Instrument flying; how important is the Attitude Indicator?
 

Attitude Indicators.....primary or secondary instrument for Instrument Flying?

Depends on mode of flight. Normally a supporting instrument. In cruise flight: primary pitch = altimeter, primary turn = heading indicator, primary power = airspeed. (if you remember your Army days...you were only going to have the attitude indicator for the ITO, then it was going to "fail")

Primary
 

I did 8 years in the Beaufort Sea and high Arctic in the 212, 61 and 76 much of it at night. When we took off from a rig deck the calls are: PF "coming up" (applies power at least 15% above hover power), PNF calls "20", "40", "rotate" (5% nose down on the AI), PF calls "positive rate" (of climb).

I actually had an AI fail (slow tumble indicating roll right and nose down) with no flag just after rotation during a rig departure at night. I warned my co to get ready to take control if needed as I transitioned to the standby horizon in the centre of the panel.

We also did a lot of night slinging. When training new pilots I can recall a few times when the AI went all Grey then all Black, .... then all Grey again. :hmm: I suggested to the lads that when this happens it is simultaneously "wings level" (on the AI) and "pitch to zero" (on the AI), then evaluate.

Finally, all our engine out on takeoff drills were predicated on "x degrees nose down" (on the AI), accelerate to Vtoss, level (on the AI), then accelerate to Vbroc.

So my vote is "primary".

An AH is not required for DayVFR....simply maintain visual reference with the ground at ALL times - nuff said

"Attitude Indicators.....primary or secondary instrument for Instrument Flying?"

I was taught that it was useful, but a backup. The Army taught me to fly partial panel (on the Beaver), which was back in the day when they were notoriously unreliable.

Phil

Primary is the attitude of the pilot... The helicopter didn't fly into the clouds, the pilot did. In that situation most of would got a strange feeling of rather being on the ground, turn around and go to plan B, land. Some pilots apperently do not get that feeling. I have experienced pilots wo wanted to fly a Robinson helicopter into an area with forecasted severe turbulence. It was very hard to convince them of not doing that revering to the limitation sector of the afm/poh. People wo wanted to fly a aerial inspection returnflight from homebase in bad weather while our schedule has plenty space and the coming days the weather should be fine. In my opinion it was not commercialy a good idee...CPL... commercial pilot, think of the costst.
As said before, in my opinion it is about decision making, planning, respecting limits, knowing your ability and avoiding commercial pressure or your own pride.

Safe flights to all

Surprising attitudes (pun intended) to the use of the AI/AH - it is the primary instrument for instrument flying as anyone who has taught IF will tell you.

It is even more important in RW compared to FW since the platform is so much more unstable.

Yes, you can fly straight and level in the cruise without using the AI/AH but anything that requires manoeuvering with any accuracy needs the AI/AH.

Spot on Crab - as anyone who has flown a Whirlwind 7 in cloud will surely attest. AI always the centre of ones scan.

That's amazing, been humping the Cyclic for 28years the last 11 in extreme Mountains & I never ever look at the AH/AI, not once :ooh: yet I gotta do some extreme manoeuvres in some pretty narrow gorges in weather? I was trained that my Airspeed indicator is my stick position (attitude) indicator & I look outside for everything else except, for speed & engine gauges. I never realised I needed an AH for all this flying :eek: always learning but :8

...and what do you see outside in IMC???

skadi

DayVFR thread into deliberate illegal IMC
 

ow You mean approaching beer o'clock??? Well, well before IMC; land, put the machine to bed, then park myself on a comfy chair & stare at the next beer through my special IMC beer goggles :8

I think VF is playing with you ....!! Flying in his area is all VFR , even in v poor viz . No option to climb . Apart from that ...he is flying a single !

"Here Here",,,totally agree and apart from that,,,I have No words for the stupidity of this pilot! :ugh:

I know, and I am absolutely with him concerning his flying in Nepal. But he quoted [email protected], who surely talked about flying in IMC and there you should use an AH

skadi

However, if the mountain flying is extreme and in poor weather, the AI is still an important instrument as it helps you avoid false horizons caused by the slope and strata of the mountains which can be very confusing.

Or you can just pump the cyclic, ignore the AoB and its effect on your power requirements........................

Spot on again Crab. The AH in clag is your life saver................VF I admire your flying career enormously but if you have never looked at your AH you are a very brave man - and have never flown a Whirlwind 7 in cloud!!!;)

i have never looked at an AH either. none of my helis have one...

