aeroplane controls

[Fritag]

It's so context dependant that there's obviously no one answer.

The easiest context is obviously a single engine piston VFR and attempting to land.

Then it's a question of safety margin.

I bet some guys could safetly and repeatedly land one with no instruments- with or without engine - just using mk 1 eyeball to judge attitude and the feel through the airframe/stick and maybe wind noise to avoid stalling. Depends on experience and currency.

For me the next most important instrument would be revcounter or manifold pressure gauge - whichever is fitted. I say this because correct engine revs plus correct attitude (mk 1 eyeball) equals predictable speed. Easy to eyeball your flightpath to the runway, then set your power - maintain the flightpath and then all things being eaqual the speed will be ok. Some variation with weight but err on the side of caution on the power.

Classic flying instruction for any given situation is PAT. Power - Attitude - Trim. Only then do you check your speed - to confirm it's what you expect it to be and to fine tune it.

Of course. If you've never been taught to fly that way and/or you can't remember the correct power setting - then you'd better have the ASI instead. Chances are though you'll end up with a much less stable approach as you keep thrashing around with the throttle 'hunting' to keep the right speed.

Cool debate though. Matter of opinion really.

Steve

Edited April 4, 2013 by Fritag

[Fritag]

Still (a bit loosely perhaps) under the topic of aeroplane controls here's an old chestnut (as Gollum said to Bilbo) that may or may not have been discussed on BM before.

On finals - what control governs speed and what control governs rate of descent? Does anyone care?

This'll mean something to the PPL guys like Iain and Kirk et al. but is admittedly a bit anal (for which apologies - and I am not and never have been a flying instructor and so am not claiming particular wisdom on the point).

Steve

[Stramash]

Still (a bit loosely perhaps) under the topic of aeroplane controls here's an old chestnut (as Gollum said to Bilbo) that may or may not have been discussed on BM before.

On finals - what control governs speed and what control governs rate of descent? Does anyone care?

This'll mean something to the PPL guys like Iain and Kirk et al. but is admittedly a bit anal (for which apologies - and I am not and never have been a flying instructor and so am not claiming particular wisdom on the point).

Steve

Stick for speed . . .

[bentwaters81tfw]

You have a combination of throttle, stick and flaps. I had a tendency to set the flaps at 30 degrees (Cessna 150), point the nose at the numbers and adjust progress with the throttle.

On three out of four of the Ipswich runways, there were height obstructions on approach, and finals were normally taken from 600 feet. I would judge it as above, then kill the throttle over the threshold.....straight onto the numbers every time.

[Mark]

Interesting question with many answers as it really depends upon the aircraft in question. I 'think' I'm qualified to answer this, so here goes...

As Iain said earlier, in visual conditions in a light aircraft, then none really, but I'd sure like to know what speed I am doing! After gaining a lot of experience on a particular aircraft type, I would 'suggest' that the pilot gets the fell of the aircraft controls and could fly a safe enough speed to land the aircraft. At very slow speeds (in fact at high angles of attack) the aircraft is at risk of stalling and that could ruin your day on final approach. But at slow speeds the controls very light and sluggish, as well as other physical indications such as vibrations and a very high nose angle, so an experienced pilot flying a light aircraft should be able to get the aircraft safely down and walk away with no instrumentation at all.

Now, increasing the complexity of the aircraft also increases the reliance on instrumentation and automation. As has already been said, the larger the aircraft, the more distant the pilot becomes to the external conditions and although wind noise can be heard, it is not enough to gauge airspeed by at all. All modern airliners have 'glass' instruments or Electronic Flight Instrumentation Systems (EFIS) which combine the traditional four instruments shaped as a 'T' on the instrument panel onto one TV screen. These instruments would be the Attitude Indicator, the Direction Indicator, the Altimeter and Air Speed Indicator. Along with the other two that make up the six, the Vertical Speed Indicator and Turn / Slip Indicator, this provides the pilot with a handy single screen to get all the information from during the critical phases of manually flown flight. Now, if the screen fails, the pilot loses the lot! But no problem, a turn of a switch will recover the information from the second Display Management Computer (Airbus term, Boeing no doubt has a similar term) and display on his screen the identical images that are seen on the other pilot's screens. Unless, of course, the actual screen has failed whereby it won't display a thing.

So, instrumentation fails, try switching, nothing happens, so you say 'You have control' to the other pilot, no problems. Until his screen fails! Now this is not your day, but there are standby instruments that resemble the more traditional instruments and these can be followed quite easily to ensure a safe outcome; i.e. a landing at a suitable airport.

