Planes of The Past 6- McDonnell Douglas DC-10/MD-10

Hey there, welcome back to the long overdue 6th part to PoTP! Today I will be covering the DC-10, in light of it coming to the game soon.

Enjoy!

DC-10

Specifications taken from Wikipedia:
DC-10-10 DC-10-15 DC-10-30 DC-10-4
Cockpit crew: Three
Seating: 380 (maximum, exit limit)
285 (2-class)
255 (3-class)
Cargo (freighter variant) 22 LD7 pallets 23 LD7 pallets
Fuselage length 170 ft 6 in (51.97 m)
Height 58 ft 1 in (17.7 m)
Wingspan 155 ft 4 in (47.34 m) 165 ft 4 in (50.4 m)
Fuselage width 19 ft 9 in (6.02 m)
Fuselage height 19 ft 9 in (6.02 m)
Max interior width 18 ft 2 in (5.54 m)
Operating empty weight 240,171 lb (108,940 kg) 266,191 lb (120,742 kg) 270,213 lb (122,567 kg)
Maximum take-off weight 430,000 lb (195,045 kg) 455,000 lb (206,385 kg) 572,000 lb (259,459 kg) 555,000 lb (251,701 kg)
Cruise speed, typical Mach 0.82
(564 mph, 908 km/h, 490 kt)
Cruise speed, maximum Mach 0.88
(610 mph, 982 km/h, 530 kt)
Maximum range, loaded 3,800 miles (6,116 km) 4,350 mi (7,000 km) 6,600 mi (10,622 km) 5,750 mi (9,254 km)
Fuel capacity, maximum 21,700 U.S. gal (82,134 L) 26,647 U.S. gal (100,859 L) 36,650 U.S. gal (138,720 L) 36,650 U.S. gal (138,720 L)
Takeoff run on MTOW 8,612 ft (2,625 m) 7,257 ft (2,212 m) 9,341 ft (2,847 m) 9,242 ft (2,817 m)
Service ceiling 42,000 ft (12,802 m)
Engine model (x 3) GE CF6-6D GE CF6-50C2F GE CF6-50C PW JT9D-59A
Engine thrust (x 3) 40,000 lbf (177.9 kN) 46,500 lbf (206.8 kN) 51,000 lbf (226.9 kN) 53,000 lbf (235.8 kN)

The McDonnell Douglas DC-10 was meant as a response to Lockheed’s L-1011 trijet. Both planes came from a 1966 American Airlines requirement for a widebody jet with the range of the 747 but with the ability to use the large majority of runways at the time, considering that the 747 needed major modifications to existing airports before it could service it. It also needed much longer runways, which AA did not have at all the airports it wanted to serve. Therefore, the plane became a trijet to meet this requirement.

First flying on August 29 1970, the DC-10-10 was launched with orders from AA and United. It got its type certificate on July 29, 1971 before entering service with AA on August 5th on the same year. Unlike the L-1011, it was powered by General Electric CF6 engines, meaning it did not have to suffer through the problems that the RB211 on the Lockheed had to face.


The interesting about the DC-10 was that instead of having the engine in the fuselage like the Boeing 727 and the L-1011 connected through an S-duct, MD opted for a “banjo frame” design, where the engine was mounted on top of the tail. This meant that additional passengers could be carried as there was now more space inside the plane. This was an advantage over the L-1011 with the S-duct as it could have international capabilities, not realised with the L-1011 until the -500 version, which was too little too late.

The DC-10-30 was the first version of the DC-10 specially built for international operations. It had a extended range of 6220 miles compared to the 3800 miles of the -10. The series 20 model was later changed to a -40 at the request of Northwest.

clip_image042
The intake of an Iberia DC-10-30. Note the dark lines marking out the banjo frames and the shape of the inlet- other DC-10s look slightly different…
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This is the intake from a NW DC-10-40. So as it turns out, even the DC-10s had the bulged banjo frames!

I won’t really be touching much on the Death Cruiser part of the name, but I do feel that this needs to be cleared up. Even though statistically the DC-10 is one of the most dangerous passenger airliners built, I do not feel that it can be considered “unsafe” in any way. Granted, the L-1011 was a much better aircraft, but the DC-10 cannot be totally faulted. Here’s why.

Cargo Door Latch
In essence, the cargo door on the DC-10 was built to extend outwards instead of inwards. This would mean more space to carry cargo as the space directly behind the door could be used, unlike planes with plug type doors. However, this meant that if the latch was incorrectly fitted, the door was at higher risk of being blown out. As per a design standpoint, this would not be a problem as long as the door was closed properly every single time. The only problem with that was that it wasn’t, leading to AA96, then eventually Turkish 981 with the loss of all on board. Both accidents were caused by ground crew not fully locking the pins due to the design making them looked like they were safely latched even though they weren’t. After a mandated FAA fix, the problems were solved.

Engines Blowing Themselves to Bits and other turbofan related maladies
Due to the lack of a manual cable backup, in the occasion that all the hydraulics were lost, it would have been impossible to control the plane. This was deemed as highly unlikely, therefore none was provided.

On the 19th of July 1989, United 232 suffered a loss of pressure in all 3 hydraulic systems after a fan disk failure caused shrapnel to cut through the lines, rendering the plane uncontrollable. Due to the skill of the flight crew who managed to bring the plane to a crash landing on the runway, 185 of the 296 people on board were saved from near certain death. The fix for this was to have fuses on the hydraulic systems so that in case of a loss of pressure, the plane would retain the hydraulics and remain controllable.

