Use of the Sky Pointer in GA instrument flying.

[Tee Emm]

Some years ago, there were several fatal accidents in Europe involving both jet and turbo-prop aircraft, where the contributory cause was thought to be pilot confusion with the Sky Pointer indication in the artificial horizon. As these happened in IMC the aircraft entered an unusual attitude from which the crew failed to recover.

For example Russian designed types had the so called Sky Pointer at the bottom of the AH rather than the conventional design which is the top. Investigations concluded pilots used to flying Russian cockpits and then transferring to Western (Boeing/Airbus etc) aircraft could be confused if interpreting the ADI in IMC or night and possibly run the risk of applying incorrect flight control direction to level the wings.

A problem may arise if new student pilots are trained during instrument flying using a type of artificial horizon that may differ in presentation from mainstream artificial horizons or EFIS Primary Flight Displays installed in say Boeing/Airbus. When that happens, the Law of Primacy comes into play. Primacy, the state of being first, often creates a strong, almost unshakeable impression. Things learned first create a strong impression in the mind that is difficult to erase.

Flight Training Adelaide enjoys an excellent reputation for graduating cadet pilots for various airlines. These include Virgin Australia, Cathay Pacific and Dragonair. These airlines have Airbus and Boeing equipment.

Multi-engine training for cadets for these airlines is conducted on the Diamond DA42 twin engine trainer which is EFIS equipped. It is my understanding that the EFIS display in the DA42 has the Sky Pointer indicator at the bottom of the PFD and not at the top. If the aircraft banks right the pointer in this case also goes right. Sky Pointer is probably the wrong word, but you get my drift. In other words, it works in reverse to a standard Sky Pointer. It also means that the traditional advice by instructors to level the wings as part of unusual attitude recovery by applying control wheel in the shortest direction to the Sky Pointer, is no longer valid.

Cadets going directly into RH seat of the Airbus or Boeing fleet of the parent airline will then be faced with the traditional Western EFIS PFD where the Sky pointer is at the top of the ADI. Typically the Boeing 777, A330, A320 and Boeing 737NG.


It is all very well saying they will soon get used to the different Sky Pointer position. That maybe so - until the proverbial dark and stormy night when the captain is temporarily absent from the flight deck and the unmentionable occurs and the autopilot disconnects leaving the cadet to hand fly in IMC. Then watch out for the Law of Primacy when under stress. And we all remember what happened to the Air France A330 over the South Atlantic Ocean....

Whether other similarly EFIS equipped training aircraft of FTA have the same design as that in the Diamond DA 42 I don't know. But there is a strong case for FTA to learn the lessons of past accidents involving ADI Sky pointer presentations and fix the problem quickly. It should be relatively simple; involving a pin change perhaps? Surely the local CASA FOI should have discovered this potentially serious anomaly well before this and done something about it?


Or is the subject matter not really a flight safety issue?

[dubbleyew eight]

I do not understand what you are talking about.

in an american artificial horizon the aeroplane symbol is fixed and the horizon background moves to remain parallel with the actual horizon.

in some russian systems as far as I know the background horizon remains fixed and the little aeroplane moves.

I wouldnt have thought it a problem. how many russian systems have you ever seen?

https://encrypted-tbn3.gstatic.com/images?q=tbn:ANd9GcQRaxp8Zy3ouPh_SRB0XpExfwsNarRmzkERyjDG9hK-jee7emek

http://image.shutterstock.com/display_pic_with_logo/11298/11298,1153503415,31/stock-photo-aircraft-attitude-indicator-1576164.jpg

[dubbleyew eight]

maybe this ???

http://www.skybrary.aero/images/thumb/Artificial_Horizon_Formats.jpg/500px-Artificial_Horizon_Formats.jpg

[Oktas8]

Tee Emm, it looks like you are a little confused between two concepts.

1) Russian vs. Western AH formats. Dubbleyew eight's second post illustrates this. The cognitive difficulty of converting from R to W type has been associated with accidents such as you've mentioned. However I doubt anyone in the English speaking world uses Russian AH designs for flight training, so it's more a problem in e.g. Africa and Eastern Europe, where mixed fleets occur.

