A Boeing 747-45EM had arrived at London-Heathrow Airport after a flight from Bangkok Thailand on a scheduled passenger flight. After the passengers and crew had disembarked the aircraft was towed to a remote stand.
The aircraft "on its nose" (Source: aviation-safety.net © Unknown)
Maintenance staff were troubleshooting a hydraulic leak in one of the main landing gears. After the replacement of a seal in the landing gear hydraulic system the system needed to be leak checked by pressuring the landing gear hydraulic system. To pressurise part of the hydraulic system of the landing gear it was necessary to place the landing gear lever in the "Gear Up" position. To prevent the landing gear from actually retracting during this process the landing gears are "safetied" using Landing Gear Safety Pins.
When installed they prevent the landing gear from retracting when the landing gear lever is placed in the "Gear Up" position.
In this case, the maintenance crew used a non-standard nose landing gear safety pin which was produced locally. This pin lacked a safety feature that would prevent the safety pin from falling out of the landing gear. The non-standard safety pin was not installed correctly and rested on the (closed) nose landing gear bay doors. When the landing gear lever was placed in the up position the nose landing gear bay doors opened, allowing the nose landing gear safety pin to drop from the landing gear. This allowed the nose landing gear to retract and the aircraft to come to rest on the lower fuselage.
The aircraft "on its nose" (Source: aviation-safety.net © Unknown)
The (reported) damage to the aircraft was extensive;
Nose landing gear doors
The nose section of the lower fuselage
The nose landing gear bay was structurally damaged
Entry door (cam to rest on access steps)
The right lower fuselage was punctured by the ground power unit
One member of the groundcrew received injuries to his head in the incident, requiring some stitches.
With the aid of airbags, the aircraft was lifted up and the nose gear was extended, after which a correct nose landing gear safety pin was installed. Subsequently, the aircraft was towed to a hangar for repairs to be carried out.
The damage cost was estimated to be around $ 7.000.000 and required approximately 4 months to repair. The aircraft reportedly was returned to service on the 22nd of September 2004. **Editorial note**
V2 Aviation - Training & Maintenance has not been able to obtain an official investigation report into this incident. This blog was written using unofficial information available on the internet. In case of inconsistencies in this blog please get in touch with us via the comments section or the contact page.
Very very lucky no one was killed.