I'm wid You SuperF...only the AH 's here are not maintained to an IFR standard so it'd be damn dangerous to trust one. I doubt any DayVFR machines AH is maintained :} I'm sure Your flying in the NZ Mountains that too have some crappy weather :*

Hey crab......weather in the Himalayas is extremely ****ty, layered & very dodgy 9 months of the year, stooging about in valleys that have ridge-lines up at 25,000' whilst flying down at 10,000' & yet, I've never been IMC ever :ooh: I've yet to use the AH & yes one eye is always glued to the FLI, another eye to the IAS & my third eye is always scanning outside :8

Stay Happy...Stay VMC :cool:

Please correct me if I'm wrong; the AH is not a required instrument legally for DayVFR? :confused:

Once You've pressed on for far too far & Your thinking that an unserviced AH in a VFR machine, without an IF procedure, below LSA/MSA is gonna save Your arse in Mountain soup.....you'll end up like this gung-ho Pilot this sad thread is about :}

Stay up right & stay within limits :cool:

This thread probably needs to be split into two: the discussion about this incident and operations in VFR; and, another on the important issue of why the scan of a helicopter pilot differs from that of his fixed-wing cousin.

In a recent RAeS presentation of eye-scanning, it was shown that some helicopter pilots (both experienced and not-so-experienced) were not using the AH as the fulcrum of their scan for flight in IMC. It is important to see this not as a fault on their part but as an issue that needs to be understood.

Jim

"Please correct me if I'm wrong; the AH is not a required instrument legally for DayVFR?"

Not under operational rules in Europe or Canada, but there may be engineering rules that require it - a 212 guy got caught out by that in Canada.

Phil

Jim, some of that might be due to the prevalence of glass cockpits, since the old selective radial scan, where you had to move your head to encompass all the analogue instrument scattered across the cockpit, can now be replaced by a 'big picture' type scan where the PFD only requires a fixed gaze at the attitude with the remainder being picked up on peripheral vision.

Hi Crab,

Yes, that is correct but the 'heat maps' provided by the eye-tracking system did not even include the horizon for some of the pilots. There must be a reason, and that reason should be understood because it might require an adjustment in the configuration of the screen or more education on the the optimum scanning pattern (do we educate pilots on the necessary scanning pattern for glass screens? do we specify, precisely, what should be monitored by the PF or the PM when hand flying? Is there an optimum distribution of the monitoring duties of each of the pilots when the autopilot is engaged?) All questions that should not go unanswered.

The comment was made at the conference that if neither pilot included the horizon within the scan, a critical departure from the flight path could occur and might be missed.

If there is a difference in the required scanning patterns between a stable fixed-wing and an unstable helicopter, what does that imply?

Jim

One of the classic student mistakes in IF is 'instrument chasing' where any one or two instruments are concentrated on to the detriment of the AI - it is obvious to the instructor and will inevitably end up with inaccuracies or unusual attitudes as the task gets more demanding.

A good instrument pilot will base his scan around the AI but we all get lazy sometimes, especially when the workload and arousal levels are low.

When things get gnarly then it is those with the AI centered scan who will retain accuracy and safety and the instrument chasers will probably scare themselves.

Despite VF's dismissal of its value, the use of the AI for mountain flying has long been taught in the UK mil - perhaps because the skills learned from a visual/IF balance are even more important when you fly the mountains at night.

Hey Crab.....I hear You Mate, I'm not negating the value of an AH, for IMC & for NVMC it is a life saving necessity. Wouldn't leave home without it!!! :ok:

For DayVMC under VFR in the Mountains it is a distraction from looking outside if Pilots wanna be chasing it & in these unique conditions eyes outside is where You wanna be, to stay safe ;)

Heaven forbid, I'd never wanna be up in these Mountains at night :O

Happy Landings :)

VF - surely you must scan the AI from time to time even when you are VMC, because there must be a lot of the time you dont have a natural horizon in your environment? (In that a level horizon is rarely visible unless you are above all that massive terrain)

Agree, but surely 'move your head' is a typing error. Instrument scan should be eye movements only whether radial or orbital, head moves can start vestibular canal upsets; the occasional glance over to Ts & Ps on a large cockpit panel should be the only conscious head movement.

Going way OT here from the OP.

I've had that happen to me a few times. I couldn't take off because of unforecast early morning fog. I was castigated for not informing the passenger the flight would be cancelled, the night before.

I've also been called a "jobsworth" to my face when insisting I stuck to the regulations when using a private landing site (no ops after dark, the passenger wanted to come back well after last light).

And I've been called a "chicken" by the owner of a listed building when I decided not to land in his confined area of a garden because it was downwind in 25-30 kts of wind. Flying into wind to land to get in there would have involved very low flight over his house roof and would probably have lifted tiles or worse.

You do need broad shoulders for this job.

Or thick skin!

You could do that on a Gazelle but the Wessex, Lynx and Sea King all required some head movement to scan the instruments, especially if you were on standbys.

Preferably both!

