AIX flight ran into unpaved ground before taking off
Mumbai: The Air India Express Boeing 737-800 that flew with a ripped underbelly for close to four hours on Friday, had overrun the end of the Trichy airport runway into the unpaved ground before lifting off to amore eventful takeoff.
The Dubai-bound aircraft with 136 people on board, which departed at1.18am, hit a localizer antenna and scooped out a portion of the airport perimeter wall on takeoff. With a long, gaping wound running along its underbelly, the Boeing 737 climbed to 36,000 feet and flew a distance of around 1,500km and reached Muscat airspace before being diverted to land in Mumbai at 5.30am.
An Airports Authority of India (AAI) source said, “The skid marks on the ground extend way beyond the runwayend. The aircraft damaged a runway end-light too.”
Capt Mohan Ranganathan, air safety expert, said, “It looks like the pilots tried to reject takeoff. It appears to be a case of indecision. They seem to have continued without realizing that they’d used up a lot of runway in the indecision.”
He recalled the Indian Airlines Aurangabad April 1993 flight IC491crash. The Boeing 737 didn’t lift off till almost at the end of the runway. “It then hit a truck on a highway plying on a road near the end of the runway. One of my close friends, Capt Sanjeev Mu-
Research found problem is independent of operating airline, aircraft type, equipment and method used lherkar, and his entire family died in that crash. A similar accident could have taken place in Trichy. There’s a road just beyond the perimeter wall,” said Capt Ranganathan.
The Air India Express Trichy overrun is also similar in some aspects to that of Emirates at Melbourne airport in 2009. Dubai-bound Emirates flight 407, operating with an A340-500 aircraft, had taken
Half the crew experienced errors in parameters or configuration at takeoff, some of which involved weight input into flight mgmt system Pilots’ knowledge of these parameter values was most frequently cited strategy used to avoid major errors off from Melbourne on the night of March 20. The aircraft overran the runway during the take off roll, suffered a tail strike on liftoff and then went on to hit structures in its path. Unlike Air India Express pilots, the Emirates pilots return to land in Melbourne.
Investigation by the Australian Transport Safety Board (ATSB) found that the accident resulted from the use of erroneous takeoff performance parameters.
Depending on factors like the weight of the aircraft, length of the runway available and outside temperature, the crew calculates the thrust and takeoff speeds. For instance, the speed at or after which the takeoff should not be aborted, the speed at which the aircraft can lift off safely, the speed at which the aircraft can climb out safely even if it suffers an engine failure and so on.
The ATSB found that the pilots had taken into account incorrect aircraft weight when doing the calculations during the pre-departure preparation. “Due to a number of factors, the incorrect data entry passed through the subsequent checks without detection,’’ the report said.
Following the accident, ATSB undertook a research study that documented 31accidents and incidents identified between January 1989 and June 2009 where the calculation and entry of erroneous takeoff performance parameters, such as aircraft weights and speeds, were involved. It found that “crew actions involving the wrong figure being used, data entered incorrectly, data not being updated, and data being excluded’’ as the cause behind 39% of cases. “This was followed by absent or inadequate risk controls (31%), mostly centred on poor procedures, non-optimally designed aircraft automation systems...,’’ the report stated.
(Above) AIX aircraft skid marks beyond Trichy airport runway indicate overrun on Friday. (L) Mesh from airport perimeter wall found stuck to aircraft undercarriage