experienced first mechanical failure today on 5th lesson

[ShyTorque]

Why would a glider be in IMC?

If it's no big deal for a glider to enter IMC with no attitude indication, please tell me how they do that sir because it blows my mind...

Did anyone actually say they did?

[jxk]

When I did my IMC rating I was shown how to fly on just the compass and Rev Counter - keep the compass needle steady and watch the revs, less revs climbing, more revs descending. However, this was in a Cessna 150 (fixed pitch prop) and quite a few years ago - thank you Ron Hayter!
It's sounds as if the original problem was with the suction gauge itself and not the vacuum pump. Although, vac pumps as someone has already stated, do have a limited life and may have influenced the decision to change it. It's not likely that the problem was in the engine bay but at the back of the instrument panel.

[MarkR1981]

My two pence worth.


If gyros were lost/suspected lost whilst already airborne in VFR conditions= no great panic just be sure to stay VFR and possibly return to the airfield ASAP depending on Wx etc.

If gyros not working/suspected not working prior to leaving the ground any sensible individual would turn around and investigate. Teaching students to take a casual attitude to these types of things is not professional.

A pain in the ass- Yes- but better to take that attitude than the one that may eventually lead to your unecessary demise

[ShyTorque]

Surely I'm not the only one to have been taught to fly using aircraft external attitude/visual picture, not by looking at an AI, and using a "bubble" compass, not a DI?

Our training involved recovery from UPs during instrument flying (not just mild upsets, but full aerobatic manoeuvres) using the turn and slip, altimeter and ASI.

Having said that, there is no way I would depart into IMC, or when there was a risk of having to fly IMC. But flying with no AI or DI in good VMC? Why not; that's standard fit for some aircraft.

btw, I've been round long enough not to do "casual attitude" with regard to flying. I make a decison based on risk assessment and knowledge of the aircraft systems, the weather, my own ability and legal requirements pertaining.

[IO540]

When I did my IMC rating I was shown how to fly on just the compass and Rev Counter - keep the compass needle steady and watch the revs, less revs climbing, more revs descending.

That works in very smooth conditions, if you really stay on the ball. Once you "lose it" a bit, that's it, game over. It's OK for emergency climbs or descents through a layer of cloud. Descents work better because most planes are more roll-stable when descending.

The other reason I would not fly with duff vacuum is that one never quite knows what the problem is.

It could even be a "little problem" in the accessory drive gearbox, where the vac pump is driven off. Unlikely but not impossible. I once had a similar "little problem" in a car, and by the time I got home, some 30 miles down the road, the whole gearbox was shredded. The accessory drive box also drives the camshaft, and the mags, so it is relatively important

A seized vac pump (less unlikely than the above) is supposed to snap off its drive shaft and thus protecting the engine from damage, so that's not so bad, but only an idiot would then do a discretionary flight. One would certainly want to investigate.

[pitofrost]

"Why would a glider be in IMC?"

Because the pilot's a loon chasing records flying inside a cu-nim or inside a cloud street.

It used to happen a lot more than it does now. Not that I'd go anywhere near...

[NutLoose]

One should read

http://www.caa.co.uk/docs/33/AIRCOM200905.pdf

mind you as not all aircraft flying VFR have vac pumps, I can see why an aircraft that has flown past this life could be placarded VFR operations only until the pump is replaced. Remember this is type specific, the later pumps with wear indicators have different lives, hence I now install those upon replacement.

BUT

Totally agree with IO540, this is driven off the engine, so needs at least checking that it is the drive coupling that has sheared as it is supposed to and not engine internal failure, before it is ferried VFR to get replaced... because that will kill you..... those gears as said drive the oil pumps, mags, cams and last but not least the vac pump!

[ShyTorque]

As usual, the thread has gone off at a tangent.

The OP said that the vacuum powered instruments were actually working!

So the pump itself was working. The only unserviceability was the vacuum gauge. Possibly because the "feed" pipework to it had not been connected properly. Again, this was reportedly a VFR only flight.

[NutLoose]

Actually Shytorque he said

it appeared that the attitude indicator and DG were working

as the vacuum gauge is actually in the system and normally plumbed across the AH or similar, a zero reading on it can indicate a system leak of which they have no idea how bad, which then means the Gyro in the AH may not be spinning fully up, this can result in the AH starting to topple and give a false reading, it may appear to be erect on the power runs and for some time afterwards until it slows down........... but as said it was VFR flight...