Further back in 1979 however, AA flight 191 crashed after the number 1 engine separated from the wing during takeoff. This caused the hydraulics to sever and the leading edge slats lost pressure as a result. This would not have been a problem, but the crew’s training meant that they needed to bring the speed down to V2. This, coupled with the loss of the slats stalled the wing, causing the plane to flip over and crash. It was unfortunate that the lines on the left wing were also controlling the captain’s stick shaker which the co-pilot did not have. This lack of warning along with asymmetrical lift conditions led to the crash of the plane.

In conclusion, if many of these incidents had happened on a L-1011, there was the possibility that it would never have happened. However, this can be attributed to Lockheed over-designing their planes rather than Douglas being too careless. Could the plane have been built better? Yes. Would the plane have been as successful if it had taken longer to implement these? Possibly not, but nobody knows, so stop harping over it!

MD-10
The lesser known DC-10 variant, this is basically a DC-10 with the newer MD-11 cockpit and wiring as well as a common type rating between the two aircraft.


The older DC-10 cockpit with the old steam gauges.

The newer cockpit taken from the MD-11. Note the MD-10 designation on the yoke.

Even though it shared the cockpit and interchangeable type rating, there is apparently a huge difference in the way both planes handle, due to the smaller horizontal stabiliser on the MD-11, but that’s a story for another PoTP!

Even though the DC-10 is a very old aircraft, many are still flying today as MD-10s. The most well known would probably be FedEx, who has a large fleet of MD-10s and MD-11s. Also notable is the Orbis DC-10, which serves as a hospital for use in third world countries where the proper equipment may not be available. It has been retired as of 2016 and replaced with a newer former FedEx MD-10.

867

Sorry if this edition is shorter than normal, but I’ll make up for it with an extra long one next week!

Have a great week ahead, and see you in Part 7!

26 Likes

Wow! Very informative :) It’s sad the DC-10 didn’t have cable wires in case the Hydraulics failed, but at least they put something to help the hydraulics stay and keep the plane controllable. I didn’t think the DC-10, could use the MD-11 cockpit, and be called the MD-11. This is a great topic detailing about the DC-10 and MD-10 :)

@Iggydang… MaxSez: “Well Done” Your efforts and research produced a professional outcome worth publication. Look forward to the next chapter in your epic. (Bookmarked)

(The “Death Cruiser”. Well described! All “Tri-Holers” carry the 10’s stigma. I rode one once when I was young and foolish. I’ve learned since to check equipment & safety records before I buy a ticket. I don’t fly no stinking T-Tail
or Tri-Holer!)

3 Likes

In my opinion, the DC-10 ruined the three engine design for aviation. There were quite a few initial design flaws that McDonnell-Douglas corrected too late, and at the cost of many lives. The L-10, 727, and MD-11 were great tri-holers.

3 Likes

And all 3 hydraulic systems were routes next to each other through the vertical stabiliser. This meant when the engine went, it would shear all 3, a fatal design error on McDonnell Douglas’ side. The FAA now mandates they are not routes so close I believe


Really fantastic read, I really enjoyed it :)

In their defence, even cable backups in a plane that big would have added lots of extra weight for a scenario deemed unlikely due to triple redundancy. It was really unfortunate that the fan blade managed to take out all 3 lines, but the fact that they did not have fuses to remedy this was unforgivable as Lockheed had already done it, and with an extra line (I’m a big L-1011 fan by the way, in case the slight DC-10 bashing wasn’t obvious enough)

Thanks so much Max, your compliments are always appreciated!

It could have been said that the whole 3 engine concept was flawed from the beginning of ETOPS. With the high reliability of modern engines, the whole “4 engines for redundancy” argument becomes flawed. Granted, for planes like the VC-25A where staying in the air at all costs is top priority, then 4 engines remains king as in-air refuelling is an option.

The only really successful commercial 3 engined plane was the 727, and even that was due to the amazing wing allowing it to service shorter runways while still having a high cruise speed. It was not totally flawless though, it ended up in a deep stall due to the T-tail configuration during flight tests, only saved by the fact that some control remained and it could be rocked side to side until it regained control.

400px-UA232_damage
Correct. This FAA document from the UA232 report shows all the hydraulics and how they were damaged from the explosion.

In fact, if you have time and want to find out more about the crash, I recommend looking at the final report here

As far as I know the only action taken after that was to install fuses in the Number 3 system, in accordance with AD-90-13-07

In fact, the exploding engine concept was thought of as far back as 1982.

On March 9, 1988, the FAA issued AC 20-128, in part as the result of a Safety Board recommendation made in 1982. The AC provides for a method of compliance with FARs that require design precautions to be taken to minimize the hazards to an airplane in the event of an uncontained engine or auxiliary power unit failure. The AC defines dispersion angles for fragments that may be released during a fan blade or rotor failure. These angles define impact areas relative to the engine installation based on recorded observations of the results of failures both in service and in tests. The AC also provides a listing of design considerations to minimize damage to critical structural elements and systems in the airplane, and defines the fragment energy levels that can be expected from the failure of a fan blade or predicted pieces of a rotor.

This concept was however proved inadequate later on in 1989, as seen above.

4 Likes

The Newer Cockpit looks like the 737 Cockpit

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