ARMCHAIR NTSB: Squawk Codes Gone Wrong

Squawk codes are transponder settings used to identify aircraft in flight. When operating in controlled airspace, every aircraft uses a squawk code assigned to them by ATC. There are 3 codes that are universally used to signal a problem onboard an aircraft: 7500 for hijacking, 7600 for loss of radio communications, and 7700 for an emergency onboard.

A jetBlue flight from JFK recently had some communications failure and, unable to use the radio to contact the tower to alert them of the problem, attempted to switch the transponder code to 7600. When ATC sees that an aircraft is having comms trouble, they will give them specific instructions to rectify the situation or, if need be, send a vehicle to the aircraft to tow them to a safe location.

However, the jetBlue crew made what I think is quite a critical error: they set the transponder code to 7500 instead of 7600. This prompted a massive security response resulting in the aircraft being stormed by security personnel, even though the crew was able to eventually reestablish comms with the tower and requested a return to the gate. However, security insisted on inspecting the aircraft.
They eventually returned to the gate and a new flight crew took the A321 to LAX with a four-hour delay.

WHAT COULD’VE BEEN DONE TO PREVENT THIS?
Well, not much. The squawk codes are universally-recognized codes, and coordinating a response and retraining millions of pilots to new squawk codes that can’t be mistaken is a logistical nightmare. If one recalls correctly, the 7500 code for hijack has been a source of trouble in the past, most notably, the Korean Airlines Flight 85 that mistakenly set their transponder to 7500 during the September 11 attacks, even though the aircraft was secure and a translation error was to blame for the mishap. Private pilots sometimes talk of mistakenly setting their transponders to 7500 instead of 7600 when a radio goes out, resulting in mountains of paperwork and disciplinary action.

I would not change squawk codes. These are invaluable to safe operations and if there is indeed a hijacking, changing the transponder to 7500 is a discreet way to alert authorities that there’s a problem onboard. I think it really is up to the pilots to be sure they have the awareness to push the correct buttons to set the transponder correctly. Given the fact in this situation the jetBlue flight was approaching the departure runways, if the crew suddenly stopped with no communication with the tower, and with the transponder suddenly switching to hijack, I feel the tower had no choices but to respond the way they did to make sure there wasn’t someone trying to take over the aircraft while it was on the ground.

-Zach