Jump to content
Sign in to follow this  
Mathijs Kok

Question of the day <----------------------

Recommended Posts

Aiorcraft can,t take off automatically,bacause there is nothing to guide it down the runway,on landing,the aircraft uses the vor/ils,and marker beacons in the autoplilot in order for it to land by itself.

Share this post


Link to post
Share on other sites

I think you got a few very good points. Yet the question was WHY is there no practical need for it?

The fact low vis landings can not be made manually is for sure a reason it was needed for landings.

Ok so once the aircraft is in the air it needs to get on the ground eventualy. So in case of poor weather that would be the practical need for an autoland capability. The reason why automatic take off capability is not needed could be that when you have RVR below minima for a safe take off, you are at that time most probably safely parked on the ground with the parking brake set and engines off. So you just wait for RVR to improve with a somewhat less of an economic impact to the airline. On the other hand planes that are sitting on the ground do not make any profit so I am not realy sure that I am right on this one but that's just a tought that crossed my mind.

flyhigh

Share this post


Link to post
Share on other sites

The Auto Pilot is not capable of operating below 50 ft. Radar Altitude, The Surface Cross Wind Component is something the Auto Pilot cannot factor in, and the Runway Slope is also something the Auto Pilot cannot factor in either. Also in the case of engine failure on take off the Auto Pilot cannot proses an engine failure at take off; be it Fame Out, Bird Strike, Fire, or the Catastrophic Engine Failure Deployment System.

Icing is another factor that can render ANY Auto Pilot useless: Be it Air Foil Icing, Pitot Tube Icing, Prop Icing, or (Again) Engine Flame Out.

And take off gives something for the pilot to do.

And I like to Critique my posts... A lot.

Share this post


Link to post
Share on other sites

Cost....

Why install/maintain a computer system for takeoff when it is not really needed. Boeing and Airbus have toyed with the idea but it does not make sense from a $$ point of view.

Share this post


Link to post
Share on other sites

WELL IF I SHOULD SAY SOMETHING I THINK IT COULD BE BECAUS IF YOU GET BIRDSTRIKE OR SOMETHING ELS THE PLANE CANT HANDEL IT BECAUS IF YOU NORMALY GET BIRDSTRIKE YOU DISENGAGE THE AUTOPILOT BECAUS YOU HAVE TO SHUT THE ENG DOW AND CORECT THE ARICRAFT WHIT RUDDER AND HOW IS THE AIRCRAFT GONA HANDEL THAT BECAUS ANY LOSS OF POWER CAN BE A BIG PROBLEM I KNOW YOU CAN FLY WHIT ONLY 1 ENG BUT WOULD THE AUTOPILOT ACT AS FAST AS AN PILOT DO. AS AUTOPILOT IS ONLY PROGRAMED HARDWARE/SOFTWARE AND IT IS HARD TO PROGRAM SITUATIONS.

Share this post


Link to post
Share on other sites

WELL IF I SHOULD SAY SOMETHING I THINK IT COULD BE BECAUS IF YOU GET BIRDSTRIKE OR SOMETHING ELS THE PLANE CANT HANDEL IT BECAUS IF YOU NORMALY GET BIRDSTRIKE YOU DISENGAGE THE AUTOPILOT BECAUS YOU HAVE TO SHUT THE ENG DOW AND CORECT THE ARICRAFT WHIT RUDDER AND HOW IS THE AIRCRAFT GONA HANDEL THAT BECAUS ANY LOSS OF POWER CAN BE A BIG PROBLEM I KNOW YOU CAN FLY WHIT ONLY 1 ENG BUT WOULD THE AUTOPILOT ACT AS FAST AS AN PILOT DO. AS AUTOPILOT IS ONLY PROGRAMED HARDWARE/SOFTWARE AND IT IS HARD TO PROGRAM SITUATIONS.

Your Caps Lock button has a problem :wacko:

Share this post


Link to post
Share on other sites

There are too many external factors involved for an autopilot to make an adequate go or no-go decision in an emergency.