2) Sky pointers vs. Roll pointers on "conventional" Western AH displays. Dubbleyew eight's first post shows first a sky, then a roll, pointer. Generally GA displays use roll pointers, airliners sky pointers. Is this your beef with FTA?

Garmin attitude indicators can, AFAIK, be set at the factory to display either format, and in the DA42 are usually set to roll pointer style. Again AFAIK the differences are not associated with accidents in the airline world, although some pilots (http://jetbrief.pbworks.com/w/page/22929305/Piston_vs_Jet_Roll_Indicator) claim to be initially confused by the difference.

It also means that the traditional advice by instructors to level the wings as part of unusual attitude recovery by applying control wheel in the shortest direction to the Sky Pointer, is no longer valid.

GA aircraft have been using roll pointers for many years. If you have been trained to set attitude by looking at the aircraft symbol in the centre of the display, you will not be confused. If you have been trained to set attitude by looking at the top of the AH, oops, you had a weak instructor. (Weak in that area, I mean.) But it's not a deal breaker, so relax.

[AmarokGTI]

Your information is wrong.

Also, any issue you have with FTA is actually an issue with the Garmin G1000 setup. Have you used it before? It is brilliant. But it doesn't have a sky pointer. And certainly not at the bottom of the screen.

[LadyLlamapilot]

That top example there in dubbleyew eight's first post completely ballses me up. Im only used to the bottom one, and the plane seems like it is going the other way to me when the "sky pointer" if you call it that, is out the other side.

[601]

One thing that sticks in my memory fro way back when is seeing an "up-side-down" AH on the panel of a BOAC VC10.

[BreakNeckSpeed]

I recall a mentor of mine telling me that all confusion with the different types of AI could be avoided by the application of an appropriate internal scan of the AI - something I had never heard of in my initial MECIR years ago.
Much of the confusion people experience in the thick of it arises from looking to the Pointer for bank direction and angle - which is not its purpose!

The internal scan workcycle referenced was Dot (for attitude reference), Wings (for direction of bank relative to horizon), Pointer (for specific angle of bank), and in that order. Works a treat!

Although I have yet to use a system with a pointer at the bottom of the indicator as described in the OP (disclaimer ;)), an understanding of how to use the instrument correctly (which seems to be lacking at least in the low end of the industry) and the application of an effective workcycle would mitigate to some extent the possible issues in transitioning from one type of AI to the next.

[sheppey]

Reading the original post the author makes the valid point that the students should be taught with their sponsor's equipment in mind. All Boeing and Airbus flight instrument displays are designed with the Sky Pointer at the top of the PFD. This facilitates prompt recognition of the direction that roll recovery should be made ie turn the shortest way to the Sky Pointer.


It defies logic (and disregards the Law of Primacy) to train students at this particular flying school in an instrument flying technique which is in reverse to the instrumentation of the jet transport they will soon fly.

[Car RAMROD]

Quote:
That top example there in dubbleyew eight's first post completely ballses me up. Im only used to the bottom one, and the plane seems like it is going the other way to me when the "sky pointer" if you call it that, is out the other side.




Correct, that's the trap for people unfamiliar/not told about them.
When I first learned a sky pointer I began to roll the wrong way once. Silly. But I learnt. Now I train other pilots. Amongst our fleet we have both types, and the first time the newbies ever get in the planes with a sky pointer I've briefed them, and demonstrated it.




The reason why you think you might be going the "other way" is rather simple once it has been explained to you.


Now, you are familiar with the type highlighted in the bottom image, lets call that the "normal" type for now. If you look at your bank indicator (the one that points to the degrees bank you have, at the 12 o clock position), its very easy to see which way you need to roll to bring it back under the wings level indicator- to the right.


The sky pointer is opposite. You roll left (both images are left banks) and the bank indicator goes out to the right hand side. Now if you are used to the "normal" indicator and apply your previously learned mindset, you can easily think that you've got to roll left to bring the pointers back in line. This, obviously, is not the correct move and you'll steepen the bank.




Of course, it's not the only clue you should be using to determine what's going on. But it can easily be misread by those new to it.
It's best to treat the pointer as purely angle, and not direction. Use the wings on the display for direction!

