No secret. Common knowledge. Read the OP. Again. Read the Wikipedia on DC-10... In a nutshell, DC-10 doors opened OUTWARD (relying only on the latches to stay shut under pressure), instead of IN (so as pressure inside built they sealed more tightly). And it was possible in some instances to get a false reading on the panel showing the doors shut, when they were not actually latched and locked.
He didn't talk about it much other than he thought his design was good - mind you, I was only 14 at the time. Joe, my dad's mate at American refused to fly the 10 as he felt, among other things that the main landing gear was insufficient for the bulk of the aircraft - not enought wheels. Mind you, he wanted the 707 to keep going forever, that was his perfect plane. John
Thanks for sharing - the video seems pretty well researched and balanced.. We had friends who died in the Paris disaster. A young married couple who couldn't conceive. Traveling to pick up their newly adopted baby daughter. Coincidentally we had made friends with them as co-passengers on a JFK-OSL flight a few years prior, they lived in our city. As mentioned in the video - In the Chicago disaster, the cause was found to be metal fatigue in one of the engine pylons. Basically one of the wing engines fell off just after lift off. That accident seems to be the one that sticks in most people's memory of the DC-10. In the 80's I flew on a good number of SAS DC-10's JFK-OSL with no issues. Some of the SAS flights would fly the return OSL-JFK leg with a bulkhead halfway down the cabin. Behind it was stored 20 tons of fresh Norwegian salmon headed to US restaurants... The one L-1011 experience I had I will absolutely never forget - flew very early on in it's career, mid-70s and must've been a very new aircraft.. I'd venture to say it was the most luxurious flight I think I've ever experienced... quiet, silky smooth, and the finishes and interior were perfect. Eastern Airlines, and their cabin service was exemplary too. Another old aircraft that impressed was the Boeing 727.. talk about acceleration. That aircraft had a lot of reserve power. I understand it was also one of the last airliners with a flight engineer in the cockpit. Cheers, - Art
As do the lower lobe cargo doors on all wide-body aircraft, with the exception of the bulk cargo doors which are much smaller. Note: the original design on the 747 may have had inward opening doors but that was quickly changed when they understood the amount of cargo volume lost. In addition, all main deck cargo doors, which are much larger than lower lobe doors, are also outward opening and rely on latches to stay shut. Several notable cargo door failures, including United Flt 811 (Boeing 747) in 1989, resulted in changes to the latching/locking/indication requirements for outward opening doors. In addition to added cockpit indications, independently for latching and locking, there are visual indicators on the door for each latch visible by ground personnel after door closing.
This is one reason I love F-Chat. I flew that TWA JFK-SEA and return flight a bunch of times in mid 80's. Big 1011. I had a first class seat but sometimes would go back to coach where one could find all 5 middle section seats vacant. I would take a blanket and couple of pillows back there and snooze away (no lie-flat front cabin seats in those days). The L-1011 reminded me of flying in a Mack Truck with wings. I always hated the DC-10.
Art. the DC-10 strut failure was due to a cracked and deformed fitting at the aft end of the upper rib next to the wing lower surface. The fitting was damaged in the improper removal of the entire engine/strut combination as a single unit when it was supposed to have had the engine removed and then the strut removed. The forklift operator applied a damaging load on the aft fitting that later failed under a full engine thrust condition during the take off at Chicago. Then a chain reaction of failures occurred that failed the forward bulkhead ("tombstone fitting") to which the engine was mounted and the whole thing rotated about the front spar and severed all the hydraulics in the leading edge that allowed the slats to retract in the left wing. The airplane was put into an uncontrollable roll.
It was not fatigue, really... it was due to improper maintenance procedures by AA to save time. (other airlines did it also). Douglas had specific instructions that were not followed. The engine attachment/pylon mounting structure was damaged in the process causing the engine to rotate up over the top of the wing and break free on T/O. You're right, this is the one that sticks in everyone's mind. It was in the US, tons of photographic series of second by second history of the crash. I knew an AA stewardess that was supposed to be on AA flight 191 when another asked her to trade flights with her... saved her life.
If you want to see how the DC-10 engine strut was designed you can go to Google and type in "DC-10 engine strut design" and you can see what a poor design it is. Thrust loads are reacted in closely coupled tight little bunch of fittings and a short "thrust link"under the wing front spar. The forward bulkhead is set up take a bending force if there is a failure and that is what it did. The aft clevis fitting that failed initially is 90 Deg to thrust and doesn't seem to do any more than to keep the strut aligned. The Boeing 747 strut has two huge thrust links , all aligned with the thrust. All of the forged fittings are tied into the wing ribs that are aligned to the thrust loads . The torque rib in the strut is mounted to heavy forgings that are fastened to others inside the wing that are fastened to the spars and ribs. Take a look.
Ha, did the same thing on 747s back in the day! It was a lot better laying down in couch than sitting upright in first.
If the pilots were aware that the left slats had retracted, I think they would have been able to fly out of it by continuing to accelerate straight ahead and retracting the right wing slats. They followed the accepted engine-out procedures, which resulted in the left wing stalling and the resultant fatal roll. I believe the 747 and L-1011 both had mechanical downlocks for the slats, whereas Douglas simply kept them down by hydraulic pressure. Is that correct?
I read (somewhere) that this procedure has been taught in the simulator routinely since... retract right slats, power up... On the sim, it usually works, can gain altitude.
I read that the pilot did everything exactly correct as trained and by what was in the manual. I doubt that he had the time to retract the right hand slats and level out. It reminds me of the Martin B-26 when an engine fails. Few pilots had the training or discipline to cut power in the good engine and fly the airplane in. Thirty percent of the lift on a B-26 was produced by air flow from the prop, prop wash. When that quit , the airplane went into a roll.
Bob, I read that the pilot did not know the slats had retracted, or he might have done differently and saved the airplane. Apparently the engine-out procedure called for reducing speed, and when he did that, the left wing stalled.
Thanks, Jim. I seem to remember that when the airplane started the roll he applied right rudder, right aileron and made throttle adjustments. Never mind what coulda been and shoulda been, it was a bad day for everyone.
Apparently, the left engine supplied electrical power to the cockpit, which would have included a warning of unintended slat retraction, as well as a stick-shaker for the initiating stall. Without those warnings, the pilot "ran out of information and altitude simultaneously". Continental and United also used the same incorrect engine-removal procedure, and some of their 10s also had damaged engine mounts when subsequently inspected.
Bob- The P-38 also called for reducing power in the event of an engine loss. Counterintuitive, but...
If I remember correctly, the slats on a Boeing are shaft driven. I'm going to dig around but I think that they are deployed by a torque shaft.
The 747 slats are actuated by a shaft from wing tip to wing tip powered by an air turbine. No hydraulics involved.
T- The B-26 had counterrotating props, too. The Brits were the only ones that wanted twins without counter-rotating props, as far as I know. One reason the P-322 was so worthless, among others.
I should have remembered the loud noise from the compressed air turbine when they test the slats on the assembly line. The TE flaps are also shaft driven and actuated by Acme screw shafts.
The TE flap drives on all Boeing aircraft are pretty loud and can generally be heard throughout the cabin when the pilot lowers them for takeoff - reassuring if you can't physically see the flaps. The LE drives are much quieter inside.