Brian

Share this post


Link to post
Share on other sites

It's too prevent stupid people from stealing aircrafts... it's ok if they come down on autopilot but not going up :)

  • Upvote 1

Share this post


Link to post
Share on other sites

An autopilot has a reaction time which is nearly 4 times higher than the reaction time of a pilot.

If there is a rejected T/O, the pilot has to make complex decisions which the autopilot can't do in the same small time window.

Last but not least, the autopilot systems in modern aircrafts are designed to have a minimum height until you can activate the autopilot.

Share this post


Link to post
Share on other sites

An autopilot has a reaction time which is nearly 4 times higher than the reaction time of a pilot.

Where did you get that info?

Share this post


Link to post
Share on other sites

There are too many external factors involved for an autopilot to make an adequate go or no-go decision in an emergency.

Brian

Could be, but are these factors not the same when you need to decide to land or abort? All these comments do make some sense but they seem to ignore the fact that landings are also complex and inherent a mistake is far more problematic.

Share this post


Link to post
Share on other sites

well there could be problems at departure becaus how should the aircraft pull the nose up as there is nothing that can tell the autopilot to do so becaus the speed and lift are diferent caused by turbulence and other facts. At the moment there is no ILS for departure. so the aircraft have no indication about how it should controle the aircraft.

Share this post


Link to post
Share on other sites

This is one that does not have a absolute answer, but I got three airline pilots with in total over 50.000 hours logged to help me find the answer that makes most sense and is most complete.

Aircraft fly on autopilots, they even land automatically. Why don't these aircraft take-off automatically?

Can aircraft file their own flightplan?

Air Force Global Hawk flight test evaluations are performed by the 452nd Flight Test Squadron at Edwards AFB. Operational USAF aircraft are flown by the 9th Reconnaissance Wing, 12th Reconnaissance Squadron at Beale Air Force Base. While testing the first two production aircraft, a delay in take off required a late night call to file a flight plan. When FAA received the call to fill in fields on his computer for SOBs (souls on board), his reply was, 'the computer can't take 0'.

See article: http://wapedia.mobi/en/RQ-4_Global_Hawk

L8er,

Marc

Share this post


Link to post
Share on other sites

Aircraft fly on autopilots, they even land automatically. Why don't these aircraft take-off automatically?

Hmmmm..... I'd like to have a try.

Why don't these aircraft take-off automatically? These aircraft's don't have that type of autopilotes installed. And there are not any aoutopilots on the market that can do a fully auto take-off. Why they have not made a software and hardware to make a fully automated takeoff is another question. A question that was not asked for ;)

Anywhy, does not the B-767 have a semi auto takeoff in it's FMC? It's a long time since I've sett up the FMC in Level-D 767-300 now, but i think I remember you might get it to perform a "auto takeoff". The onely thing you do is stearing the plane with the nose weel down the runway, and the plane do the rest. Throttle, roll etc. If this is true, and I remember correct, there must be a problem with the ground handling through the nose wheel they have not solved yet. At the moment the autopilot controlls the engines and the controll ruders. There is also autobrake system and auto speedbrake/spoiler system, but they are not sett in the FMC or the autopilot. So it might be the nose gear that makes the problem so far.

What makes it difficult to implement a autopilot through the nosewheel i don't know? Might it be bcause of sidewinds? Lets say it's a problem with the winds comeing from the sides of the runway. There might be a problem right before the roll, while you're still on the ground. You are on the ground, but still the aircraft is begining to behave like it's airborn, and the winds from the sides starts to take effects on the aircraft. When should the computer go from ground handling to airborne, and is it realy possible to make a autopilot to do it? What is different from a takeoff and landing might be that the autospoilers ends the flight at the moment they are deploid/in use. The difference between flight and groundhandling is "shorter". And the sidewinds do not have the same effects on the aircraft bcause the wings suddenly produse alot less lift instantly after landing when the spoilers have been deployd.

Well, sorry for my bad english..... this was my thoughts about this case, hope you understan what i try to write.

Share this post


Link to post
Share on other sites

Cann't see any reason why an auto take-off system could not be built, if this would be requested.

