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Tristar L-1011 FMS & Autopilot

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Tristar L-1011 FMS & Autopilot

Old 15th May 2009, 06:52
  #41 (permalink)  
 
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TriStar,

Simply magnificent,

When I was a kid I used fly a lot on the AirLanka TriStars between Colombo and Frankfurt.
They were such amazing machines, way ahead of their time and one of the reasons I wanted to start flying.
Probably 411A would have been flying them at that time.
The one regret I have is never having gotten the chance to fly one of them, would have been nice to see stuff like DLC etc. in action.
Instead I ended up being in the playstation generation only flying glasscockpit ever since. But there are quite a few guys who would have loved to fly the old girl, especially when we talk to people who have flown them into places like Kai Tak with a little smile on their faces remembering an era long long gone.

The TriStar was Lockheed's masterpiece of civil aviation setting the benchmark for others to follow.
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Old 15th May 2009, 07:22
  #42 (permalink)  
 
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The TriStar dash 500 was the best airliner of its time, only seconded by the......Concorde !
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Old 15th May 2009, 14:27
  #43 (permalink)  
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Auto turubulance & gust stabilization

When engaged the AP also provides for automatic stabilization for turubulance & gusts (i.e. attitude regulation aided by the IRS) but once disengaged and the plane is being maually flown this stabilisation aid lost.

On a manaully flown gusty approach ( or after AP disengage beyond DH ) what automatic satbilization support was available?
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Old 15th May 2009, 15:49
  #44 (permalink)  
 
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On a manaully flown gusty approach ( or after AP disengage beyond DH ) what automatic satbilization support was available?
Yaw damping and turn co-ordination, provided by the SAS system.
This system also provides two other functions....runway alignment and rollout, however for autolands only.
In addition, DLC is available all the way to touchdown.
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Old 15th May 2009, 16:04
  #45 (permalink)  
 
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Miss you

The airplane that ill never forgget. A true lady and yet a gentleman. Miss it so very much

The last time ive pulled the reversers on the RBs
YouTube - My last L1011 landing
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Old 15th May 2009, 18:51
  #46 (permalink)  
 
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..will have no difficulty forgetting it.....
As you have no doubt personally demonstrated...continuously.
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Old 15th May 2009, 22:23
  #47 (permalink)  
 
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On the other hand I, like a great many other engineers that had the misfortune to work on the old hangar queen will have no difficulty forgetting it.....
I had the good fortune of working on the TriStar for over 30 years and found the any engineer that did like working on her, did know how to work on her.
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Old 17th May 2009, 11:13
  #48 (permalink)  
 
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A colleague of mine at TAP misses the TriStar and tells me that even the maintenance manuals are so well built and intuitive, it would actually teach you how to work on the aircraft!

Would you agree to this?
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Old 17th May 2009, 13:02
  #49 (permalink)  
 
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General fault issues would be recorded in the tech log using the FIRM manual.
Usually a code number only, however oftentimes some airlines required the written text as well, for clarification.
SaudiArabian was one of the latter.
This FIRM code would also be communicated to the destination station when in-range (usually about 100 miles) and ground maintenance personnel would then refer to their manual, to assertain the correct rectification, using the FIRM code.

Many times I would taxi up to the parking stand, and there would be the ground engineer, parked in his vehicle, with the required avionics units to be replaced.
Oftentimes the job would be completed in twenty minutes.
Some airlines casually dismissed the FIRM method as being 'obtuse' however in my experience it worked to a 'T'...at least from this pilots perspective.
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Old 17th May 2009, 19:59
  #50 (permalink)  
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Dlc & Sas

... reading some of these messages it appears implied that DLC was unique to the TriStar, what about other wide bodies? The 747 has a similar array of speed brakes and spoilers.

411A,
does that mean that SAS and DLC ( & YD) remained active (or could remain if so commanded) after AP was disconnected as for instance during a manual approach?
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Old 18th May 2009, 01:26
  #51 (permalink)  
 
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Seems I remember a problem with the "S-ducting" that routed air to the center engine. There were some fiberglass fittings that could break away and find themselves going into the engine? Caused some inflight shutdowns?
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Old 18th May 2009, 02:44
  #52 (permalink)  
 
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411A,
does that mean that SAS and DLC ( & YD) remained active (or could remain if so commanded) after AP was disconnected as for instance during a manual approach?

Yes, SAS (yaw damping and turn co-ordination) was a full time operation, either manual or auto flight.
DLC was also full time, either manual or autoflight, and was initiated when the flap handle passed the 30 degree position.

