On June 30, 1988, a Mcdonnell Douglas DC-8-73F (registration N791FT) operated by Emery Air Freight was involved in an aviation accident near Seattle, WA. Investigators recorded the probable cause as: A ruptured number three hydraulic pump pressure line and an improperly rigged emergency hydraulic pump control arm, which resulted in a loss of hydraulic fluid and locked brakes during landing. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
Aircraft experienced hydraulic fluid loss during flight, prompting the crew to execute emergency procedures. The landing caused tire blowouts due to locked brakes.
What happened
During the flight, the crew observed indications of a loss of hydraulic fluid. In response, they followed standard procedures outlined in the crew manual. An emergency hydraulic system was utilized to lower the flaps for landing. The aircraft landed with four right-side brakes locked. This resulted in the tires blowing out and the wheels becoming ground flat.
The investigation
An examination of the aircraft revealed a ruptured number three hydraulic pump pressure line. Investigators also found that the emergency hydraulic pump control arm had been improperly rigged.
Findings
The primary factors contributing to the incident were the rupture of the hydraulic pump pressure line and the improper rigging of the emergency hydraulic pump control arm. These mechanical failures led to the loss of hydraulic fluid and subsequent brake issues during landing.
Probable cause
A ruptured number three hydraulic pump pressure line and an improperly rigged emergency hydraulic pump control arm, which resulted in a loss of hydraulic fluid and locked brakes during landing.
