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Last updated: 6 December 2019
Status:Final
Date:Friday 25 June 1982
Time:10:55 UTC
Type:Silhouette image of generic DC86 model; specific model in this crash may look slightly different
McDonnell Douglas DC-8-62
Operator:Scandinavian Airlines System - SAS
Registration: LN-MOW
C/n / msn: 46131/517
First flight: 1970
Total airframe hrs:40679
Crew:Fatalities: 0 / Occupants: 3
Passengers:Fatalities: 0 / Occupants: 3
Total:Fatalities: 0 / Occupants: 6
Aircraft damage: Substantial
Aircraft fate: Repaired
Location:København-Kastrup Airport (CPH) (   Denmark)
Phase: Standing (STD)
Nature:International Scheduled Passenger
Departure airport:København-Kastrup Airport (CPH/EKCH), Denmark
Destination airport:?
Narrative:
During final preparations for departure, the DC-8-62 aircraft was parked at gate 36 of Apron North at Copenhagen Airport, Denmark. The jetbridge was run out to the main entrance door and crew was onboard reading the check list.
The aircraft was, through a towbar, connected to a tractor. Parking brakes were set on the aircraft and the tractor. Nose gear torque links were disconnected, wheel chocks removed and all landing gear lock pins removed and stowed in the cockpit. Auxiliary hydraulic pumps were on and systems were pressurized.
While refuelling the aircraft a ground mechanic discovered and located a fuel leak in the left hand leading edge wing root area. When the mechanic notified the crew of a possible delay, they discontinued their work and left the cockpit.
Access for repair of the fuel leak required disconnection of two hydraulic lines for the nose gear system. The mechanic depressurized the main hydraulic system by means of the brake pedals, and released the parking brake. Plugs were installed in the open pipe ends.
Jetblast from a Boeing 707 making a 180° turn outside the gate, caused considerably shivering of the DC-8 together with some deflection of its rudder. The aircraft started to move backwards and the nose landing gear slowly retracted. Since the nose gear doors automatically opens during retraction, the aircraft nose section came to rest on the doors, resulting in substantial structural damage.
The main entrance door, which was locked in open position, hit the jetbridge when the aircraft nose section sank to the ground, and was torn off at both hingepoints. The door fell off onto the jetbridge, hitting and slightly injuring a groundhostess who was on her way into the aircraft.

Probable Cause:

Causal factors:
- No landing gear lock pins were installed prior to depressurizing and interrupting the hydraulic system as described under "warning" in chapter 29.00 of the DC-8 maintenance manual.
- Consequences of not depressurizing the emergency steering pressure, and further, capping the return line for the system was not realized by the maintenance personnel.
- When jetblast from a passing aircraft moved the rudder of the DC-8 consequently moving the steering control valve, available emergency steering pressure in the nose gear system was equalized and unlocked the nose gear down lock bungee cylinder.

Classification:

Sources:
» Aircraft Accident Report 1/83


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