So I think, the costs are not in due proportion to the rare occasions, where this would be necessary.

The aircraft can wait some minutes on the ground until visibility is sufficient.

The costs of the landing on an alternate airport are much higher.

Albrecht

Share this post


Link to post
Share on other sites

Maybe simply because take off is easier than landing. When you're in air and fly with full flaps and at low speed, your aircraft goes down. Pitching the nose up doesn't solve the problem, the pilot must use throttle. This use requires millimetrated control, that's why it's so difficult. Therefore the Human invented AP.

Share this post


Link to post
Share on other sites

They probably are able to, just not certified.

I know FS Default aircraft aren't realistic at all (Why I fly PMDG) but I

set up a experiment.

1. Placed aircreaft on runway.

2. Set 6000 as initiall climb altitude.

3. Set VS t0 500 fpm.

4. Set Loc Capture on with Loc tuned in Nav 1

4. Hit the auto pilot on.

5. Set TOGA power.

6 At 156kts hit the alt hold button.

Viola, auto takeoff, felt scary thought like probable tailstrike but it did the job, its just not a certified way of taking off.

Share this post


Link to post
Share on other sites

This Contest has already gone Three Days :wacko: How long does it take to find a relivent answer for this?!?

Share this post


Link to post
Share on other sites

I would like to make another point.

Even though one could make such a system it makes very little sense for a number of reasons mentioned already, but if such a system was installed, who should control it? The pilot or the air traffic controller? At most bigger airports, my impression is that the SID's are not that often used, the airplanes are vectored out in the most efficient way by the controller (at Gardermoen for instance they don't even want the pilots to turn on the autopilot before reaching 6000 feet), at smaller airports the SIDs are almost never used, as a direct route is preferred for both saving time and fuel.

I guess you could say that these factors would also apply for landings, but there is a difference, when landing you are at least holding a pre-defined path (the glideslope) for some nautical miles, on takeoff however, pilots often start maneuvering on their own paths after a few seconds in the air.

BTW: My impression is that most pilots often only use the autopilot en-route, handling both depatures, arrivals and landings by hand, if the weather permits.

Share this post


Link to post
Share on other sites

Well another reason for auto take-off not to be impelmented may be the lack of hands on flying performed by the pilots. Today most of the time pilots would switch on the autopilot as soon as 500 ft in to the air and switching it off again as late as 500ft AGL. Recently this issue is surfacing in aviation world and some people claim that some accidents could have been prevented if the pilots would have had more hands on flying experience. So the reason could be that the pilots are already performing too much flying via switches and knobs instead of yoke/sidestick and thus loosing the feel for the aircraft.

flyhigh

Share this post


Link to post
Share on other sites

Well another reason for auto take-off not to be impelmented may be the lack of hands on flying performed by the pilots. Today most of the time pilots would switch on the autopilot as soon as 500 ft in to the air and switching it off again as late as 500ft AGL. Recently this issue is surfacing in aviation world and some people claim that some accidents could have been prevented if the pilots would have had more hands on flying experience. So the reason could be that the pilots are already performing too much flying via switches and knobs instead of yoke/sidestick and thus loosing the feel for the aircraft.

flyhigh

Hmm, my impression is quite the opposite. That pilots mostly fly by hand and even according to VFR rules when conditions permit, only using the autopilot enroute...

Share this post


Link to post
Share on other sites

Hmm, my impression is quite the opposite. That pilots mostly fly by hand and even according to VFR rules when conditions permit, only using the autopilot enroute...

Well I am not going to argue with that but it all comes down to the operating procedures of the airline. One thing is for sure tough: autopilots can fly airplanes more efficiently and more precisely. And you also have different sorts of pilots. Some will love to push buttons and switches all the way down and some prefer hands on flying. While I do agree with the point that in general pilots will opt for a visual approach if weather conditions and traffic situation permit but I would disagree with the autopilot only being used enroute. I think it comes on pretty soon after take-off and is switched off quiet late into the approach in genral.

Share this post


Link to post
Share on other sites
Guest
This topic is now closed to further replies.
Sign in to follow this  

×
×
  • Create New...