MCDONNELL DOUGLAS MD 11F near St. Louis, MO — 2015-02-24

Probable cause

a partial inflation of the 1L escape slide/raft due to undetermined reasons resulting in insufficient capability to support the weight of the crewmember.

NTSB narrative

During cruise flight, the crew received a fire warning from the cargo compartment indicating that the fire suppression system had activated, along with hearing loud sounds from the cargo compartment. The flight crew elected to divert to St. Louis. Although the activation of the fire suppression was a false alarm, the decision to divert was prudent and correct. During the approach the crew made the decision to evacuate the airplane after landing, briefed the passengers in the courier area, and reviewed the evacuation checklist in the Quick Reference Handbook (QRH). The diversion and subsequent landing were performed without issue. After exiting the runway, and bringing the airplane to a stop in a safe area, the crew initiated an emergency evacuation using the left forward door (1L). The door opened, however, the 1L escape slide/raft did not fully deploy, appearing to be hung up on a strap. The first officer attempted to free it and the fire/rescue crew pulled on the slide and it appeared to inflate. However, because the slide inflation sequence had been interrupted, it was significantly underinflated and unable to support the weight of the crewmember, resulting in a serious injury. Post-incident examination of the 1L slide/raft was unable to determine the causes for the slide/raft to not inflate to full extension.

Analysis

Primary failure mode

Mechanical failure

First missed decision gate

Crew could have opted for a different evacuation method after landing.

NTSB coding

• Sys/Comp malf/fail (non-power) · Standing

Evidence available

• 12 docket documents

Docket documents12

• Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1form
• Captain Statementinterview
• First Officer Statementinterview
• Jumpseat 1 Statementinterview
• Jumpseat 2 Statementinterview
• Statement of Party Representatives to NTSB Investigation - Air Cruisersinterview
• Statement of Party Representatives to NTSB Investigation - Fedexinterview
• Operations - Door Trainerother
• Operations - Emergency Equipment Trainingother
• Operations - QRH Excerptother
• Survival Factors - Errata to the Slide/Raft Teardown Reportreport
• Survival Factors - Slide/Raft Teardown Reportreport