IndiGo tail strike: plane arrives in Delhi with damaged belly, cleared for flight to Bengaluru

More than 10 days on, neither DGCA nor IndiGo say when the tail strike occurred; multiple airline sources, including pilots, say that the mandatory walkaround inspection had been skipped because it rained at the airport

An IndiGo Airbus A321 aircraft parked in Bengaluru since September 9, which is the subject of a DGCA enquiry for scraping against the runway surface, may have arrived in the same condition at its previous stop at Delhi airport. Airline sources familiar with the incident said the massive abrasions extending from the wings of the plane to the tail went completely unnoticed and the aircraft was cleared for the next flight to Bengaluru.

On September 17, after a purported photo of the damaged aircraft went viral on social media, a senior Directorate-General of Civil Aviation (DGCA) official said that the regulatory body was investigating the IndiGo tail strike and the two pilots and cabin crew on 6E-6054 that flew from Delhi to Bengaluru on September 9 were off-rostered pending an enquiry. The official said the digital flight data recorder (DFDR) had been sent to aircraft manufacturer Airbus for a technical analysis, which was awaited. The Hindu couldn’t independently verify the authenticity of the photo.

However, the latest information from multiple sources at IndiGo suggests that the aircraft registered as VT-IBI also arrived at Delhi airport on September 9 with a damaged fuselage, which went unnoticed and the aircraft was cleared for the next flight to Bengaluru.

According to messages exchanged on a WhatsApp group of IndiGo staffers and reviewed by The Hindu, the airline suspended an aircraft maintenance engineer (AME) of the airline tasked with inspecting engines and airframes at Delhi airport because he failed to conduct the mandatory walkaround, or an external inspection of the aircraft carried out before every departure, and issued a “certificate of release to service” for it.

Multiple airline sources, including pilots, said that the mandatory walkaround inspection was skipped because it was raining at the airport.

They also said that since the aircraft was flown to Bengaluru despite the massive abrasions through a large section of the underbelly, the cockpit crew may have also failed to conduct the mandatory pre-flight walkaround.

A walkaround inspection of the exterior of a plane is carried out both by the AME team and pilots before every take-off to check the aircraft structure for damage from impact, or to check for signs of fuel, oil or hydraulic leaks. 

More than 10 days since the incident, neither IndiGo nor the DGCA has disclosed where the tail strike occurred and how many flights the damaged aircraft operated before being grounded at Bengaluru after 6E-6054 landed at 6.15 p.m. on September 9. The Hindu sent a detailed questionnaire to IndiGo CEO Pieter Elbers who replied, “The matter is under review by DGCA. Hence we can’t go into any details.”

In a statement earlier this week, the airline said, “On 9th September 2024, an IndiGo A321 was grounded in Bangalore due to a tail strike.”

The Hindu has also e-mailed a detailed questionnaire to Secretary, Ministry of Civil Aviation, Vumlunmang Vualnam, and asked whether the DFDR data had revealed when the tail strike occurred, and if the enquiry will be expanded to include the crew on the previous flight as there may have been changes in crew as well as the AME team in Delhi. However, there was no response till the time of going to press. The Director-General of the DGCA is on leave and couldn’t answer queries sent to him via text message.

The flight 6E-6054 departed for Bengaluru at 3.50 p.m. on the day of the incident and arrived at Bengaluru at 6.15 p.m. and has been grounded there ever since, according to data from flight tracking website ‘flightradar 24’. Earlier in the day, the aircraft conducted two more flights, Bengaluru-Delhi (6E-869) and Delhi-Bengaluru (6E-2109). It had a night halt in Delhi the previous day after flying in from Mumbai, which is when aircraft typically undergo daily maintenance checks.

An airline engineer said that the pilots of the previous flight also erred in not informing the AME staff of a suspected tail-strike or hard landing.

It is after such an input from the pilots that the engineering team extensively checks the aircraft structure for defects to ensure it is serviceable for the next flight. If there are any faults, the AME team either mentions them in the minimum equipment list (MEL) and declares the aircraft airworthy, or grounds it for repair works.

A tail strike occurs when the rear section of the aircraft belly comes in contact with the runway during either takeoff or landing. The kind of damage sustained in this incident, extending from the wings of the aircraft almost till the tail, could possibly result in de-pressurisation in the passenger cabin making breathing more difficult. Since the air pressure inside the cabin is maintained at the same level experienced at 8,000 feet, a breach can result in decompression as the low pressure maintained inside the cabin will result in air rushing outside where the pressure is high. A physical damage to the fuselage can even damage the tail cone impacting aerodynamic functions as well as the sensitive equipment inside the aircraft such as hydraulics and flight controls.

The Airbus checklist advises pilots that in the event of a tail-strike, the aircraft must land as soon as possible. It also says that after such an event, the aircraft must not exceed 10,000 feet in altitude in order to minimise pressure changes and ensure passenger and crew comfort.

Airbus pilots say that the A321 aircraft are more prone to tail strikes because of their extended length as compared to an Airbus A319 and A320. The A321 is 6.94 metres longer than the A320 and requires a more delicate angle of inclination at the time of landing and take-off. 

Last year too, the DGCA slapped a penalty of ₹20 lakh on IndiGo after at least four incidents of tail strikes came to light in a span of six months, and the regulator found “systemic deficiencies in operations, training and engineering procedures,” following an inquiry.

Published - September 20, 2024 08:42 pm IST