This article was written for AirlineReporter by Kris Hull.
Starting tomorrow, the last Douglas DC-10 will start its farewell tour as the last passenger DC-10. Biman Bangladesh Airlines will fly to Birmingham, UK, by way of Kuwait and then offer scenic tours before it is finally ferried to a final “resting” location in the US. Our own Bernie Leighton will be covering these events from Bangladesh and beyond, but before we tell the last chapter of this majestic aircraft’s life, we wanted to start at the beginning with this historical look at the DC-10.
The birth of the wide-body airliner as we know it today can be traced back to one event in the early 1960’s: The United States Air Force’s request for proposals for the CX-HLS, the program that would ultimately become the C-5 Galaxy. Lockheed won the CX-HLS competition, and as legend would have it, Boeing would strike gold when they converted their design into what we know today as the 747. However, that is not quite 100% true, and Boeing was not the only company to transfer design philosophies from the CX-HLS to the commercial market.
Upon losing the USAF contract, the powers that be at Douglas aircraft immediately started altering their ideas to fit the commercial market, and a race was starting to see who would bring the first wide-body aircraft to market. Like Boeing, Douglas also studied the possibility of a double deck design, capable of seating upwards of 500 passengers, and also like the Boeing airliner concept, Douglas moved from a high, shoulder-mounted wing to a low-wing design.
Douglas studied several different designs, including the D-950 and D-952 concepts, which would have carried 525 and 454 passengers, respectively. However, as further studies at the time decided, there was really no market for a large number of large-sized aircraft, and after Douglas shopped around their proposal for a large, four-engine aircraft to various airlines, including Pan Am (who at the time had just signed an order with Boeing for 25 747s), Douglas management wisely decided to take a step back and consider a detailed look at what the market predicted.
Around this same time, Douglas Aircraft merged with McDonnell Aircraft to form the McDonnell Douglas Company, and the new management team decided to make the DC-10 airliner program a priority. The project team aired for criteria spelled out by American Airlines; a twin-engine airliner that could carry at least 250 passengers and 5,000 lbs of cargo 1,850 miles, cruise at Mach 0.80, and could meet this criteria from the short runways at New York’s LaGuardia Airport. After deciding to tackle this request, Douglas engineers, on their own merit, decided to pitch the idea of a three-engine aircraft, arguing that it would be no more costly than a twin, and would offer better performance in hot weather.
Douglas convinced American of the three-engine layout after seeking the advice of other airlines, and the revelation that Lockheed was developing a similar aircraft: the Lockheed L1011. As a result, in July 1967, American issued a refined set of requirements: A tri-jet capable of transcontinental flight, with full payload and a trip time within minutes of the 747, comparable economics to the 747 between New York and San Francisco, and a Mach 0.85 cruise speed at 35,000 feet.
With this revised criteria from an airline, the McDonnell Douglas board gave its permission to launch the DC-10 in November, 1967. This was officially realized in February 1968, when American Airlines placed an order for 25 aircraft, with 25 options. Two months later, the program was launched when United Airlines placed an order for 30 aircraft, and 30 options. With orders in the books, the process of fine-tuning the design and moving towards production could begin.
Douglas chose the GE CF-6 high bypass turbofan, since Pratt & Whitney was heavily involved in producing engines for the war effort in Vietnam, and the JT9D was the sole engine choice at the time on the 747. Rolls Royce was in an awkward position, since they had a sole source contract with Lockheed for the powerplant on the L1011. Douglas engineers studied various options for locating the third engine. Looking at everything from an S-duct in the tail (Lockheed chose this for the L1011), to having the engine buried in the tail cone with a bifurcated duct that wrapped around the base of the vertical fin. The design that the engineers finally chose was to have a straight pass through duct mounted on top of the tail cone, creating a so-called “banjo”.