I know of one aircraft that killed the crew following a slowly toppling AH (none VFR) which they followed on take off to the crash site.

[Plasmech]

I know of one aircraft that killed the crew following a slowly toppling AH (none VFR) which they followed on take off to the crash site.

I wonder how on earth the investigators figured out that's what happening, assuming there was no FDR/CVR.

I guess they found a the mechanical faults, looked at detailed weather records, maybe a radar track, and put two and two together.

As usual, the thread has gone off at a tangent.

The OP said that the vacuum powered instruments were actually working!

So the pump itself was working. The only unserviceability was the vacuum gauge. Possibly because the "feed" pipework to it had not been connected properly. Again, this was reportedly a VFR only flight.

I think that maybe my point was that the seemingly faulty gauge thing was downplayed a bit too much by the instructor.

I think there are at least two different types of flying:

1. Hobby flying, what I am going to do when I get my liscense. I am not on a schedule, have no actual mission, a liver transplant patient is not going to die if I don't get there, and passengers aren't going to riot at the gate because they are stuck there for 8 hours. In this type of flying, for me personally, I see no reason whatsoever to fly an aircraft that is anything less than 100%.

2. The other type of flying, see above.

Now, this is not to say that if I was a commercial pilot I would just brush off bad instrumentation, but rather I would follow the MEL to a "T", and that MEL might let me fly on a bad vacuum gauge, I'm not sure. Granted if we are scaling this up to a commercial flight, it might go beyond a piston-powered vacuum gauge, but the general concept is still the same.

[ShyTorque]

The rules for commercial flights, i.e. "public transport" as they are known in Euroland, are much tighter, and for good reason. Such a flight is likely to be required to go IFR/IMC. The aircraft therefore also needs more equipment and the pilot needs to be instrument trained/qualified.

But your flight wasn't public transport and for an early syllabus VFR training flight you didn't need the instruments that might have been affected had the entire system failed (and it obviously hadn't).

For VFR this side of the pond you only need a radio, in order to operate in controlled airspace.

What personal rules you choose to put in place later, if stricter than the legalities, are an individual thing.

[Piper.Classique]

Surely I'm not the only one to have been taught to fly using aircraft external attitude/visual picture, not by looking at an AI, and using a "bubble" compass, not a DI?

No, you aren't. And I have done cloud flying in gliders to get up (big cu), and to get down when the wave gap closed. Legal in some countries, and done on a somewhat de-sensitised turn and slip, magnetic compass, and sometimes a level bubble. Needle, ball, airspeed. Needle, ball, airspeed. needle, ball, airspeed, altimeter. needle, ball, airspeed, all done listening to the vario and probably working out a departure heading if it's a climb. Descents are usually in a straight(ish) line. Nowadays we use gps as well, makes the navigation easier.

I normally fly power on a basic panel, no DI or horizon, but VFR. This absolutely should not be a problem. The big horizon is outside the windows, and is also where the other aeroplanes are.

However, the original post was more about what should be serviceable on departure, and despite Plasmech's somewhat forthright attitude for a sprog, he does have a point about the apparently rather casual approach shown to maintenance on his training aircraft. Is his instructor reading this forum, I wonder?

[SNS3Guppy]

The OP said that the vacuum powered instruments were actually working!

So the pump itself was working. The only unserviceability was the vacuum gauge. Possibly because the "feed" pipework to it had not been connected properly.

Interesting observation. Are you a mechanic? I am (what you might call an "engineer'). I certainly couldn't make that diagnosis based on what's given, even with a mechanical background, being a flight instructor, and having a fairly intimate knowledge of the systems involved. Not enough information is provided.

To suggest that the only problem was the gauge, is in error and inaccurate. Given the source for the instrument indications at fault, one must by default assume that the instruments are unreliable,and discount them.

Many have followed the insidious slow wind-down of a gyro to their grave.

Given that much of the flight training today is done on an "integrated" basis, combining reference to instruments with visual training, and that training in turn translates to instrument training later on, developing poor habits (or giving poor counsel that leads to bad habits) at this developmental stage is grossly inappropriate.

[FlyingKiwi_73]

The only 'thing' i have flown with when INOP was the landing light.

