What happened
On June 9, 2017, an Air India Airbus A320-231, registration VT-ESL, was performing a scheduled flight from Delhi to Jammu when it overran the runway at Jammu Airport. During the approach, the crew received a "Brake Auto Brake Fault" warning after extending the landing gear. Following established procedures, the crew opted to proceed with the landing using manual braking.
The aircraft's approach became unstable below 500 feet, and the aircraft floated above the runway surface for several seconds. The main landing gear touched down approximately 2,400 feet from the runway threshold at a ground speed of 145 knots. During the landing roll, the aircraft experienced the simultaneous burst of four main landing gear tyres. Despite the application of full thrust reversers and manual braking, the aircraft could not be stopped within the paved surface, eventually exiting the runway and coming to rest in unpaved ground near the airport perimeter wall.
Following the overrun, smoke was reported in the rear of the cabin, prompting an emergency evacuation of the 137 passengers and 4 cabin crew via escape slides. No injuries were reported.
The investigation
AAIB India examined the flight data, cockpit voice recordings, and aircraft components to determine the sequence of events. The investigation focused on the mechanical failure of the brake servo valve, the stability of the final approach, and the effectiveness of the braking application. Investigators also reviewed the serviceability of the aircraft's emergency equipment and the airport's runway safety area.
Findings
- The aircraft's approach was not stabilized, as the aircraft flew below the glide slope at approximately 180 feet altitude.
- A malfunction in the brake servo valve triggered the initial auto-brake fault warning.
- The touchdown was delayed due to a prolonged flare and floating period, resulting in a high ground speed at the threshold.
- Improper brake application and low deceleration rates contributed to the inability to stop the aircraft.
- The burst of four main landing gear tyres significantly hindered deceleration.
- The airport lacked a Runway End Safety Area (RESA) for runway 36, bringing the aircraft within 53 feet of the perimeter wall.
- An inspection of the emergency escape chutes revealed that both the chutes and the pressure bottles had exceeded their manufacturer-recommended service life.
Safety action
- The investigation recommended that the DGCA reiterate safety circulars advising flight crews to execute a go-around whenever an approach is not stabilized, particularly at performance-limited airfields.
- Instructions were recommended for all operators to ensure the timely inspection and replacement of escape chutes before their expiration dates.