Douglas DC-8-73 N831AL

Summary

On 17 June 2000 at about 13:12 local time, a Douglas DC-8-73 registered N831AL, operated by Emery Worlwide, was involved in an incident near Seattle, Washington, United States. 5 people were on board and nobody was injured. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

17 June 2000 at 13:12

Classification

Incident

Location

Seattle, Washington, United States

Coordinates

47.4403, -122.2798

Aircraft

Douglas DC-8-73

Registration

N831AL

Category

Airplane

Engines

4

Operator

Emery Worlwide

Operating rule

Part 121: Air Carrier

Purpose of flight

Unknown

Phase of flight

Not recorded

Route

Dayton → Unknown

Aircraft damage

Not recorded

Weather

VMC

Light

Dawn

NTSB number

SEA00IA108

Nobody was injured.

Auxiliary hydraulic pump leak resulting in a failure of the hydraulic system.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full NTSB narrative

The flight crew reported that while in cruise flight at flight level 310 (31,000 feet) they noted a loss of hydraulic fluid quantity in the aircraft's main hydraulic system reservoir. Shortly after powering the auxiliary rudder pump, the crew felt a '...chattering and feedback with the rudder pedals'. The crew also reported that the rudder momentarily deflected to the left. Post flight inspection of the aircraft's hydraulic system indicated that the auxiliary hydraulic pump was leaking fluid and that the hydraulic fluid quantity was at 'standpipe level'. Examination of the auxiliary hydraulic pump assembly revealed that the gasket located between the hydraulic pump mainframe and the AC electric drive motor, had failed. Further examination of the hydraulic pump subassembly revealed that the rate piston (part number 56909) was 'frozen' in the extended position. A frozen rate piston (in the extended position) could result in high internal case pressures capable of exceeding the manufactures specifications and the specifications of the gasket. Heavy scoring on the piston and the piston housing, with evidence of contamination were also noted.

Quoted verbatim from the NTSB record.