What happened
On January 13, 2000, a Shorts SD3-60, registration HB-AAM, was conducting a flight from Tripoli International Airport to Marsa Brega, Libya. The aircraft was carrying 38 passengers and 3 crew members. While on final approach, approximately 4.5 nautical miles from the destination, the left engine experienced a sudden flameout. Shortly thereafter, the right engine also failed.
In the moments following the dual engine failure, the crew attempted to relight the engines and notified operations of their intention to ditch. The aircraft struck the sea surface with a 10-degree nose-up attitude. The impact caused the aircraft to break apart and sink within minutes. The accident resulted in 21 fatalities, including 20 passengers, and several serious injuries to both crew and passengers.
The investigation
The investigation examined the aircraft wreckage, which was recovered from the seabed at a depth of 38 meters. Investigators analyzed the flight recorders (CVR and DFDR), which were recovered from the wreckage. Technical examinations of the two Pratt & Whitney PT6A-67R engines were conducted by specialists, including representatives from the engine manufacturer.
Testing of fuel samples collected from the wreckage confirmed that the fuel met Jet A1 specifications and showed no signs of contamination or water. The investigation also reviewed the crew's cockpit communications and the aircraft's maintenance history. Furthermore, the committee evaluated the crew's use of anti-icing systems and their management of the descent following the initial engine failure.
Findings
- The primary cause of the accident was the sudden flameout of both engines during the approach phase.
- Mechanical inspections of both engines revealed no evidence of internal mechanical failure, metal fatigue, or metal-to-metal failure.
- There was no evidence of fuel mismanagement, as the fuel levels were consistent with the flight plan and the fuel was found to be clean.
- The crew was distracted by discussions regarding aircraft systems and type ratings, which likely led to them failing to notice ice formation on the windshield and an increase in airspeed during descent.
- The crew failed to activate the engine anti-icing system, focusing instead on pitot-static and windshield anti-icing.
- The investigation noted that the crew did not utilize the engine anti-icing system, and the aircraft was flying in conditions where ice accumulation was a factor.
Safety action
- The investigation noted that while the aircraft was not equipped with life jackets, the safety instruction cards and seat backs indicated the use of seat cushions as flotation devices. However, the committee found that the responsibility lies with the operator to ensure safety instructions are precise and that passengers are properly briefed on emergency equipment usage.