Instrument Pilots

[Goldenhawk]

Friends, the following is an extract from a recent GASIL magazine, and I was hoping the more enlightened may explain the theory involved here-certainly food for thought!

'Although we have no official confirmation, we are reliably
informed that one of the modern generation of light aircraft
(foreign- registered) suffered a rather unsettling failure last winter while flying above cloud. The particular aircraft’s instrument
system is electrically powered, including the attitude and direction
indicators as well as the turn coordinator.

This failure appears to have happened to the pilot of the
aircraft involved. A total electrical failure left him without
either instruments or radio, and in a situation which required a let
down through cloud. Fortunately, in this case, during his instrument training, his instructor had shown
him that, in extremis, it is possible to maintain straight flight using
only the magnetic compass and the aircrafts natural stability?

Turning onto South (the only direction in which the method
works)? (why?)

the pilot reduced power and was able to maintain direction by
responding to deviations in compass heading indications until
he came out of the bottom of the cloud.
The method described has been used several times in the
past, but is not often practised. Those of us who are qualified to fly on instruments and who have not been taught the technique might consider practising it in simulated instrument flight conditions with a safety pilot, especially as we believe that the NTSB (the American AAIB) have reported a fatal accident in an aircraft with a similar instrument fit recently which appears to have also involved a total electrics failure. '


Regards:O

[Grainger]

Turning onto South (the only direction in which the method
works)? (why?) Presumably something to do with turning and acceleration errors. When heading South you will get zero acceleration error on the compass card, helping to keep a straight course, and (in the Northern Hemisphere) the compass will over-indicate any turn, providing instant feedback of any course deviations.

[Letsby Avenue]

Blimey - Are you saying that this guy flew thru cloud and maintained attitude, direction, speed and RofD all from the E2C?:uhoh:

errrr hell of a ride methinks... I would have ended up wearing the aircraft :}

[MightyGem]

Ah, Letsby, remember that he was in a fixed wing. Trimmed out S & L
in a gentle descent before entering the cloud and it will virtualy
fly itself.

As an aside, I used to cover up both Horizons in the Lynx when
conducting IRTs, and get people to recover from a UA using just ASI,
VSI, altimeter and compass(not the standby compass I must admit) just
so that they could see that it could be done.

[IHL]

In WWI pilots; were taught to spin through the clouds if caught on top of a layer.

The theory being that if the aircraft is held in a spin it is in control and not exceeding any airframe limitations. Thusly upon exiting the lower cloud layer they could recover and continue on their merry way.

[Hughes500]

Teach some of my better students in the instrument appreciation the following. Maintain ht and heading using only DGI,ASI and Manifold Pressure gague. You will be surprised how easy it is if you do everything very gently. Namely in a 300C hold 20 inchs of MP and 60 kts you will be S & L. Reduce MP to 18" and hold 60 kts you will descend at about 300 ft a minute. Reduce speed to 50 kts and 16 inchs and ROD will be 500 ft a min.

The things one does with students on the boring 5 hours insrument appreication !!!!

[Aesir]

"Turning onto South (the only direction in which the method
works)? (why?)"


This guy must have been trained in the US in the art of instrument flying. This is basic "IFR 101" in the lessons I took many years ago in the US.

If all gyro´s fail and you are have no other option than do a instrument let down thorugh the clouds, descend on a southerly heading using the magnetic compass, who due to the "Northerly turning error" in the northern hemisphere will indicate turns in the correct direction at a higher rate than it is actually occuring.

We did this at Dick Hill helicopters Springfield MO in a Enstrom through thin cloud layers with the gyros covered up and under the hood.

Sometimes people discuss the quality of training in the FAA system versus the JAA. I am now myself a JAA Flight examiner and I am always amased that the quality of training is actually worse in Europe than what I have self experienced in the US, particularly theory. Things are kept less complicated and you are taught and required to know the basic stuff which in the end will keep you alive in the real world.

In the JAA ATPL course, sadly about 90% is useless knowledge! In the US you have to get an interview with an FAA examiner to prove your experience be even allowed to take an ATP course where you learn things that are applicable and in the checkride your flight performance has to be 1st class.

Well at least thats how it was years ago when I was in the States.

[Lowlevldevl]

So a Northerly heading in the Southern hemisphere, right?

[Hughes500]

Mr Selfish, have you tried what I suggested under the hood ? It does work but only if you know the ac. There is a direct relationship between power, airspeed and height.
Without getting carried away, in a 300C

18" = 50 kts S & L
20" = 60 kts S & L
22" = 70 kts S & L

Now if you hold 60 kts airspeed and increase mp by 2" you will climb at 500 ft a min.
Hold 50 kts and reduce map to 16 " and you will descend at 500 ft a min

I can assure it works every time in the particular machine I teach in. I would never suggest doing this for real in IMC but if you had a complete eletrical failure you could make a pretty good go using these instruments. Before any smart alec says the dgi is electrical I use this as the compass is mounted 9" above instrument panel and you could cheat by looking out of the ac.

The reason I teach using these figures while not only vfr flying but under the hood it gives the student targets to aim at so he does not continually chase all the instruments.

Go try it and let me know, by the way having been taught by UK mil I can fly / have flown on instruments for real, but I do hold an IR.