The McDonald Douglas DC 10.Engineering Disaster

The DC 10 was the first commercial airliner McDonald Douglas had manufactured since the two companies,McDonald Aircraft Corporation and Douglas Aircraft Corporation had merged in 1967.It was also the company's first wide body airliner,designed to compete with the Lockheed L-1011and the slightly larger Boeing 747. McDonald Douglas had invested more than a billions dollars in designing and developing the DC 10.To say that the future of the company depended upon the success of the DC 10 would in no way be an understatement.

The airliner began commercial service with American Airlines on August 5 1971,with a flight between Los Angeles and Chicago. The DC 10 would begin service with United Airlines two weeks later on August 19. It would join the fleets of the airlines of the world over the next few years.

But the DC 10 had a design flaw,that had been first noticed on early test models.The aft cargo door was outward opening with a locking mechanism that secured the door while the plane was in flight.The locking mechanism on the cargo door was not fail safe. In fact during tests,it had been shown that the locking mechanism on the door could be force into place even if the door had failed to close properly. The only way to make the cargo door fail safe would be to make it a plug type door. With a plug type door,the door itself is larger than the cargo hold opening,and once the door is closed and the aircraft pressurized,it is impossible for this type door to blow out. But a plug type door,by opening inward, causes the loss of cargo space,and the loss of those profits the plane would be able to make,if it had a cargo door that opened outward. The added cargo space the outward opening door provided was a selling point that McDonald Douglas pointed to in the sales brochure for the DC 10's. So even though the designers were aware of this serious problem with the outward opening cargo door on the planes,they allowed the DC 10 to go into commercial service.

The first mishap occurred before the planes had completed a year of service. On June 12 1972 in what would become known as The Windsor Incident throughout the aviation industry,an American Airlines DC 10 lost its aft cargo door soon after taking off from Detroit. Prior to the planes departure,a airport employee had had trouble closing the cargo door on the plane,but had managed to force the locking mechanism into place.

The loss of the cargo door caused the plane to suffer a explosive decompression which caused the cabin floor to partially collapse. There were only 56 passengers on the jumbo jet for the flight that day,and that's one of the reasons it's believed the floor only partially collapsed.

But even with floor only partially collapsed,all the plane's hydraulic lines and control cables that enabled the flight crew to control their mammoth aircraft,ran through the floor of the cabin,and had been damaged. The crew in the cockpit discovered that they had a very limited range of control of the plane. The crew was able through skill and training, to safely land their disabled aircraft by manipulating the limited controls that still remained. But it was a very close thing,and it should have started red flags waving about the safety of the DC 10.

In the ensuing investigation by the National Transportation Safety Board,(NTSB) the board found that the design of the DC 10's cargo door "was dangerously flawed". It's investigation showed that the cargo door lock could be forced closed and while not being closed,and the lock gave every external sign that it was,in fact locked properly in place.The Board recommended that the door's be retrofitted with a new door with a newly designed lock that was fail safe.The NTSB also recommended that vents be installed in the planes cabin floor to aid in venting the cabin in the case of an explosive decompression.

The NTSB reported these facts to the Federal Aviation Administration (FAA) who's job it is to oversee the airline industry.The FAA issued a bulletin advising the Airlines that used DC 10's in their fleets of the suggested fixes. But by only recommending that the repairs by made the NTSB and the FAA let the airline industry decide for itself when or even if the repairs would be carried out.The FAA had the option of issuing an Air Worthiness Directive,which would have grounded the DC 10's worldwide and would have made the repairs mandatory before the planes could carry passengers again.

The FAA's job is to promote the American aviation industry and to protect the airline's customers,which is a mission that sometimes put the FAA in a situation where it's working at cross purposes. By grounding the DC 10's worldwide, a move which would tarnish the planes reputation with the flying public,was something the people at the FAA tried to avoid.But to not ground the planes put people lives at risk. The FAA choose to trust the airlines to make the needed repairs themselves.

On March 3rd 1974 a Turkish Airlines's DC-10 left Paris bound for London with 333 passengers and a crew of 13. The Turkish Airlines hop to London was usually only about half full, but today the flight was sold out due to a strike at British European Airways that had people scrambling to find a seat on any available flight into London. Less than 15 minutes into the flight the aft cargo door blew off of the plane causing an explosive decompression and,with a full passenger load the floor of the plane's cabin collapsed into the cargo hold below. it had to have been a nightmare for the people in the plane's cabin!

The flight crew faced with the loss of all controls of the aircraft tried in vain to regain some degree of control of the stricken jet. But when the cabin floor collapsed, all three hydraulic lines and all the flight control cables were severed. The plane went into a dive and crashed into a forest at almost 500 miles per hour. The crash scene was beyond description.The plane had literally disintegrated on impact.Of the 346 people on board the Turkish airliner,only 40 bodies were ever positively identified,as bodies.

French and Turkish investigators soon started to hear whispers about The Windsor Incident. You can imagine the investigators reaction when they discovered that officials in America were well aware of the defective door,and yet had allowed the planes to continue to operate.

The world's fleets of DC 10 were grounded until the doors could be repair in such a fashion as to make them fail safe. All later models of the DC 10 would have a redesigned fail safe cargo door. But it was to late. The damage to the planes reputation had been done. The McDonald Douglas Corporation never realized the sales of the DC 10's that the company had predicted. Most airlines canceled any plans they may have had buy the DC 10. McDonald Douglas was able to sell Federal Express and United Parcel Service and other package carriers enough of the redesigned DC 10's to keep the company in business.

The McDonald Douglas Corporation was acquired by Boeing in 1997