Really? The basic T is essentially the same in all of them and eye movement did it for me, although I didn't experience the Lynx. Even my later life with graduated lenses didn't require any head movement for analogue instrument scan in many different civilian types. The standby AH in the Sea King is almost touching the main AH, and when on the HAS1 I 'pioneered' the adjusting of the engine instruments so that when in normal operating range the needles were all vertical and easily checked. Anyway, that's what the left hand seat is for, isn't it?

We'll have to agree to disagree.

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But we do agree that the AH is a primary instrument for IFR :ok:

And to think this was the typical IMC panel of yesteryear.

Someone mention limited panel?

Hey Non-PC Plod.....Brother the DayVFR machines have no requirement to have the AH serviced to an IF standard, they topple often & are just not reliable. I wouldn't trust them. As SuperF mentioned many NZ machines have no AH & fly in the Mountains! Rarely am I above the massive terrain so the technique I was taught by Grand Master Mountain Pilots is that Your attitude is determined by Your Airspeed which is based on the stick position, I was taught You don't look at the horizon to determine speed nor attitude, wouldn't work very well here surrounded by these hills anyways, only the IAS. So You could say my AH is actually my IAS :) this method has been working fine thus far :ok:

AH sure is the primary instrument for IFR & NVFR = YES :)

Cheers it's beer o'clock

VF - the problem I have with that technique is that your attitude will tell you what is about to happen to the speed whereas the IAS only tells you where it is at that moment in time.

You must end up constantly chasing speed with cyclic movement, especially in gusty conditions.

Attitude for airspeed, lever for height:)

John - I think you might have moved your head a bit more than you think - its not a lot, and not enough to cause vestibular issues, but I think it is unlikely that your head remained absolutely still during your scan.:ok:

G'day Crab........really I don't have a problem with this technique & Mountain Pilots I know also don't, it works. I am not chasing an airspeed. The stick is fixed to the side of the thigh & politely holds the airspeed exactly where I want it leaving most of my time with eyes outside rather than staring at the AH which in this part of the World not maintained so cannot be relied on? :)

Cheers

Who nicked the GPS on that old instruments panel?

Charles himselve after landing at Le Bourget.

Cheers SLB

In the way of War Stories....re instrument flying in helicopters I have this to offer.

As part of my US Army Helicopter Instrument flying course at that wonderful Alabama Resort area known as Fort Rucker....using Huey's....we at some point had to enjoy a flight into Knox Heliport by executing an NDB Approach with overhead Hold.

Piece of cake right.....No Gyros, Fixed Card, unstablized single engine helicopter with no RadAlt.

That it was in IMC proved to me my Instructor was near suicidal and had real intent to take two others with him in the process.

That it was I doing the flying....is what convinced me of that.

Artificial Horizons are very nice kit...and have their uses....but they in my definition (if not in the usual context/definition) are "Secondary" instruments.

I am of the school.....that a single Attitude Indicator is a necessity but a Backup is pure Gold should the first one lay down on you while in IMC conditions.

A test I used while Instructing Instrument Flight.....was to use Unusual Attitude Recovery Exercises to determine what technique the Trainee used for controlling the aircraft.

I did the usual, Head down, Eyes Closed, wiggle the sticks all about and add some varying kinds of G Loads.....but that was just to disguise my setting a Five Degree wing low attitude on the Student's Attitude Indicator without being seen.

Then I gave control back while in a very minor non-level, out of yaw trim condition and sat back and observed the recovery to level flight.....and in some cases could have run out fuel waiting for that to happen.

Some Pilots very quickly sorted out the Attitude Indicator was out of whack as they were flying the other instruments and using the AI as a Reference. They would set wings level, pitch attitude level....and then correct for the resulting variation and in a cycle or two....perhaps three...sorted it out.

Others....as mentioned NEVER would have gotten settled down.

As to moving one's Noggin about while "Scanning"....in the scenario above....looking at the Standby...and other Pilot's AI worked well too.

Just looking at two AI's....each showing something different...does not immediately tell you which one is the liar.

In some of the Accident Reports we read about now and then where airliners smack the ground at warp speed because of a loss of control due to instrument failure...it makes you wonder why the crew with at least three AI's could not sort out the problem very quickly.

SAS;

I spent most of my early career two crew, there was a natural tendency to turn slightly towards your colleague when everything was relaxed. It was brought home to me by a very senior training captain when he pointed out that I had just flown 80% of a solid IFR trip looking at his instruments. I had never noticed that habit forming.

A few weeks later I had an FD failure on my side which took some time to notice because my attention was on the other side. Now I fly a mix of single and multi crew, and age has set in, but I very much agree with you, while the AI has the primary function, if you don't have speed and altitude nailed the AI can be letting you down very subtly and steering you to a whole can of worms.

SND