Factual Information
The aircraft involved was a Piper PA-31-1T1040, serial number T-8375002, registered as 5Y-UAC. It was powered by two Pratt & Whitney PT6A-11 engines. The aircraft was manufactured by Piper Aircraft Corporation, Canada, in 1983.
History of the Flight
The flight departed Wilson Airport at approximately 0350 UTC carrying one pilot, one passenger, and a load of 'Miraa'. The pilot's load sheet indicated the aircraft was correctly loaded. Immediately after takeoff, the pilot reported to Air Traffic Control (ATC) that he was experiencing a technical problem. He proceeded to attempt a landing at Jomo Kenyatta International Airport (JKIA). The aircraft then impacted the ground and burst into flames. The pilot and passenger suffered fatal burns and injuries. The point of impact was approximately 3.5 kilometres from the extended centreline of Runway 06 in Nairobi National Park.
Injuries to Persons
The pilot and passenger sustained fatal injuries.
Damage to Aircraft
The aircraft was burned and destroyed. The port engine was partially attached to the wing but its propeller was detached. The starboard engine and propeller were detached from the wing; the starboard propeller appeared to have been feathered. The area around the wreckage was extensively burned.
Other Damage
Apart from grass, shrubs, and trees being burned and damaged, there was no other damage to property or persons.
Personnel Information
Captain Benjamin Njoroge Murimi, a Kenyan born on 24 December 1957, held a Kenyan Commercial Pilot's Licence (No. YK-1648-CL) issued on 29 January 1988 and last valid to 20 September 1995. He was rated for the Piper PA31-1T1040 among other types. His Instrument Rating was valid until 22 February 1996. As of 7 September 1994, he had a total flying experience of 7,145 hours.
Aircraft Information
The aircraft had a Kenyan Certificate of Airworthiness (No. 1663) in the Public Transport Category, issued on 30 August 1994 and valid until 29 August 1995. It was registered to United Airlines Limited of Nairobi. Maintenance was carried out in accordance with approved schedule; a Check III inspection was certified on 20 August 1994. Total airframe hours since new were 4,259 as of 23 January 1994.
Meteorological Information
Weather was relatively calm winds, few clouds, and good visibility. It was not considered a factor in the accident.
Aids to Navigation
Not applicable; no evidence of navigation equipment malfunction.
Communications
The pilot radioed Wilson Control Tower and indicated a 'technical' problem immediately after takeoff. ATC instructed him to proceed to JKIA.
Aerodrome Information
Wilson Airport has two bitumen runways; Runway 07/25 is 1,463 x 24 metres. The aircraft took off from Runway 07.
Flight Data Recorder
Not required and not fitted.
Wreckage and Impact Information
The accident site was flat with tall grass, bushes, and short acacia trees. One propeller was found approximately 4.94 metres from the impact point, the second propeller about 41 metres, and the main fuselage, wings, and engines about 60.6 metres from the impact point. The area from the impact point to the main fuselage was extensively burnt, with bags of 'Miraa' scattered.
Medical and Pathological Information
The pilot and passenger were extensively burnt and suffered fatal injuries to body tissue and bones.
Fire
The aircraft burst into flames on impact, extensively burning the surrounding area.
Survival Aspects
The impact and accident were not survivable.
Test and Research
The starboard engine, which appeared to have minimal power on impact, was removed for strip inspection. Observations included: the beta block (carbon block) on the propeller reversing lever was missing; the clevis pin attaching the reversing lever to the beta valve was badly worn; the low pitch stop switch plunger had a worn groove; and one wire on the switch was loose. The engine showed evidence of still running on impact, with compressor blades having severe rub.
Additional Information
Prior to takeoff, the pilot had indicated to an attendant that the starboard beta light was coming on and off without reverse thrust being selected. The previous day, the aircraft had been checked for a beta light problem and a switch malfunction was found. The port engine had also been checked for low fuel pressure and ground run satisfactorily.
Analysis
The aircraft departed Wilson Airport for Mogadishu at approximately 0350. A technical problem occurred immediately after takeoff. The pilot attempted to land at JKIA, then turned right and impacted terrain. The starboard engine appeared to have very low power but was still running; the starboard propeller appeared feathered.
Conclusion
- The pilot was properly licensed and experienced.
- The aircraft had a current Certificate of Airworthiness.
- The technical problem was probably due to a starboard engine/propeller malfunction.
- The aircraft turned right while trying to land.
Cause
The probable cause of the accident was the starboard engine and propeller malfunction, resulting in the aircraft colliding with the ground.
Contributing Factor
Contributing to the accident was the aircraft turning right into the malfunction engine. Also contributing was the aircraft descending rapidly for some reason immediately after the technical problem.
Safety Recommendations
Companies receiving engines and propellers after overhaul should check to ensure they are overhauled to approved specifications.