An operator of a model 737-500 airplane recently experienced retraction of a 737 nose landing gear while the airplane was on the ground. A ground service worker, who was near the nose landing gear at the time of retraction was killed.

The operator of the airline reported to Boeing; upon entering the cockpit for pre-flight, the captain noticed the nose gear warning light on the P2 panel and notified ground service. Ground service attempted to insert the nose gear ground lock pin, but was unable to because the holes were not aligned. The ground service employee then removed the nose wheel chocks and the gear retracted, killing the employee.

The airplane had recently undergone repair of a leaking hydraulic pressure tube approximately five feet from the connection to the landing gear transfer valve. In order to perform the repair both the pressure and return tubes were disconnected from the landing gear transfer valve. These tubes were then reconnected to the wrong ports by different personnel after a maintenance shift change. The results was that when the hydraulic system was pressurised and the cockpit landing gear handle was in the «down» position, the landing gear was commanded «up». When the nose gear chocks were removed the landing gear retracted. The main gear lock pins were installed at the time of the incident.

Operators are reminded, when removing tubes from the landing gear transfer valve, to label the tubes as called for in the maintenance manual.