Question for commercial or high hour IMC private pilots

[piperboy84]

How do you feel about flying heavy IMC with a single attitude source . I.e. No dual vacuum pumps or backup AI, I understand you may have done it earlier in your flying career or while training, but would you do it now, and if so are you comfortable doing it.

[Mach Jump]

...heavy IMC...

What do you mean by 'heavy IMC'?

I'm still happy flying IMC with a single vacuum AI, so long I also have electric T/S or T/C.


MJ:ok:

[Andrewgr2]

Limited panel recovery from unusual attitudes with no AI or DI has been part of every IMC rating renewal I have ever done. I wouldn't want to fly on limited panel for long but could, I hope, manage to get out of the IMC. If by 'heavy IMC'' the OP means conditions down to IR minimums, I don't think I would want to be there in the average light single in the first place.

[dirkdj]

Having a T/S or T/C is a must, I would prefer to have a second altimeter before a second horizon; once, on IMC departure, I had my primary altimeter freeze at 500ft while climbing at 1000fpm IMC; second altimeter saved the day.

You need to practice partial panel from time to time, even on a simulator is better than nothing. It is best to have some device to cover the offending horizon because flying in real IMC with a failing and tilting horizon is disturbing.

[Genghis the Engineer]

It's all about currency

If I am current, then going to partial panel for a bit is manageable. If I'm not, then I don't want to be flying IMC at-all.

G

[A and C]

Flying IMC with only one attitude source is an accident about to happen...... It's just a question of how long before a technical failure results in a loss of control.

As for flight with only the TC, I was quite surprised how well a student go mine performed when during training the vac pump failed, the controler reverted to no gyro procedures and the student piloted the aircraft to minima on a PAR.

The student was at the end of his IMC course and was an above average student but it proved that even a low time pilot can if he uses the correct technique fly safely after a major failure of the attitude system.

[Pace]

PiperBoy

You are a good IMC pilot when it takes so little effort to fly IMC in cloud that you can fly instruments while thinking about what you are going to be doing with the wife and family at the weekend or where your tension levels are the same in or out of cloud.

You should be so comfortable flying instruments that it takes up so little of your brain power to do so that you can multi task in the cockpit.
at that point a failure of anything is easier to deal with than if your IMC flying starts as a tense situation requiring a lot of effort at best of times and any failure or problem then builds on that tense background to your IMC flying

As for Hard IMC do you mean cloud bases at or near the minima for an instrument approach ? The fact that you do not get on top for the whole duration or that you are challenged by weather while flying in IMC?

Pace

[Genghis the Engineer]

You are a good IMC pilot when it takes so little effort to fly IMC in cloud that you can fly instruments while thinking about what you are going to be doing with the wife and family at the weekend or where your tension levels are the same in or out of cloud.

In which case, I am not a good IMC pilot!

G

[Johnm]

It's all about currency and practice. I'm pretty rusty at the present so flying partial panel would be no picnic. However in training you have to faff about with compass watch and TC, in the real world you'll usually have a GPS for heading and track which makes life much easier.

So you can use the turn coordinator for keeping the wings in the right attitude, the altimeter and VSI for pitch and the GPS for heading/track which isn't too hard.

[OpenCirrus619]

It depends on the situation and who is with me...

I regularly used to take "Cloud Climbs" in my glider, which only had one gyro instrument - an electric T&S. However:

I was entering the base of a cloud - so I knew cloud base was well clear of the ground
The glider had truly speed limiting airbrakes (i.e. speed limiting in vertical dive)
I always had the option to spin it (thus avoiding Vne) and recover once clear of cloud (see first point)


In a single engine powered aircraft it depends...

First question is whether the aircraft can be handled in such a way that it won't exceed Vne in the event of loss of all the gyros. For example a Cessna 182 can be configured to fly hands off in a stable descending turn.

Second question is "Who is with me?". If I have passengers my envelope shrinks.

Third question is "How high is cloud base?".

Basically, taking the above into account, I will go IMC with only one operating gyro provided there is high probability of walking away if it fails (not saying the aircraft will be in a fit state for the next punter however).

This thread does, however, remind me of a time (when much less experienced) that I flew back from Cumbernauld to Denham - the first couple of hours (after climbing through a hole) were "VFR on top". When I got back someone indicated they thought this somewhat foolhardy - as there were definitely examples of "embedded towering cumulo granitus", which I would surely have found had the engine stopped. That thought had never occurred to me - lesson learned.

OC619

[Curlytips]

Happy to fly with single "official" source, but have surprisingly good back - up with Garmin 496.

The instrument page gives all you need to continue, as long as you remember that everything is GPS - derived, particularly height.

Important point is before you commence flight you need to have it turned on and programmed with route, and then scroll through each page, accepting info by "enter" on instrument page and terrain page. You don't want to have to start scrolling and accepting after the vacuum falls over and you are in the midst of weather.

[foxmoth]

Actually many people find limited panel easier than full panel - less to scan. I think the question here is more about flying with only one SOURCE for the instruments, the problem being of course that if that source fails you have little left.

