DC-10/MD-11 Control cabling.
Thread Starter
DC-10/MD-11 Control cabling.
Does the DC-10/MD-11 autopilot utilize the cabin floor routed control cables to operate the (tail) control surfaces? Or was it a different system, possibly above the cabin using electrical signals? I would usually look at the manual but I can't find any online in pdf format to fathom the answer to this question, which to fellow oldies/anoraks will know why I am asking.
Does the DC-10/MD-11 autopilot utilize the cabin floor routed control cables to operate the (tail) control surfaces? Or was it a different system, possibly above the cabin using electrical signals? I would usually look at the manual but I can't find any online in pdf format to fathom the answer to this question, which to fellow oldies/anoraks will know why I am asking.
I didn't work on DC-10 but I assume its CWS worked in a similar way. (But no, I don't know why you are asking.)
Does the DC-10/MD-11 autopilot utilize the cabin floor routed control cables to operate the (tail) control surfaces? Or was it a different system, possibly above the cabin using electrical signals? I would usually look at the manual but I can't find any online in pdf format to fathom the answer to this question, which to fellow oldies/anoraks will know why I am asking.
https://en.wikipedia.org/wiki/Turkis...nes_Flight_981
cabin floor
Thread Starter
No idea, why you are asking it like it is a big secret. 5 second search on google:
https://en.wikipedia.org/wiki/Turkis...nes_Flight_981
cabin floor
https://en.wikipedia.org/wiki/Turkis...nes_Flight_981
cabin floor
I am of course aware the cables routed through the cabin floor, hence my question.
There has never been any mention/suggestion that re-engaging and flying through the A/P (after it initially disconnected) might have averted the disaster, but that is what a DC-10 IP wrote he was told back in '74, in case of this decompression happening - control could be maintained through the A/P. I am curious if he was accurate in that statement.
Feedback from the rams to the control column is by the mechanical cables which become primary if LSAS/CWS/AP becomes inoperative.
I have no knowledge of where the AP electrical control signals were physically routed. I am sure that there would have been separation of the 4 channels for damage tolerance but I don't know where each of the cable runs was located.
If researching DC-10 flght controls the MD-10 may be a better basis for comparison than MD-11.
Last edited by EXDAC; 19th Jun 2023 at 23:23.
No secret, just didn't want to clutter the question. I am aware of the Wikipedia article (having initially started the article back in '03'ish) - I am also familiar with the entire accident report and all the published books and material as well as contact with some of the authors.
I am of course aware the cables routed through the cabin floor, hence my question.
There has never been any mention/suggestion that re-engaging and flying through the A/P (after it initially disconnected) might have averted the disaster, but that is what a DC-10 IP wrote he was told back in '74, in case of this decompression happening - control could be maintained through the A/P. I am curious if he was accurate in that statement.
Very interesting, so I assume the cables were not employed if the A/P was engaged? And the control wiring could have run above the cabin.
I am of course aware the cables routed through the cabin floor, hence my question.
There has never been any mention/suggestion that re-engaging and flying through the A/P (after it initially disconnected) might have averted the disaster, but that is what a DC-10 IP wrote he was told back in '74, in case of this decompression happening - control could be maintained through the A/P. I am curious if he was accurate in that statement.
Very interesting, so I assume the cables were not employed if the A/P was engaged? And the control wiring could have run above the cabin.
I would expect DC-10 to be similar architecture except that the two MD-11 digital FCC are replaced by analog pitch and roll computers.
Last edited by EXDAC; 20th Jun 2023 at 01:56.
For MD-11 elevator hydraulic actuators are in the horizontal stab. Control is divided between the two flight control computers with FCC-1 driving right outboard and left inboard and FCC-2 driving right inboard and left outboard elevators. FCC control input drives the actuator mod pistons and feedback of mod and ram piston positions is provided electrically to the FCC.
I would expect DC-10 to be similar architecture except that the two MD-11 digital FCC are replaced by analog pitch and roll computers.
I would expect DC-10 to be similar architecture except that the two MD-11 digital FCC are replaced by analog pitch and roll computers.
Thread Starter
Some good information on DC-10 here - https://tinyurl.com/39kjf52s
There is an "Automatic Flight Guidance System block diagram" included in the doc "Douglas DC-10F familiarization" (linked in third post to that thread).
There is an "Automatic Flight Guidance System block diagram" included in the doc "Douglas DC-10F familiarization" (linked in third post to that thread).
Some good information on DC-10 here - https://tinyurl.com/39kjf52s
Thread Starter
If you really want detail of the mechanical elevator control system download IPC_ATA-25-34.pdf which is linked later in the same thread. It's a searchable PDF and "ELEVATOR HYDRAULIC ACTUATION" shows the elevator hydraulic actuators in detail. A search for "Elevator" finds all the parts between the control column and the actuators. I have not yet found similar detail for the flight guidance system actuator interface. It should be in ATA chapter 22.
