KUALA LUMPUR: Possible structural failure could have been the cause of the crashed Gabriel BK-160TR aircraft in Kapar, Klang.
Universiti Kuala Lumpur's Malaysian Institute of Aviation Technology head of aviation search and rescue department, Associate Professor Major Dr Mohd Harridon Mohamed Suffian, said based upon eyewitness accounts, the wing had disintegrated from the fuselage of the aircraft.
"This then led to sudden decrease of altitude and the aircraft subsequently nose-dived."
He said the wing disintegration had raised question on the structural integrity of the aircraft, as it has the ingrained capability to withstand high values of G-forces within the range of positive 4G and negative 2G.
"Within this capacity, the aircraft could perform manoeuvres of high loads such as acrobatic turns and dives.
"Thus, the structural integrity of the aircraft is high which poses the question as to why there was disintegration of the aircraft during mid-flight."
As such, Harridon said it was important for the investigation to be focused on the aircraft's structure, including its maintenance procedures.
"It's imperative that the technical documentation of the aircraft is perused and scoured to identify whether repairs were actuated or not upon the wings or the structure of the aircraft and if repairs were made.
"It should be discerned whether the repairs conform to the prescribed standards or protocols of the Original Equipment Manufacturer (OEM).
"The maintenance logs of the aircraft should also be observed as well to detect any anomalies with regards to the maintenance practices that were performed on the aircraft."
Harridon added that the debris of the aircraft should also be analysed comprehensively to detect any charring patterns that are consistent with abnormal combustion of the engine or the existence of a mini explosion.
"It's also vital to investigate whether there was a fuel line leak since there was another eyewitness account that stipulated there was a mini explosion or spark and leakages of fuel lines would exacerbate the situation," he said.
He added that since the aircraft was not installed with a black box, other means of recording could be utilised to aid the investigation.
"Investigators could utilise FlightRadar24 as it shows the altitude, heading and manoeuvres of the aircraft which can be helpful to the investigation process."
Malaysian Pilots Association president Captain Abdul Manan Mansor said it took a significant amount of G-force to disentangle the wings off the fuselage of the aircraft, according to what was seen in eyewitness videos.
This, he said, could mean that the aircraft, which was certified to fly aerobatic manoeuvres, was subjected to a higher amount of G-force than it is capable of.
"The Italian manufacturer needs to answer this query in more detail as the maximum G the aircraft could take is 4.4 G.
"If the aircraft was flown higher than 4.4 G, this could disintegrate the composite wing."
Meanwhile, Civil Aviation Authority of Malaysia chief executive officer Datuk Captain Norazman Mahmud, when asked whether the aircraft had made any "unusual altitude recovery training" requests on the day it crashed, said it had only filed for a recreational flight.
On Feb 13, Gabriel BK-160TR bearing the registration I-POOC crashed in Kampung Tok Muda, Kapar, Klang.
The crash killed two onboard, namely, Daniel Yee Hsiang Khoon, 30, and Roshaan Singh Rania, 42.
Operated by Air Adventure Flying Club, it departed from Sultan Abdul Aziz Shah Airport, Subang, Selangor at 1.28pm for a recreational flight.