... reading some of these messages it appears implied that DLC was unique to the TriStar
Correct, unique to the TriStar amongst civil jet transports.
Also unique was the all moving tailplane for pitch control.

A delight to fly.
Having said this, these airplanes are definitely getting old, and consume considerable man-hours to keep 'em going.
Having Lockheed and RR factory trained folks certainly helps.
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Old 18th May 2009, 02:45
  #53 (permalink)  
 
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I think it's time to move on
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Old 18th May 2009, 10:09
  #54 (permalink)  
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Thanks 411A

Interesting that the SAS was full time. Obviously control system design stopped it flighting pilot inputs.

Did these unique TriStar features make it difficult for crews to move to say a DC-10 or 747 interchangably? As you'll know BA operated all three wide bodies for a while after it absorbed BCal so multi-type certified pilots were probably desirable.

Regardig the variable incidence tail plane, the 727 and other T-tails moved the whole thing during rotation ( & for trimming but stand to be corrected) , but not sure if only the elevators were used for pitch control in other phases of flight. I suppose that when large moments are required the whole stabiliser moves on most modern jets 747 and DC1-0 included.
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Old 18th May 2009, 12:16
  #55 (permalink)  
 
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727 and other T-tails moved the whole thing during rotation
727 was pretty straight fwd, stab was only for trimming.
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Old 18th May 2009, 12:59
  #56 (permalink)  
 
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does that mean that SAS and DLC ( & YD) remained active (or could remain if so commanded) after AP was disconnected as for instance during a manual approach?
DLC was also full time, either manual or autoflight, and was initiated when the flap handle passed the 30 degree position.
411A is right but there is one more requirement is needed: DLC is active anytime aircraft was in in the landing configuration: 2 of the 3 engines are less than full power and the flaps greater than 30 degrees.

The DLC system can be shut off by unlatching the DLC/AUTO SPOILER switch light on the pilots overhead panel. However, if the switch was unlatched the pilot would have to manualy deploy the spoilers, if required, after touchdown.


Seems I remember a problem with the "S-ducting" that routed air to the center engine. There were some fiberglass fittings that could break away and find themselves going into the engine? Caused some inflight shutdowns?
The S-Duct was made entirely of aluminum (2024-T3 and 7075-T6) no fiberglass. However there was acoustic material on the engine (just if front of the fan) this would disbond at times and be ingested by the engine. This acustic material was on all RB-211's not just the TriStars No. 2 engine.
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Old 18th May 2009, 13:08
  #57 (permalink)  
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...The DLC system can be shut off by unlatching the DLC/AUTO SPOILER switch light ...

What about SAS, were means provided to switch it off should it be required?(although it would normally be active)
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Old 18th May 2009, 13:27
  #58 (permalink)  
 
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What about SAS, were means provided to switch it off should it be required?(although it would normally be active)
Yes, both channels could be disabled by unlatching the appropriate switchlights on the overhead panel.

727 was pretty straight fwd, stab was only for trimming.
Likewise for the DC10 and B747
The L1011 is unique with it's all-moving tailplane for pitch control on civil jet transport aircraft.
Also note that the L1011 has four hydraulic systems (same for 747) but unlike other first generation wide-body jet transports, which had only three.
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Old 18th May 2009, 13:55
  #59 (permalink)  
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HS Trident all-flying tailplane

An interesting variation on a theme is that the HS Trident, unlike its 727 look-alike, used the whole tailplane for pitch control I have seen pics of it fully deployed at rotation. Ditto for the VC-10 .

So in this sense tailplane use was similar to that of the TriStar.
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Old 18th May 2009, 14:32
  #60 (permalink)  
 
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**So in this sense tailplane use was similar to that of the TriStar.**

Don't think so, however those that have flown these types can comment.

Keep in mind that with the L1011, when the pilot pulls back on the pole (or, pushes forward) the entire horizontal tailplane moves.
The entire tailplane also moves with trim input.
The elevators are not directly controlled by the pilot...IE: they are mechanically linked to the stabilizer.

AFAIK, this arrangement is unique amongst western civil jet transport aircraft.

DLC is active anytime aircraft was in in the landing configuration: 2 of the 3 engines are less than full power and the flaps greater than 30 degrees.
Certainly correct.
Note.
If a go-around is desired, the first action of the pilot is to apply go-around thrust.
By doing so, DLC is automatically disabled (active spoilers stowed), prior to moving the flaps to the 22 degree position...which would then be the next pilot action.

Full time automation...a TriStar exclusive at the time.
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