But that is the outcome of a possible electronic failure, perhaps a computer related etc. What happens when the sensors providing the information become affected, by icing or another blockage perhaps? In this case the instruments are working perfectly normally, but they just don't tell you the right information! This is, of course, a hazardous failure and one that has recently been the cause of a major accident with an Air France A330 crossing the Atlantic from Rio de Janeiro to Paris on 1st June 2009.

But all commercial pilots are trained to recognise unreliable airspeed and unusual attitude scenarios, and the way to ultimately manage the situation goes right back to basics with specific Power settings and a correct Attitude being flown according to stage of flight and speed that needs to be maintained. Believe me though, it is quite unnerving to be sitting there trusting a page of a check list when your instrumentation shows that you are in a high speed, spiralling descent! But that is what needs to be done and training is improved all the time to cope with this, happily, very rare scenario.

That covers the instrumentation side of things, but what about flight controls? The flappy things that wiggle and change the course of the aircraft are controlled hydraulically but are electrically actuated via inputs from either a traditional control yoke in the case of Boeing, Embraer etc. or by a side-stick in the case of Airbus and some fighter aircraft, such as the F-16. Again, there is a lot of redundancy before you left with nothing and that would be an incredible rare situation, but with failure of everything, you can still fly the aircraft via the trim wheel and power settings. Failure of both engines also makes it slightly more interesting, but during my last simulator training session, we revisited a dual-engine failure whilst at 24,000 feet over Kent. It all gets very busy whilst the primary concern is to stay alive (no pressurisation means cabin pressure increases and no oxygen, so Oxygen masks are on straight away) then try and restart at least one engine whilst also managing the position of the aircraft in relation to somewhere suitable to land! You'll be glad to hear that I got the aircraft safely onto the tarmac at Gatwick and we all got off and went to the hotel for a beer...

[Vickers McFunbus]

Stick for speed . . .

It must have been a loaded question; it all depends on which technique you've been taught and/or are using!

[depressed lemur]

What is all this talk of engines? In a glider you can get away with stick, eyeballs and ears.

[Fritag]

It must have been a loaded question; it all depends on which technique you've been taught and/or are using!

Didn't intend to be a loaded question. Apologies if it read that way.

To some it is axiomatic. Stick for speed. Power for rate of decent. Anything else is heresy.

I find it easier to think of it this way so I agree with Stramash. Stick for speed.

Even in a glider - stick for speed but this time airbrakes/side slip etc for rate of descent.

But I know there are differences of opinions both per se - and situation dependant..... So I just thought I'd throw it in as there are some knowledgeable guys out there (present writer excepted!)

Edited April 5, 2013 by Fritag

[xffw45343tg]

It must have been a loaded question; it all depends on which technique you've been taught and/or are using!

Apparently RAF prefer "Point and power" ('cos they used to have mostly have fast pointy things) whereas your average Cessna/Piper jockey will most likely have been told to trim for the desired approach speed and then mostly use the stick. But you knew that. ;-)

PS/ Apparently the footrests do something too but my brain still can't take advantage of this without my considered intervention...

[Vickers McFunbus]

Didn't intend to be a loaded question. Apologies if it read that way.

To some it is axiomatic. Stick for speed. Power for rate of decent. Anything else is heresy.

I find it easier to think of it this way so I agree with Stramash. Stick for speed.

Even in a glider - stick for speed but this time airbrakes/side slip etc for rate of descent.

That'd be why I've been struggling to land a glider all week.

Apparently RAF prefer "Point and power" ('cos they used to have mostly have fast pointy things)

Indeed. I work on the principle that the thing between my legs (stick or yoke) should be for pointing me in the correct direction, with power/things sticking out of the aeroplane to sort my speed out.

[Fritag]

That'd be why I've been struggling to land a glider all week..

Blimey, that's a long time to stay up in a glider

Edited April 5, 2013 by Fritag

[depressed lemur]

Blimey, that's a long time to stay up in a glider

Thermals, lots and lots of thermals.

[bentwaters81tfw]

yeah, it's been a bit nippy.

[Mark]

The stick for speed, power for rate of descent discussion is dependant upon what you are flying. C152? yes, Airbus A340? no.

[xffw45343tg]

The stick for speed, power for rate of descent discussion is dependant upon what you are flying. C152? yes, Airbus A340? no.

..and there was I thinking you just capture the ILS, press the "land" button, reach for "Professional Pilot News" and sip on a latte...

[Mark]

That'll be the morning shift! Afternoon sectors it's tea and maybe a hot chocolate for those late nights. As for PP News? Airfix Model Mag on the iPad for me!!

[Fritag]

That'll be the morning shift! Afternoon sectors it's tea and maybe a hot chocolate for those late nights. As for PP News? Airfix Model Mag on the iPad for me!!

Wot about BM on the Ipad? Some airlines have wi-fi now don't they? - even for us cattle. Don't the Lords of the Sky have it?