Wind tunnel tests proved that this arrangement would yield better performance results, and would also ease maintenance and spares issues. By placing the engine on top of the tail cone, and having all engine attach fittings in the top of the banjo, one engine could be used in any of the three engine locations, with only 45 minutes worth of work needed to reconfigure an engine off a wing for mounting in the tail.
Douglas had originally planned on having three models of the DC-10; the DC-10-10, 10-20, and the 10-30. The base model (the 10-10) was a transcontinental aircraft, and was not optimized for intercontinental routes. The 10-20 was to be the first of the intercontinental DC-10s, powered by the Pratt & Whitney JT9D. Lastly, the DC-10-30 was to be the same as the -20, however it was to be powered by up-rated versions of the CF-6. The main distinguishing features of the -20 and the -30 were the addition of a third main landing gear leg, mounted directly on the centerline of the aircraft.
Northwest Orient was the first airline to order the intercontinental model in October 1968, and they chose the JT9D engines for fleet commonality with their 747s already on order. Only one other carrier would order the -20, and that was Japan Airlines. Now, I am sure that many aviation fans here are thinking that no DC-10-20 ever saw service, and you would be technically correct. Prior to delivery of the first -20 to Northwest, according to popular legend, Northwest and Japan Airlines both approached Douglas saying that they did not want their aircraft to seem inferior to the -30 model, and wanted their aircraft to appear to be the best and latest model of the DC-10. Douglas gave in and designated the DC-10-20 as the DC-10-40.
The first DC-10, a -10 model, made the type’s first flight on August 29th, 1970 from Long Beach, California, just one month after the official rollout on July 23rd. A year later, after a flight test program that spanned 1,500 flight hours over 929 flights, using 5 aircraft, the DC-10 received its FAA Type Certificate on July 29th, 1971. That same day, the first two aircraft were officially delivered to two inaugural customers: American Airlines and United Airlines. The first passenger flight of the type occurred just a week after the first delivery, when American flew a round trip flight from Los Angeles to Chicago on August 5th, using N103AA, the 5th DC-10 built. United followed suit on August 16th, with a round trip from San Francisco to Los Angeles using N1802U. Deliveries quickly followed to other airlines, and soon the DC-10 could be seen on routes all over the United States and, for that matter, the world. Entry into service was smooth; however, the aircraft soon gained a reputation that no one wants for any aircraft.
On June 12th, 1972, the DC-10 experienced its first major incident, and a serious design flaw was uncovered. N103AA, the same aircraft that just less than a year before completed the type’s first passenger flight, was operating American Airlines Flight 96 between Detroit and Buffalo. Just after departure, as the aircraft was passing through 11,750 ft, the aft cargo door explosively departed the aircraft. The resulting decompression caused the floor over the cargo compartment to cave in, damaging the flight control cables that passed through the area. Parts of the door also impacted the horizontal stabilizer of the aircraft.
Upon a safe landing back in Detroit, investigators found that the door on this particular aircraft had been difficult to latch prior to departure. The ground crew member stated that he had to use more force than normal to latch the door. He also noted that the pressure relief vent door, a smaller door to relieve any aircraft pressurization prior to normal opening of the door, was not fully seated closed. Upon investigation of the door, which was recovered intact from Windsor, Ontario, it was discovered that the door latch never engaged, and moved just enough to cause the “Door Open” warning light to extinguish in the flight deck – the door appeared to be closed. Following this incident, McDonnell Douglas immediately issued a service bulletin to modify the doors, but airlines were not mandated to make the repair. The FAA also failed to issue an Airworthiness Directive, which would have made the Douglas modifications required before the airplane could fly again.
