thunderstorms in the vicinity; few clouds with cumulonimbus at 2,000 ft; scattered clouds at 2,600 ft; temperature 13 degrees C, dew point 6 degrees C, pressure 1014 hPa

01:00 UTC / 03:00 local time:
OLBA 250100Z VRB03KT 4000 SHRA FEW020CB BKN026 12/07 Q1014 NOSIG=

Accident investigation: