DCA11FA052

A failed utility pipe caused erosion of the soil beneath the reinforced concrete ramp resulting in a void beneath the ramp surface. When the airplane taxied over this area of the ramp, the left main landing gear penetrated the concrete and sank into the void. Without the support of the soil beneath the concrete, the ramp surface was not strong enough to support the accident airplane.

HISTORY OF FLIGHT On May 6, 2011, at 0200 central daylight time, a Boeing 737-800, registered as N12221, was taxiing from a paint facility to the runway for an anticipated takeoff from Mid Delta Regional Airport (GLH), Greenville, MS. During taxi, about 100 to 150 yards from its parking spot, the aircraft's left main landing gear assembly sank into the ramp surface. The two pilots onboard were not injured. No other people were on the airplane. The airplane was substantially damaged. The airplane was registered to and operated by Continental Airlines under the provisions of 14 Code of Federal Regulations Part 121 and the flight was to be operated as a non-revenue repositioning flight to George Bush Intercontinental Airport (IAH), Houston, TX. According to the captain, he and the first officer immediately initiated the evacuation checklist and exited the airplane. DAMAGE TO AIRPLANE The left main landing gear strut failed and the airplane settled onto the left engine and rear fuselage, damaging the engine cowl and rear fuselage sheet metal. AIRPORT INFORMATION According to FAA personnel who examined the ramp after the event, the thickness of the concrete varied from 6 to 6 1/2 inches and was reinforced by 3/4 inch square rebar. A large void was found directly beneath the area of sunken ramp pavement. The void was about 6 feet deep and 20 feet across. Further examination of the void revealed the presence of a failed utility water pipe, which was found to have failed at a pipe joint.