The type soldiered on for two more years before the cargo door issue came back to haunt McDonnell Douglas, this time with disastrous results. On March 3rd, 1974, Turkish Airlines Flight 981, operated by TC-JAV, departed Paris Orly Airport bound for London with a full load of 346 passengers and crew. As the aircraft was climbing out of Paris, muffled, panic-filled calls came over the ATC frequency. Turkish Flight 981 had been lost with no survivors over the Ermenonville Forest outside of Paris. Investigators soon discovered that the cause of the crash was the rear cargo door opening in flight. Pieces of wreckage were found that included the intact door, still attached to parts of the aircraft skin and cabin floor structure. The investigation soon revealed that a similar scenario to the American Airlines incident nearly two years prior had occurred, and this time, the FAA acted. McDonnell Douglas immediately redesigned the door, and added small windows that would allow the ground crew to visually verify that the latch pins were engaged. The DC-10’s reputation was already tarnished and the aircraft was in the public eye for the wrong reasons.
The next major incident would come on May 25th, when American Airlines Flight 191, operated by N110AA, departed Chicago bound for Los Angeles. Moments after takeoff, the aircraft’s #1 engine separated from the left wing and flipped up over the top of the aircraft. The ensuing crash killed all 271 passengers and crew onboard, and two on the ground. In the investigation into what remains the deadliest single plane crash on US soil, it was discovered that American Airlines was using a method to change engines on the aircraft that was not approved by McDonnell Douglas, and it was soon discovered that two other US carriers, United and Continental, used similar methods.
This method was to remove the engine and support pylon at the same time, instead of removing the engine first, and then the pylon like Douglas called for. In the case of United, they used a series of hoists to accomplish this task. However, American and Continental used a large forklift to support the engine/pylon assembly during the removal process. It was discovered that eight weeks prior to the crash, the #1 engine on N110AA was changed using this method, and that undue stress was placed on the pylon to wing attach fittings during the process. At a critical time in flight, when full thrust of the engine was applied to these fittings, they finally failed, causing the results witnessed.
Upon investigation, it was revealed that many other American and Continental DC-10s had damage to their mounts, while aircraft from United did not. Since this crash was caught on film, and the footage was shown on TV news broadcasts across the nation, many refused to fly on the DC-10, labeling it an unsafe aircraft and a death trap. It was so bad that American, who had labeled all of the DC-10s with “DC-10 Luxury Liner” monikers on the nose, removed the DC-10 markings, and just called them “Luxury Liners”.
Throughout the next ten years, there would be many more accidents involving the DC-10, however most of them would be the result of crew error, such as the November 28, 1979 sightseeing flight over Antartica by an Air New Zealand DC-10, ZK-NZP. This crash was the result of controlled flight into terrain when the aircraft flew into the side of Mount Erebus, killing all 257 passengers and crew. The next major technical malfunction would bring the DC-10 into the spotlight again, but this time in a positive light.
On July 19th, 1989, United Airlines Flight 232, operated by N1819U, was en route from Denver to Chicago when the #2 engine, located in the tail, suffered a catastrophic uncontained failure over Iowa farmland. I will not go into too much detail about this crash, since it is one of the best known and documented aviation incidents, but a brief synopsis follows: As a result of engine fragments severing all three hydraulic systems, the pilots lost all control of the aircraft, and it was only through the application of differential thrust that they were able to rudimentaly control the aircraft and attempt a landing in Sioux City Iowa.
It was the efforts of Captain Al Haynes, First Officer William Records, Second Officer Dudley Dvorak, and Captain Dennis Finch, that there were any survivors. When one looks at the footage of the crash, it is hard to believe that anyone could have survived, but 185 of the passengers and crew lived.
After the Sioux City crash, the DC-10 has led a relatively quiet life, serving many airlines and cargo haulers safely for decades. After Northwest Airlines retired their last DC-10 in 2007, the type left mainstream commercial service in North America and Europe. However, the type continued to soldier on in southern Asia with Biman Bangladesh. In the following days, over 42 years after the type’s entry into full passenger service, its days will be nearly over, as Biman retires their last DC-10, the second to last airframe built. The type will live on for many more years, however, just not carrying passengers anymore: it will still make money as a freight hauler, mainly with FedEx.