Mid-air ‘hijack’ alert activates security protocol in Mumbai-bound Air India flight

Although the pilot told ATC it was a false alarm, there was no let up in the protocol. The flight reached Mumbai, where the authorities were ready.

At 8.40pm on Monday night, Air India’s Mumbai-bound flight AI 2957 which had just taken off from New Delhi’s Indira Gandhi airport sent an emergency signal to air traffic control (ATC) in the Capital, suggesting it had been hijacked.

The aircraft was taken to an isolation bay. (File photo)

Delhi ATC immediately set in motion a protocol that requires alerting the destination airport, security agencies, the Indian Air Force. A central committee, comprising representatives from Delhi police, Central Industrial Security Force (CISF), which is responsible for airport security, Airports Authority of India (AAI), Bureau of Civil Aviation Security (BCAS) and the Air Force was formed.

Although the pilot informed ATC that it was a false alarm, there was no let up in the protocol. “How can the ATC assume that the pilot is not being pressured to tell the authorities that the flight is uneventful? What if he is at gunpoint and has been asked to say so?” asked a former ATC official who asked not to be named.

The flight, with 126 passengers, landed in Mumbai at 9:47pm, where the authorities were ready for it. “An aerodrome committee at Mumbai airport was formed as per protocol and a full emergency was declared at the airport, at around 9:30pm, where all the local police and stakeholders along with NSG (National Security Guard) were deployed,” a Mumbai airport official said, asking not to be named.

The aircraft was taken to an isolation bay, and passengers were allowed to deboard only after an hour, after establishing that all was in order, the official added.

According to a Delhi airport official who asked not to be named, the drama started when “the aircraft’s transponder sent a ‘squawk 7500’ code to the Delhi ATC immediately after its take off.” The signal was up for three minutes, they added.

Squawk codes are four-digit codes ranging from 0000 to 7777 set on an aircraft’s transponder. These unique identifiers allow air traffic control units to distinguish between different aircraft.

However, in ATC parlance, 7500, 7600 and 7700 are fixed codes for emergency situations. While squawk 7600 and 7700 indicate radio communication failure and any aircraft-related emergency respectively, squawk 7500 indicates unlawful interference — in other words, a hijack.

Aviation ministry officials said that the airline had reported the matter and the Directorate General of Civil Aviation (DGCA), along with along with BCAS and CISF, has begun its probe into the incident. “The aim is to find out the cause of the false indication. Whether it was the pilot error or the air traffic controller on duty who, may be, misread the indication will only be clear after the investigation is concluded,” one ministry official said on condition of anonymity.

HT reached out to DGCA officials but did not get a comment till the time of going to print.

An Air India spokesperson remained unavailable for a comment. However, an airline official familiar with the incident said, “There has been no indication of any crew involvement into the incident. It could have been a technical error, all of which will be known only after the regulator’s (the DGCA) enquiry is concluded.”

A second ministry official added: “The pilot, however, learnt about the false indication after take off. He informed the local ATC that the aircraft was operating in a regular situation and that it was not hijacked.”

“However, once the indication is made, the stakeholders need to follow a protocol and prepare for the worst,” this official added on condition of anonymity.

After landing, “the pilot repeatedly insisted that the plane had not been hijacked and that it had been a regular flight,” the Mumbai airport official said.