JAM747
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First Plane To Have Auto Pilot And Auto Land?

Thu May 12, 2005 5:24 am

Which was the first aircraft to have autopilot or auto land? Was it a commercial plane, if not which was the first commercial plane to have these features? In layman term how do they work? Thanks
 
AirWillie6475
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RE: First Plane To Have Auto Pilot And Auto Land?

Thu May 12, 2005 5:39 am

The first plane to autoland was a Trident in the 1960s.
 
OzLAME
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RE: First Plane To Have Auto Pilot And Auto Land?

Thu May 12, 2005 6:10 am

Autopilot described in laymans terms? An error signal is produced, that signal is sent to the autopilot servo which moves the control surface to oppose the error signal. The servo sends a signal back to the a/p and when the error signal and feedback signal cancel each other out everything goes back to waiting for the next error signal. This is a very simplified explanation.

Autopilots have been around at least since the 1930s; DC-3s had a Sperry system fitted that was controlled by the attitude indicator a.k.a. the bank-climb box, and directional gyro. These controlled hydraulic servos via cable-driven control valves. The cables were moved by the instruments themselves, via small wheels on the back of the instruments that mated to wheels mounted behind the centre instrument panel using a clutch arrangement.

I've never worked on an aircraft with Autoland, but as I understand it the aircraft has essentially three completely separate autopilot computers and all have to agree with each other for successful engagement of the autopilot. The crew have to be rated and current as well.
Monty Python's Flying Circus has nothing to do with aviation, except perhaps for Management personnel.
 
JAM747
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RE: First Plane To Have Auto Pilot And Auto Land?

Thu May 12, 2005 8:01 am

Quoting OzLAME (Reply 2):
Autopilot described in laymans terms? An error signal is produced, that signal is sent to the autopilot servo which moves the control surface to oppose the error signal. The servo sends a signal back to the a/p and when the error signal and feedback signal cancel each other out everything goes back to waiting for the next error signal. This is a very simplified explanation.

Very well said and understood, thank you, it makes sense.
 
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Starlionblue
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RE: First Plane To Have Auto Pilot And Auto Land?

Thu May 12, 2005 10:24 am

OzLame covered it well. I would add that there are two signals sent out from the ground. One is called the localizer and gives a baseline for horizontal deviation (left or right of runway centerline). The other is called the glideslope and gives a baseline for vertical deviation (above or below the glidepath).
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
411A
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RE: First Plane To Have Auto Pilot And Auto Land?

Thu May 12, 2005 11:16 am

The HS.121 Trident was indeed the first civil type to be certificated with automatic approach/land (autoland), however the very first aircraft to be so equipped (and certificated) was the Shorts SC.3 Belfast, utilizing the same Smiths Triplex autoland system.

In addition, three autopilot channels are not necessarily required for an automatic approach/land to be accomplished.
For example, the B747 can use only two...as can the Lockheed TriStar.
However, for CAT III ops, three are required....all four on the TriStar.
 
DeskPilot
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RE: First Plane To Have Auto Pilot And Auto Land?

Thu May 12, 2005 12:13 pm

Quoting 411A (Reply 5):
was the Shorts SC.3 Belfast

I think I read a quote once about the Belfast's failure to meet it's range target. Something about "it could carry a full load across the English Channel, or a packet of crisps its full range".
By the way, is there anyone on board who knows how to fly a plane?
 
AvionicMech
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RE: First Plane To Have Auto Pilot And Auto Land?

Thu May 12, 2005 12:14 pm

Quoting 411A (Reply 5):
For example, the B747 can use only two...as can the Lockheed TriStar.
However, for CAT III ops, three are required....all four on the TriStar.

I think only 3 channels are required for CAT IIIB, as our 737-800's only have FCC A and B and they are CAT IIIA certified.
 
jwenting
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RE: First Plane To Have Auto Pilot And Auto Land?

Thu May 12, 2005 1:16 pm

Quoting DeskPilot (Reply 6):
I think I read a quote once about the Belfast's failure to meet it's range target. Something about "it could carry a full load across the English Channel, or a packet of crisps its full range".

But it could do an autoland, making everything else secondary Big grin
I wish I were flying
 
OzLAME
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RE: First Plane To Have Auto Pilot And Auto Land?

Thu May 12, 2005 4:21 pm

Quoting Starlionblue (Reply 4):
there are two signals sent out from the ground. One is the localizer. The other is the glideslope

Autoland also needs the aircraft's radio altimeter to determine the correct height at which to command the flare for touchdown.

Quoting 411A (Reply 5):
However, for CAT III ops, three are required....all four on the TriStar.