[Jabawocky]

Simple solution. Put the wings level…..if **** hits the roof :eek:, put the wings level again. :E

[sheppey]

Just read a book called "Recollections of an Airline Pilot" by Peter Orange, a retired KLM captain. He recalls doing full stalling at 10,000 ft with gear down and landing flaps in an actual DC8, as part of an FAA requirement. As the aircraft stalled accompanied by heavy buffet, he levelled the wings and applying power eased the nose down to regain speed.

At that instant his seat broke loose and he slid fully to the rear. The buffet was so heavy he was unable to read the instruments initially. As the instruments came into focus the altimeter was seen to be unwinding with alarming rapidity.

In his own words "the artificial horizon seemed to be almost a blank, until I spotted the Sky Pointer marker in approximately the 150 degree position indicating we were close to being inverted. Fortunately, I was able to roll the aircraft in the correct direction to regain a wings level attitude, despite my stretched position. With wings level I was now able to reposition my seat and recover from the dive towards a very cold looking North Sea. To avoid stressing the aircraft unnecessarily this recovery was quite gentle, and full control was effected several hundred feet above the water".

Angle of bank indicators can be at the top of the artificial horizon or at the bottom, as previous readers have explained. But once beyond normal angles of bank such as in an unusual attitude, the number of degrees of bank become academic since they could be beyond 90 degrees.

The author then explains: "If the Sky pointer is seen to move from its normal upright position, the direction of roll to return it upright is obvious.
If, however, its movement has not been seen (as in the case of the DC8 150 degree roll described earlier), then the direction of corrective roll to level the aircraft is not immediately obvious, particularly when it is in a completely unusual position.

In the incident described above, the whole episode had lasted barely 15 seconds, but we had fallen at some 30,000 feet per minute as registered on the FDR. As a result of this incident we installed an "Upset" switch in the simulator enabling us to train pilots in recovery from unusual attitudes. To our surprise, a considerable number of pilots had great difficulty with this exercise. Those who had the most difficulty were the pilots who had never undergone full aerobatic training."


Although the incident above happened in 1967, it shows that artificial horizons on jet transports had sky pointers (angle of bank indicators) at the top of artificial horizons even then. Even the Boeing B17 Flying Fortress had them so they are nothing new. Seems to me the OP has made a sound case to have the EFIS in training aircraft standardised to what is today considered normal displays with the angle of bank indicator at the top rather than at the bottom of the artificial horizon or PFD. This is particularly relevant in flying schools specialising in the training of cadets for airliners

[Oktas8]

Seems to me the OP has made a sound case to have the EFIS in training aircraft standardised to what is today considered normal displays with the angle of bank indicator at the top rather than at the bottom of the artificial horizon or PFD.

Having quite a bit of time in DA42 trainers myself, I think the OP does not fully understand the difference between roll pointers and sky pointers.

No G1000 PFD presentation AFAIK has a bank indicator at the bottom of the AI. (It is possible that FTA uses a customised display, but no-one has categorically said that. Is anyone stating that from personal experience?)

The G1000 in light aircraft uses a standard roll pointer. This is considered a normal display. The roll pointer is at the top of the display, as is normal, usual, standard.

If the sky pointer is a more useful indicator, then perhaps GA should change from roll pointers to sky pointers. (Both are at the top of the AI.) I've not seen any evidence that one is substantially better than the others.

Don't get the difference between roll pointers and sky pointers? Google is your friend!

[mahogany bob]

Apologies for taking 8 years to add to this thread!!
BUT I think it is still valid.

In the RAF during training on the Jet Provost and then later flying the Vulcan and the Nimrod I never had any problems interpreting the Ground Pointer even when recovering from UPs.
Later converting to the AWACS ( B707 ) I immediately found the Sky Pointer difficult to use instinctively and sometimes had to think twice before levelling the wings - this is most undesirable when flying at night in extreme turbulence etc !! Ie turning the wrong way you COULD in extremis end up inverted!
Later when instructing in the Flight Sim I found that many others also disliked the Sky Pointer!

SOLUTION

Imagine that you are wearing a German helmet ( the one with the spike sticking out of the top ! ) - this is is the Sky Pointer,
Using this mental image you immediately know which way to bank to regain S & L !

Try it ?