On the morning of August 30, Lahore air traffic controllers were surprised to find that an "Indian military plane" had entered Pakistan airspace. They were also confused because, according to the flight plan and pilot identification, it was a Boeing 737 civil aircraft, but was transmitting the code of a military aircraft. They asked the pilot to hold the aircraft and alerted the Pakistani Air Force, which sent two F-16 fighters to escort it for about half an hour until it exited the country's airspace.
In the end, it was actually a SpiceJet flight with 120 passengers on board from Delhi to Kabul. The reason for the mistaken identity was an administrative error by an Indian aviation regulator employee who assigned a military code when registering the SpiceJet aircraft. The unprecedented situation, just a month after Pakistan reopened its tension in post-Balakot airspace, prompted the Prime Minister's Office to intervene. Soon after, an employee of the Directorate General of Civil Aviation (DGCA) was suspended.
In a warm gesture, civil aviation secretary Pradeep Singh Kharola thanked his Pakistani counterpart Sharukh Nusrat for calmly handling the situation. That done, the incident forced the DGCA to speed up its work on digitizing aircraft records. The regulator recently selected Tata Consultancy Services (TCS) for the process.
Development-aware sources said SpiceJet contacted the DGCA in early August to register the aircraft, which was prior to Jet Airways. According to International Civil Aviation Organization (ICAO) standards, when registering an aircraft, aviation regulators worldwide assign a unique 24-digit code called Mode-S – a digitized identification number. The alphanumeric code is relayed by a transponder that can be identified by the advanced radar surveillance system in order to improve the air navigation system and prevent airspace incursions.
The DGCA, however, creates a set of these codes and assigns a certain number to each airline. When airlines seek DGCA to register a new aircraft, the regulator checks its air value and assigns a code. Sources said that in this manual process, the DGCA official mistakenly assigned the SpiceJet aircraft an Antonov AN-32 code – an aircraft used by the Indian Air Force.
“In those days, the work was hectic. SpiceJet was adding at least two to three aircraft daily to its fleet. The mistake came up and no one noticed, ”said a government official. Following the closure of Jet Airways, SpiceJet added 22 Jet aircraft in two months.
The aircraft operated under the military code for almost 20 days and also operated to international destinations such as Colombo and Bangkok. But no one took note until they entered Pakistani airspace.
“Incorrect or missing Mode-S code, caused by equipment malfunction or human input error, may prevent aircraft from displaying on the air traffic controller surveillance monitors and result in potentially hazardous situations,” according to European Union Aviation Safety Agency says.
A senior official from India's air navigation authorities defended supervision, saying air traffic controllers typically work on primary and secondary radar systems, which provide height, speed and altitude details, among others.
“Only when intensified surveillance exists, is the secondary surveillance radar system used to track S-Mode code. Pakistani airspace should use it for Indian aircraft due to the current situation, ”the official said.
Sources said Lahore's air traffic control acted in a mature manner and asked the pilot to hold the aircraft and informed the Air Force. The PAF then sent the fighters to check the aircraft. The pilot, who has 12 years of experience, did not panic and followed ATC instructions, "the person said.
In 1988, a US warship shot down an Iranian aircraft after it was mistaken for a military aircraft, killing all 290 passengers on board. Following the incident, DGCA automated the process of issuing codes for aircraft. “We have crossed all assigned codes to ensure no duplication. A lesson has been learned, ”said a senior DGCA official.