Assessment shows that only outer covering of undercarriage was torn, inner structure of fuselage was intact, says airline official.

The Air India Express plane that flew for four hours despite a tear in its belly after hitting a boundary wall at Tiruchi airport could have completed its journey to Dubai safely and was only diverted to Mumbai as repairs would be easier at a home base, airline sources said.

Various teams, including those of the Aircraft Accident Investigation Bureau (AAIB), Directorate General of Civil Aviation (DGCA) and the airline were in Mumbai as part of an inquiry into the incident. The two pilots have been suspended pending investigation.

An airline official, who spoke on condition of anonymity, said the assessment of damage to the aircraft showed that only the “outer covering of the undercarriage or fibreglass panel was torn but the inner structure of the fuselage was intact.”

There was no damage to the pressurisation system that ensures oxygen supply within the airplane and all the cockpit parameters were normal, the official said.

He added that at the time the plane hit the boundary wall, at 1.19 a.m. on Friday, neither the crew nor the passengers felt any impact and that the plane flew and landed safely in Mumbai at 5.35 am.

While the Tiruchi Air Traffic Control informed the pilots about the mishap within a minute, the cockpit crew decided to continue flying because there were no warning signals. However, in another 15 minutes airport and airline officials reached the site and discovered that besides the wall, the antenna of the airport’s instrument landing system (ILS) and the wire mesh had been damaged and that there was also aircraft debris lying around. Subsequently, repeated communications were sent by Mumbai ATC to the pilots of IX 611.

“The role of the ATC is to only advise the pilot in the event of such an incident,” said Rajeev Saxena, General Manager of ATC in Mumbai. “Once airborne, the aircraft is under the pilot’s control and is his responsibility.”

A pilot, who did not wish to be identified, said that the airline took almost three hours to direct the cockpit crew to divert because it possibly took that much time to conclude that it was indeed flight IX 611 that had hit the boundary wall.

Air India Express CEO Shyam Sundar had also earlier said that the decision to divert the plane was taken as soon as the extent of damage was known. He added that the plane was diverted to Mumbai because it was the closest airport and being a major airport it was the best option to arrange an alternate plane for passengers as well as to carry out repairs on the damaged aircraft.

‘No safety issue’

Independent aviation consultant Shakti Lumba backed the airline’s stand and said, “the plane flew for nearly four hours, which means there was no safety issue. Moreover, the damage is to the outer shell and not to the pressurisation tubes.”

Probe lack of height

Investigators will have to determine why the plane was flying at such a low height that it hit the airport’s perimeter wall.

Mr. Lumba lists different possibilities on why the plane took longer to gain height.

First, the aircraft may have been overloaded and the power and speed usedwere not sufficient. Secondly, the pilot may have selected a wrong flap setting thus not getting the required lift. The third scenario is where a pilot selected ‘flex power’ instead of using full power, resulting in the plane getting airborne slowly.

The actual cause will only be known after examining the flight data recorder.

(With inputs from Aditya Anand in Mumbai)