Mint Explainer | How Air India blundered by missing a routine airworthiness review for an aircraft

The regulator did not name the aircraft type but referenced the registration code of an Airbus A320 (VT TQN), implying that it was a single-aisle (narrow body) jet. Air India, admitting the lapse, ordered an internal inquiry into the matter and suspended eight staffers.

Mint breaks down the process of getting airworthiness certificates, how the slip-up may have happened, and what’s next for the airline as the regulator investigates the matter.

What are airworthiness certificates?

Airworthiness certificates validate the safety of aircraft for commercial operations. There are two types of airworthiness certificates. One is the Certificate of Airworthiness (C of A) issued by the Directorate General of Civil Aviation (DGCA) and the other is the Airworthiness Review Certificate (ARC), which is the mandatory annual renewal document issued or approved by the DGCA.

The C of A confirms that an aircraft was manufactured and modified according to the engineering and safety specifications set by the manufacturer and that it has been physically inspected and is deemed safe for flight at the time of issue. The C of A is issued when a new or imported aircraft is registered for the first time in India.

The ARC ensures continuing airworthiness of an aircraft. It is issued after a comprehensive annual review of its maintenance history and records and has cleared a physical inspection to verify compliance with all airworthiness standards.

The ARC is issued by the DGCA's Airworthiness Directorate. Alternatively, the DGCA authorizes an airline's approved maintenance organization to review and inspect aircraft. Both airworthiness certificates must be valid for an aircraft to operate commercially. Operating an aircraft without a valid airworthiness certificate is a serious legal and safety violation.

The process is similar to the one followed by the US Federal Aviation Administration. The DGCA charges a fee for issuing such certificates.

How big was the lapse by Air India?

The Air India aircraft with an expired airworthiness certificate operated on November 24 and 25.

Aviation expert Mark D Martin, the chief executive officer of Martin Consulting, said this was the first instance of an airline flying an aircraft without the mandatory certificate in India's civil aviation history. It was a gross violation that may have risked the lives of a few hundred people.

The lapse came after the crash of AI-171, which killed 241 people shortly after taking off from Ahmedabad airport on 12 June.

How are airworthiness certificates issued to Air India?

The DGCA has delegated authority to Air India to issue ARCs in respect of the aircraft it operates. These certificates are issued annually for an aircraft after a comprehensive review of its maintenance records, physical condition and verification of compliance with all airworthiness standards. It acts as an annual validation of the aircraft's main C of A.

Air India’s engineering department reviews the aircraft and prepares a report which is sent to the DGCA for approval. Not all aircraft are physically inspected by the regulator. Captain Shakti Lumba, an independent aviation and aerospace professional, said physical inspection is not done because the aircraft are located at different places at any given time. Besides, the regulator is short-staffed.

How did Air India miss the certification process?

There are different theories for Air India missing the annual review of this aircraft. Typically, airlines across the world and in India have a software that alerts them to certification requirements such as ARC and pilot licence renewals. In this case, the alert was possibly missed or overlooked, people aware of the procedure said.

Air India is yet to respond to Mint about the software used and their alert system in such cases.

Another theory is that this was a “clerical error", which experts including Martin have rubbished, calling it a “possible deliberate oversight".

However, according to the DGCA, after the merger of Vistara into Air India in 2024, it was decided that ARCs of all 70 Vistara aircraft would be done. Certificates for 69 aircraft were issued by the DGCA after satisfactory compliance by Air India.

The 70th aircraft was grounded for a month for an engine change, during which the plane’s ARC expired. The aircraft was released for service after the engine change.

Air India informed the regulator about flying the aircraft on the expired certification on 26 November.

So, who was responsible for the lapse?

This aircraft was deployed on eight flights over two days, according to the DGCA. This means its airworthiness status was overlooked between takeoff and landing, when some maintenance and checks are carried out.

Lumba pointed out that it is primarily the responsibility of the engineering department of the airline to ensure airworthiness revalidation. This lapse, he said, could be because the software did not provide updates.

He also pointed out that there are placards of the certificates and their validity in the cockpits, which pilots need to check. Both the departure engineer and the pilot-in-command are responsible for ensuring that the aircraft's certificates are valid before the flight takes off. Martin said pilots generally do not check airworthiness certificates, but departure engineers are supposed to.

A former DGCA official said that airlines often skim through certain pre-flight checks in order to improve on their on-time performances. Also, there may not always be enough time between landing and subsequent take-off to carry out all maintenance checks.

How many flights did the aircraft make without airworthiness certificates?

According to flight tracking site FlightAware, the aircraft bearing registration number VT-TQN made six flights on 25 November before it was grounded the next day. The first flight departed from Mumbai at about 7.30 am to Delhi. The last flight of the day was from Hyderabad to Mumbai, which was completed at about 12.45 am on 26 November.

On 24 November, when the ARC expired, the aircraft made two flights, going by the regulator’s version of events.

What next for Air India?

Pending an inquiry, the DGCA is likely to impose a financial penalty of ₹1-2 crore on Air India. The airline may terminate some of the staffers involved. The aircraft will be grounded until a fresh ARC is issued.