[piperboy84]

Curly tips

Here's an interesting article about using the 496 ( I have a panel mounted one in my plane) as a "six pack" written with the guy designed the software for garmin

http://www.pinellaspilots.org/files/garmin-sixpack.pdf

Foxmouth, the one source issue is what I was referring to, I just think that I have too much reliance on one pump and one AI and would hate to attempt or be forced to fly partial panel getting tossed around in a cell, I figure my life is worth me splurging on this RCA 2600-3 SERIES DIGITAL ATTITUDE GYROS from Aircraft Spruce (http://www.aircraftspruce.com/pages/in/rcallen_attitude/rca2600-3.php)

And as soon as UK customs get done raping me on the import duties it will be installed on the plane, it's lightweight , solid state, and I,m putting a battery backup on it. Overkill perhaps , but if it helps me in a squeeze it's worth it

[foxmoth]

Depends a bit what you mean by partial panel - normally you have one source for AI and a different one for turn indicator. Failure of one system thus leaves you with a decent roll indication and should be no great problem for someone trained and current, as I say, many find it easier as you have less of a scan to do and in training you often find student fly better on limited panel than full because of it. Single source, as can happen on home built scan mean you lose ALL basic roll indications, that really makes life difficult, and I would not fancy that in real life!:eek:

[Curlytips]

Piperboy

Great article about the Garmin. Never seen before but confirms everything I self - taught. Will read again a few times!

My 496 sits on the yoke mount with remote antenna sat under middle of windscreen - has never gone offline.

[Big Pistons Forever]

The problem with real world one vacuum pump IMC is that when the pump fails the gyro starts to wind down which then causes it to gently roll over with you of course initially following it.

This means that you first indication something is wrong is when the there is disagreement between the instruments which will initially cause confusion and by then you are almost certainly in a unusual attitude which means you first action will have to be an unusual attitude recovery

I had this scenario happen in IMC on a bumpy day in a C 172. The fact that this airplane was so forgiving made the outcome OK but the initial transition was very ugly and I am convinced if I had been in a High performance SEP I probably would not have survived.

The take away for me was that all the partial panel training I did in no way prepared me for the shock and mental confusion of instruments not agreeing.

From that day on I have never flown an aircraft that did not have dual vacuum pumps in actual IMC. The best set up IMO is a dual vacuum pump set up plus a standby electric AI

[thing]

I've had an AI and DI go tits in IMC. Vac pump went on strike and the AI toppled. Not a great problem really but I practise a lot. If I'm off somewhere with a mate in vmc and I'm flying a leg I'll get him to be safety lookout while I go head down for twenty minutes or so. I enjoy flying on instruments (I know, weird).

The worst scenario is to have an AI that isn't erecting as fast as it should and not noticing that the TC and AI are telling different stories. I've had that a few times, get level on the AI and wonder why you're slowly turning.

[piperarcher]

I might also suggest using the autopilot on a basic wings level mode for a while (so long as you can trust it and you know it's in good working order).

I fly a IFR equipped PA28 with no backup equipment (except the GNS430 for navigation purposes), but if I had an AI failure in IMC I'd be keen to get out of it ASAP. It's OK to use the DI and the Altimeter for straight and level, but trying to chase the VSI is something I think you have to avoid doing, and in my opinion using the T/C for long periods of time is a recipe for disaster (though actually maybe the longer you spend getting used to it in IMC the better you will cope with it's waywardness).

I have had an AI go before, and a DI, though not together, and not in IMC luckily, so I am a little sceptical about any kind of hard IMC. Plus my total IMC hours over 7 or 8 years is not particularly high and I tend to fly IMC when there is a relatively high cloud base to be on the safe side.

[Big Pistons Forever]

I might also suggest using the autopilot on a basic wings level mode for a while (so long as you can trust it and you know it's in good working order).

.

This is good advice if you have a basic wing leveler single axis autopilot which gets its information from the turn coordinator. More advanced autopilots get their information from the AI so turning it on if the AI fails is just going to make matters worse.

[sharpend]

Well all I can say is that in the very dim and distant past, when Pontious was a pilot, we taught IF in Chipmunks. That meant, on a dark and dismal Yorkshire November day, we climbed above cloud (base 600 ft) and taught IF straight & level. Then we did 5 minutes of aeros to replace the boredom (remember most of us QFIs were not long off big boy fast jets). Then were recovered back to base (still a 600 ft cloud base) with no PAR/GCA, Sat Nav or ILS, just an old ACR7 approach. No attitude indicator either as we did not have any spare time to fly straight and level for ages to allow the AI to erect. So T/S and a DI only with a fair bit of icing to think about.

An accident waiting to happen? Never.

[Genghis the Engineer]

And you'd have let your students, or an equivalent civvie PPL to do it? Or just current military QFIs / Qualified Service Pilots ?

G

[Johnm]

I've had a few bits of light entertainment with equipment failure in IMC. I had the pitot static freeze up a couple of times, but with working vacuum and electric systems and power indications it's not a big problem.

