US investigators state that 22 occupants of a JetBlue Airways Airbus A320 were injured during an in-flight pitch upset which subsequently triggered a mass grounding of Airbus jets for a software modification.
The incident, on 30 October last year, occurred as the aircraft was cruising at 35,000ft over the Gulf of Mexico.
It resulted in a 100ft loss of altitude, says the National Transportation Safety Board in preliminary findings.
The safety board states that the excursion took place in “smooth air and clear weather”.
Eighteen passengers and four cabin crew members sustained minor injuries. The aircraft – which had 124 occupants, and was operating a Cancun-Newark service – diverted to Tampa.
The elevator and aileron computers were sent to French aerospace firm Thales for examination, while other components were transferred to their respective manufacturers for testing and data extraction.
Airbus subsequently identified the elevator and aileron computer software as a “possible contributing factor”, says the safety board, although investigators have yet to confirm the cause of the upset.
Analysis by Airbus discovered a possible vulnerability in the software to data corruption – such as that from a solar radiation particle strike – and thousands of A320- and A320neo-family jets were grounded in late November pending reversion to a previous software standard.
The precise nature of the vulnerability, and the trigger for the JetBlue incident, have yet to be confirmed.
Investigation of the occurrence is continuing.
