Cracked engine casing likely cause of Skyvan crash
-UK inspector
Stabroek News
November 16, 2003
A cracked engine casing is being seen as the likely cause of the Trans Guyana Skyvan crash last Saturday, which killed two persons.
Following this preliminary discovery the Guyana Civil Aviation Authority (GCAA) is to issue a special inspection bulletin to the Guyana Defence Force for it to inspect the engines of the two Skyvans it now operates.
Senior Inspector with the UK Aviation Accident Investigation Board Alan Simmons, in the country to investigate the crash, said yesterday that there had been a crack in the casing of the engine which allowed the compressor pressure to fail.
"That was the reason why the engine ran down," he said.
Detailed technical work is yet to be done, but Simmons said the investigators were working on the assumption that it would be confirmed and were taking the precaution of issuing the inspection bulletin in case there were any other aircraft engines which had the problem.
He said the bulletin inspection was just a preventative measure based on the information now available. He cautioned that the information might change as the examination of the engine was still in an early stage, and special equipment was needed to investigate the problem in detail.
In the meantime, Simmons said the team was in discussions with the Federal Aviation Administration (FAA) as the problem may apply to other aircraft in other countries as well. GCAA Director General Chabeenanan Ramphal noted that the first transcript of the Skyvan's cockpit voice recorder should be sent back to Guyana by Thursday. A sample of fuel was sent to the US National Transportation Safety Board (NTSB). The propellers and the engines have been prepared for shipping to the manufacturers of the aircraft in the UK. The investigations will be carried out in the UK under the supervision of the NTSB.
Recalling what may have occurred on the day of the crash, Simmons said that the aircraft took off at maximum operating speed and carried out a category safe performance take-off. During take-off one of the flaps was retracted to 18 degrees, the right engine failed and the crew was unable to maintain height. He was not entirely sure why they were unable to maintain height. He said the investigators believed, "it might have been due to the crew attempting to avoid any injuries on the ground."
The aircraft, he said, descended in an area which "was not friendly" on rough undulating ground, so that when it touched the ground it was broken up by the bumps and furrows. The investigators believed that it reached a height of 200 to 300 ft. It had no flight recorder, which was not a requirement.
AAIB Inspector (Operations) Keith Conradi said that the pilot turned the Skyvan at a 90-degree angle. He believes that the pilot was "trying to ensure no injuries on the ground... He was trying to avoid trees and houses."
Simmons believed, too, that the pilot and surviving crew were lucky to survive "because the impact was very severe... it was a partial survival in my estimation. The severity of the impact itself was potentially fatal without being hit by bits of wreckage."
Head of the investigating team Clifton Bedaysie said investigators had weighed each part of the cargo and plane load and it was "within the limit. We don't have any doubts." Maximum weight is 13,500 with fuel, passenger and cargo, and it was some 200 pounds less than the maximum.
In response to a question about evidence being tampered with by persons on the scene before the investigators arrived, Simmons said it was possible, but that it was hard to interfere with the wreckage sufficiently to lose the evidence.
All of the wreckage has been removed, but Ramphal said that the GCAA had asked the owner to keep it in an enclosed space for further investigations if necessary. (Miranda La Rose)