MIAMI – Today in Aviation marks the 30th anniversary of an accident which could have easily had a very different outcome. This article will be based on the official report.
On June 10, 1990 British Airways 5390, a BAC One-Eleven, had one cockpit window seperate completely from the aircraft and the Pilot in Command ended up exiting the aircraft during flight.
As the cockpit door had also blown in to the cockpit, the No 3 Purser was able to run into the cockpit and grab onto the legs of the Pilot in Command. The Second in Command was able, with assistance from the Air Traffic Controller, to land at Southampton Airport.
The only injuries were to the Pilot in Command, and one steward, and there were no fatalities.
The Flight Plan, and the Unplanned
Flight 5390 was planned between Birmingham, UK and Malaga, Spain. There were 81 passengers, four Cabin Crew, and 2 Flight Crew on board. The flight took off at 7:20 in the morning, and all was normal until it was climbing to the given FL230.
When it reached about 17,300 feet, there was an explosive decompression due to the windscreen in front of the Pilot in Command (PIC) separating from the aircraft.
As both pilots had loosened their seatbelts, and due to the nature of a explosive decompression, the PIC was sucked out of the window opening. The cockpit door, a far cry from the reinforced doors we see today, blew inwards and fell across the navigation and radio controls.
The Co-Pilot and Flight Attendants
The Co-Pilot immediately put the aircraft into a dive, as the aircraft was not equipped with cabin oxygen systems for the passengers, and was not required to.
As the PIC was only partially out the window, the No 3 Steward was able to grab him around the waist while the Purser removed the door debris. The remaining Cabin Crew prepared the cabin for an emergency landing.
Unfortunately the Steward and Purser were unable to pull the PIC back into the cockpit during flight. With help from the No 2 Steward, they were able to free the PIC legs from the control area and the purser held onto his ankles while strapped into the jump seat until the aircraft successfully landed.
Landing without a checklist
The Co-Pilot had difficulty communicating with the ground due to the airflow in the cockpit. However, overcoming this difficulty, he was able to single handily land the aircraft at Southampton.
He had 1,100 hours flying the BOC One-Eleven, which likely helped him in making the proper decisions and following the proper procedures without checklist reference.
After the successful landing, the passengers disembarked per airstairs, and the PIC was removed by the fire services. The PIC had a broken right arm and wrist, and left thumb, along with frostbite, bruising and general shock. One other steward had cuts and bruising to his arm.
The cockpit windows were not plug-fitted; therefore, the only thing holding them to the aircraft during flight were the screws. This means that if the bolts were to fail, the pressure of the air within the cabin at altitude would be enough for the window to be separated from the aircraft.
There was no airworthiness requirements for plug fit windows at the time of the accident.
The aircraft in question, G-BJRT, was in for maintenance directly before the accident flight, and this was the first flight after the aircraft had been returned to service.
The windshield required 90 bolts, which should be A211-8D bolts. However, 26 bolts recovered were A211-8C bolts, which are both thinner, and have a coarser thread size.
Four other bolts recovered were A211-7D bolts, which are shorter than the required bolts. The anchor nuts are of a unified fine thread, which is signified by D in the bolt name. This indicated that the bolts were not installed as designed.
When investigators looked further into the bolts used on the windshield, they found that even the old bolts removed were mostly not of the required size – 78 of them were A211-7D bolts which were shorter than recommended.
Due to this discovery that even the previously installed bolts were not to specs, special checks were conducted on the other BAC One-Elevens in the fleet, and it was found that two other aircraft had windscreens installed with the shorter bolts.
The UK Air Accident Investigation Board had a number of recommendations. Some of these were:
- That the regulatory authorities should re-evaluate the self certification to aircraft engineering safety critical tasks.
- BA should review the Quality Assurance system, shop floor education, and introduce job descriptions of engineering grades.
- Recommended that BA conduct an audit into the work practices at Birmingham.
- The airworthiness authorities should review training and testing of engineers as well as the need for corrective glasses.
- Recommended that the airworthiness authorities introduce regular training for Air Traffic Controllers with regards to emergency situation handling.