Yes, CAT II is less stringent because in CAT II ops the pilot is still actually landing the aircraft; only in CAT III does the autopilot perform the landing. So (if I remember my autopilot theory, and please correct me if I am wrong) for CAT III, automatic pilot-performed landings, you must have:

Crew rated for CAT III and current (i.e. recently performed CAT III landings) as well; a valid Localiser signal; a valid Glideslope signal; a valid Radio Altimeter signal; autothrottles and a minimum of three autopilot computers/channels, all verifying with each other that their command signals etc. are the same. I believe the runway itself must also be rated for CAT III ops.

It's a long way from the Sperry system in the DC-3 and Lockheed Super Electra, which couldn't do much more than keep the aircraft flying straight and level.
Monty Python's Flying Circus has nothing to do with aviation, except perhaps for Management personnel.
 
saintsman
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RE: First Plane To Have Auto Pilot And Auto Land?

Thu May 12, 2005 6:07 pm

There was an RAF Tristar that did an autoland at Brize Norton in the Mid 80s. Unfortunately autoland wasn't fitted. When it hit the ground it bounced 60ft into the air, forcing a go-around and losing 6 tons of fuel in the circuit before landing safely.

Quoting OzLAME (Reply 2):
Autopilot described in laymans terms? An error signal is produced, that signal is sent to the autopilot servo which moves the control surface to oppose the error signal.

Yes that is correct but for a layman an 'error signal' may not mean too much. When the autopilot is set, the pilot generally wants to fly straight and level (It can also do many more things). Sensors, like gyros, accellerometers, pressure transducers etc detect any variation in the aircraft from what the autopilot was set to. These sensors produce the 'error signal' (the difference between what the sensors are reading and what was originally set) which is fed through the autopilot to the servos. The servos move the flying controls until the aircraft regains its original setting, meaning that the error signal is now zero.
 
schooner
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RE: First Plane To Have Auto Pilot And Auto Land?

Thu May 12, 2005 6:13 pm

Ummm, CAT II is still an auto land as far as I know.

Cheers.

[Edited 2005-05-12 11:20:39]
Untouched and Alive
 
Glom
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RE: First Plane To Have Auto Pilot And Auto Land?

Thu May 12, 2005 9:22 pm

Is autoland used for CATII/III only or can it be used during CAT I? Would the system need the signal quality that can only be achieved during CAT II/III operations?
 
schooner
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RE: First Plane To Have Auto Pilot And Auto Land?

Fri May 13, 2005 7:04 am

Its more the other way round, the "CAT" of a landing refers to the meterological conditions needed to continue the approach (ie, CAT I 200`DH, 550m RVR, CAT II 75`DH, 300m, CAT IIIA 50` DH, 200m RVR and CAT IIIB 0`DH and 200m RVR*). CAT II/III ops are autolands and CAT I is a manual landing. CAT II & IIIA with a decision height and CAT IIIB no decision height. Autolands are carried out when Low Vis Ops are in force (LVPs). The ILS used is the same but when LVPs are in force there is extra protection for the ILS beam (ie, aircraft hold short further away from the runway) so there is less deviation on the beam, meaning the autopilot can follow the beam all the way to the runway.....in a nut-shell.

Cheers.


*rough ball park figures, can`t be arsed to dig out the exact ones...they can vary anyway!
Untouched and Alive
 
411A
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RE: First Plane To Have Auto Pilot And Auto Land?

Fri May 13, 2005 11:08 am

A fair bit of mis-information here, so will try to elaborate further.

Most modern Boeing aircraft are equipped with triplex autopilots, for autoland operations, utilizing CAT III minima.
However, the actual automatic approach land (autoland) maneuver does not require any specific minimum visibility or weather conditions, it is simply that...an automatic landing.
It can be done in CAVOK conditions at any time, so long as the airfield and aircraft are properly equipped.

The TriStar has two dual-channel autopilots (quadriplex system) and differs from the Boeing triplex system mainly as to the number of autopilot channels.

The RAF TriStar that was referred to previously landing at BZZ, was indeed equipped with the standard fit Lockheed autopilot(s) system, fully capable of automatic approach/land operations, however, the PIC decided (for reasons unknown) to engage the autopilots well inside the final approach fix, and the autopliots did not have enough time to achieve 'approach/land track' which occurs 25 seconds after glidepath intercept, or 1500 agl, whichever is LATER.

Therefore it landed VERY hard...and the RAF pilot was returned to desk duty.
He was, as I recall, a sq. commander.

The Shorts SC.3 Belfast was indeed underpowered (in spite of having 5000shp Tyne engines, and was also slower than expected, in operational service.
The crews referred to it as the ...Belslow.

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