What happened
On 13 July 2021, an Airbus A319-111, registration G-EZBD, was performing a non-revenue flight from London Luton Airport. The aircraft had been parked for nearly a month following its previous operation in Edinburgh. During the takeoff roll from runway 07, the crew noted that the engines took longer than usual to spool up. As the aircraft accelerated, the co-pilot performed a cross-check of the airspeed indications against the Integrated Standby Instrument System (ISIS).
While the ISIS indicated an increasing speed, the co-pilot's Primary Flight Display (PFD) remained stuck at 40 kt. As the aircraft reached approximately 80 to 90 kt, the co-pilot alerted the commander to the discrepancy. Due to the aircraft's light weight, it was accelerating rapidly. The commander, observing his own airspeed climbing above 100 kt, made the decision to abort the takeoff. The rejected takeoff was initiated at 120 kt, which was 11 kt above the calculated V1 speed. Despite the high-speed nature of the abort, the aircraft came to a halt approximately 350 m before the end of the runway.
The investigation
The AAIB examined the flight data recorder, cockpit voice recorder, and aircraft systems. The investigation focused on the cause of the airspeed discrepancy and the engine performance concerns raised by the crew. Maintenance records showed that pitot covers had been applied and removed during various periodic checks while the aircraft was parked.
Upon inspection of the pitot systems, engineers performed a flush of all three systems. During this process, debris was removed from the co-pilot's pitot probe. Although the material was not recovered for analysis, its removal was noted. Subsequent leak checks of the pitot systems were found to be satisfactory.
Findings
- The airspeed discrepancy was caused by a blockage in the co-pilot's pitot tube.
- The blockage likely occurred during the period the aircraft was parked, though the exact timing could not be determined.
- The aircraft was operating at a significantly low takeoff weight, which provided the necessary performance margin to stop safely despite the high-speed rejection.
- The crew had been briefed on the potential for pitot obstructions due to the aircraft's recent long-term parking and had specifically planned to cross-check airspeed indications.