The McDonnell Douglas DC-10, a widely used aircraft during the 1970s and 80s, was a marvel of its time, offering remarkable capabilities and efficiency for air travel. However, lurking beneath its impressive façade was a design flaw that would lead to disastrous consequences. This is no less than the problematic cargo door of the DC-10.
Time to talk about the design issues, the harrowing accidents that stemmed from these shortcomings, and the subsequent modifications that finally resolved these safety concerns.
A Unique Cargo Door Design
Unlike conventional inward-opening plug doors, the DC-10 was designed with outward-opening cargo doors. This allowed the cargo area to be completely filled without sacrificing interior space when the doors were open. However, to counteract the outward force from pressurization at high altitudes, these doors required heavy locking mechanisms. If the door lock malfunctioned, there was a higher potential for explosive decompression.
American Airlines Flight 96: A Warning Sign
On June 12, 1972, American Airlines Flight 96 experienced a cargo door failure above Windsor, Ontario. The door seemed secure before takeoff, but the internal locking mechanism was not fully engaged. When the aircraft reached approximately 11,750 feet, the door blew out, causing an explosive decompression that collapsed the cabin floor and severed many control cables. Miraculously, the crew managed to land the aircraft safely.
The U.S. National Transportation Safety Board (NTSB) investigation found the cargo door design to be dangerously flawed. The door could be closed without the locking mechanism fully engaged, and this condition was not apparent from visual inspection or cockpit indicators. The NTSB recommended modifications to make it obvious when the door was not secure and adding vents to the cabin floor to equalize pressure during decompression. Although many carriers voluntarily modified their cargo doors, no airworthiness directive was issued due to an agreement between the FAA and McDonnell Douglas.
The Tragic Crash of Turkish Airlines Flight 981
On March 3, 1974, a similar incident occurred with Turkish Airlines Flight 981, which resulted in the deadliest air crash at the time, with 346 deaths. The cargo door had not been fully locked, though it appeared so to both the cockpit crew and ground personnel. The aircraft’s seating configuration exacerbated the decompression effects, causing the cabin floor to collapse and the control cables to be severed, making the aircraft uncontrollable.
Investigators found that the DC-10’s relief vents were not large enough to equalize pressure during explosive decompression. A special subcommittee of the United States House of Representatives investigated the cargo-door issue and the FAA’s certification of the original design. An airworthiness directive was finally issued, and all DC-10s underwent mandatory door modifications.
Lessons Learned and the DC-10’s Safety Improvements
After the FAA-approved modifications were made to the DC-10’s cargo door, no more major incidents related to the door occurred. These tragic accidents served as a stark reminder of the importance of rigorous design testing and oversight in aircraft manufacturing. The lessons learned from the DC-10’s problematic cargo door have undoubtedly contributed to the overall improvement of aircraft safety in the years since.
First love never dies. I fell in love with airplanes and aviation when I was a kid. My dream was to become a pilot, but destiny led me to another path: to be an aviation digital media content creator and a small business owner. My passion for aviation inspires me to bring you quality content through my website and social accounts. Aviation is indeed in my blood and blog!