I once had the AI fail on a PA 28 and then made the mistake of engaging the autopilot...."..:eek:

[Andrewgr2]

For the benefit of those of us to have lived sheltered lives, can someone explain what an ACR7 approach is? Googling didn't provide much help although I infer it is some sort of radar approach.

[Pom pom]

A talk down approach with a stepped down glidepath.;)

[BEagle]

As sharpend wrote earlier, IF was indeed taught in the venerable Chipmunk and I was one of those who received such training in the early '70s when I trained for my Preliminary Instrument Flying Grading (PIFG) at University Air Squadron. The main difference between PIFG training and IMCR training was that the RAF concentrated on sound basic IF skills, whether on full or limited panel. Unusual attitudes (we termed them Unusual Positions) were considerably more demanding than any civil IR requires - the reason being that a student could get find himself falling out of some aerobatic manoeuvre and suddenly in IMC. The AH would often topple, so the Turn and Slip was invariably used for UP recovery and it was essential to cage the DI before deliberate UP training. Once back in straight and level flight, re-synching the DI to the wet compass wasn't that easy as the compass had to be carefully reset (it was on the cockpit floor in front of the control column) whilst maintaining S&L flight - then reset and uncage the DI.

The only radio aid we had was a single 10-channel VHF set. So maintaining a mental picture of where you were whilst being vectored around by ATC became a core skill. Approaches were limited to PAR, SRA or, if you were very unlucky and there was no nearby ATC radar unit, VDF.

25 years later I taught basic IF in the Bulldog. Initially it was much the same as it had been in the Chipmunk, but the gyro instruments were a little better. Again, until the early 1990s we only had a basic crystal UHF radio with about 10 channels at best, but we also had a standby 118-136 MHz VHF set. Then came a very welcome mod. which provided VOR/DME, ILS and a full 225-400 MHz UHF - and even a transponder! No longer did I have to rely on UDF and VDF cross-cuts to know where I was above 8/8 cloud! The VOR/DME was really only used as a fixing aid, but I also taught students VOR tracking and VOR/DME holding. I developed a basic radio navex which my students flew dual; if I was happy with their performance, I would then send them off to do the same thing solo. One day I sent off one of my girls to fly the route above 8/8 cloud, then back for a PAR as the cloud base was within her limits. My more conservative colleagues were surprised that I'd authorised her to fly the exercise, but when she came back she said that it had been good to do something more challenging than yet more aerobatics in the local playpen and how good it felt to have been trusted in such a way.

To my mind, far too much IMCR training seems geared towards playing airliners in spamcans rather than acquiring sound core IF skills. Although I do recall one UAS student who, it seems, hadn't done much 'actual' IF work, most had been under a visor. It was obvious that he was cheating during UP recoveries, so I found some nice solid cloud and forced the little bugger to apply the techniques correctly - he did so and his general IF improved as a result.

There was some reluctance by my QFI colleagues to fly aeros or formation tailchasing above 8/8 in case the AH toppled. Bunch of wimps! Why did they think we were required to fly limited panel let downs as part of the annual IRT?

Even EASA has woken up to the fact that many current people-tube minders cannot seem to cope with unusual attitude recoveries these days even in VMC. So consideration is now being given to greater emphasis on training for such events at an early stage of flying training......

....as the RAF has always done!

[flyme273]

It seems to me the key points of the question are "comfortable" and "heavy IMC" - whatever that means - I assume a planned flight in continuous IMC, not just a chance encounter with a pop-up cloud or transit through a cloud layer.

For myself (being a coward, maybe a bit rusty on IR flying and not wishing to scare myself), some form of auto camel would be appreciated (this could take the form of a second crew member).

Once camel is engaged, charts can be conveniently read, frequencies changed and new plans made without the risk of loss of control.

Of course one would then need to know the input requirements of the auto camel. This maybe independent or the (failed) Attitude Indicator (in which case it's not much good) or if a simple wing-leveler it is normally the (electric) TC. Nav inputs from Garmin would also be helpful, assuming the heading bug on the DI has failed. I'm not sure if VOR tracking would be available, does this use the DI?.

As far as limited panel goes, much depends on the instruments in the particular aircraft, these can be well damped or rather wobbly. I would tend to regard limited panel as survival mode only.

To summarise, we need to know the aircraft fit-up and if electric/ vacuum driven (this can vary), then the "comfort" of continuing or recognising a potential "survival mode" can be determined and appropriate changes to the flight plan made (call for help).

An interesting question for the average light aircraft.

flyme.

[sharpend]

Of course today is very much different to the 60s. Then we had no MOT, no calculators, no Sat Nav, no breathalizer etc etc. Today is different. Health & safety & political correctiveness rule alongside the accountant.

I remember Bruce Latten sharpening up my steeps turns (60 degrees of bank) in a Folland Gnat over the Irish Sea. On instruments at 50 feet above the waves! After that I did not lose 50 feet in a turn! That set me up subsequently for programming the NavWass in a Jaguar at 540 knots, 250 feet AGL.

I also remember low level night navigation exercises in the Chippy! No map reading possible at night over the North York Moors so it was the veritable true bearings that fixed us. Not always possible at 500 ft agl.

We were mad! Silly billies.