Aircraft type: BAC One-Eleven
Operator: British Airways
Flight Origin: Birmingham Airport (BHX/EGBB), United Kingdom
Destination: Málaga Airport (AGP/LEMG), Spain
Date of Accident: June 10, 1990
Type of Incident: Faulty Maintenance; Explosive Decompression
Persons Involved:
Pilot: Captain Tim Lancaster and co-pilot Alastair Achison
Crew: 6
Passengers: 81
Survivors: All 87
Fatalities: 0
The pilot, Tim Lancaster, was forced halfway out of the cockpit when an improperly built windscreen panel collapsed. His head and torso were out, at 17,300 feet, being hit by 300mph winds, while his legs stayed inside, held tightly by flight attendants. Co-pilot Alastair Atchison made an emergency descent but could not communicate with air traffic control due to the noise of moving air. Lancaster landed quickly in Southampton, where he was treated for frostbite, discomfort, and a broken arm.
CAUSE
After the investigation, the following problems are discovered:
– Badly fitted windscreen panel
–Wrong bolts
When the windscreen was reconfigured to the plane the night before, the inaccurate bolts were used to mount it; they were approximately half a millimeter too short and had cracked under intense air pressure. It has been discovered that 84 of the 90 windscreen retention bolts were 0.026 inches (0.66 mm) too small in diameter, while the other six were 0.1 inches (2.5 mm) too short.
The bolts had completely replaced other inaccurate ones; the engineer had replaced the previous bolts with new ones on a like-for-like basis when operating under pressure and without examining manuals.
– Faulty Design of the Windscreen
During the flight, the air pressure difference between the cabin and the outside seemed too great, causing the windscreen to malfunction. The occurrence also highlighted a design flaw in the aircraft in which the windscreen was installed from the outside of the aircraft, putting more pressure on the bolts than if they were locked from the inside.
– Management Failed to Inspect
The investigators also found flaws in British Airways’ regulations, requiring checking or inspection by a second person for such a crucial job. Finally, prosecutors criticized the local Birmingham Airport administration for failing to oversee the shift maintenance manager’s working practices. Stuart Culling was the AAIB’s chief prosecutor.
CORRECTIVE MEASURES
- As a precautionary measure, British Airways planes’ windscreens are now protected by bolts from the inside rather than the outside, giving them less pressure.
RECOMMENDATIONS
The investigators of the British Airways Flight 5390 Accident recommended that British Airways should:
– Evaluate their product safety framework and allow engineers to provide recommendations.
– Consider whether it is necessary to add work requirements and selection criteria for engineering levels Shift Maintenance Manager and above.
– Examine their product sample policy to obtain independent assessment of quality and execute an in-depth audit of Birmingham Airport’s work practices.
As for the Civil Aviation Authority, they are suggested to:
– Determine the long-term feasibility of self-certification for safety-critical tasks on aircraft.
– Examine the nature and intent of the FOI 7 Supervisory Visit.
– Recognize the need for engineers to be qualified and tested regularly.
– Understand the need for protective glasses if prescribed when conducting aircraft engineering duties.
– Ensure that, before receiving an air traffic control rating, an applicant completes an approved course that includes instruction in both practical and realistic emergency management.