I got in on of the schools tommies and noticed an lower than normal oil pressure, it was mid yellow. i refused to take the A/C and watied for the other to be availble, took some stick for it. Nothign happened to the A/C no smoking hole etc... but i felt happier waiting for another A/C than going out (early Solo) with engine parametetrs i was not totally happy with.

I also flew (with an instructor) an A/C with a new engine just out of maint. We had to keep the rev's up so everything was hurried (get to hold point, don't do proper run-nup, don't do low idle,take off, keep temps green etc) what we didn't do was REALLY take our time with the inspection on the ground. after the flight we found a flashlight in the engine bay and a screwdriver in the cockpit!!!!!!!!!!!!

That will be one of the most important lessons i've ever had.

Never rush a preflight! and if you aren't happy with the plane say so. you may even get a bit of respect for doing it.

[ShyTorque]

SNS3Guppy, you are a self declared know it all on most things. Firefighter, Jumbo pilot, mechanic, engineer, flight instructor and systems expert.

The instruments wound up on engine start and stayed erect. Read the information put up by the OP.

Many have followed the insidious slow wind-down of a gyro to their grave.

In VMC, as per this flight? Codswallop, or poor training.

Developing poor habits? Looking out of the window under VFR and flying using aircraft attitude against the outside horizon, rather than the AI, is a poor habit? So perhaps this is this why you previously told folks they must avoid coming near "your" airspace, wherever it is. You have said before that you care nor know what sort of airspace it is or what the rules say about maximum IAS. You said you might be at 300 kts, in VMC in Class G, on an IFR flight in a heavy jet. So you're not looking out in VMC? Maybe you should stick to the mechanicking.

[NutLoose]

Oddly enough this guy was out flying VFR..........
no doubt it would never happen to you

http://www.alexisparkinn.com/photoga...ightassist.mp3

sobering listening

I wonder how on earth the investigators figured out that's what happening, assuming there was no FDR/CVR.

If I remember correctly the impact crushed the AH at its last indication.

[Big Pistons Forever]

My 02 cents, from the point of view of an instructor teaching a presolo PPL.

Presolo: I direct the student that they do not need to look at the AI as they will observe the attitude of the aircraft by observing the horizon when looking out the winshield. Similarly they will determine the direction of the aircraft by visual observation of ground features and with the use of the map. I tell them I will introduce the use of the AI/DI after solo.

However checking the suction guage is part of the runup. When the student observed the zero indication on the guage I would direct them to return to the ramp and help them write up the snag on the log book. Even though we will not be using the air driven gyro instruments I do not think it is a good idea to encourage very new pilots to deliberately decide to fly aircraft with inoperative fitted systems. Instead, enginering assistance will be engaged and the aircaft inspected to ensure no unsafe condition exists (eg the pump has come loose) the suction system properly tagged as unservicable, and a defered maintainance entry be made in the aircraft log book. If this can be done with little delay the flight might be continued, and some valuable training in discovering and dealing with aircraft defects will have occured.

[IO540]

If I remember correctly the impact crushed the AH at its last indication.

I wonder how they could be sure... obviously they cannot be.

If you find a mechanical watch on someone's body, you can be fairly sure the watch did not move since the impact, because in a purely mechanical watch the hands are held in place pretty firmly by a gear train which is impossible to drive backwards. But the mechanism of an AI (I am happy to send somebody the maintenance manual for a KI-256 ) is a wholly free mechanism which flops around freely.

For the same reasons, you can determine the pre-crash elevator trim setting (because it is a jackscrew) but you cannot determine (reliably) the throttle and mixture settings because they are free to move anytime.

[SNS3Guppy]

SNS3Guppy, you are a self declared know it all on most things.

That would be a lie on your part, wouldn't it? Find a single occasion when I have ever said any such thing. Perhaps your lack of experience would lead you to believe that.

Firefighter, Jumbo pilot, mechanic, engineer, flight instructor and systems expert.

Considerable firefighting experience, yes. Aerial firefighting in single engine and multi engine aircraft, ground fire experience in structural, wildland, aircraft, and vehicle fires, as well as emergency medical and extrication. Absolutely. Yes, 747 experience. Yes, I'm a mechanic and have been for a long time, as well as an inspector, to boot. And check airman. A US mechanic is the same as your "engineer." I'm a flight instructor, and a ground instructor, and a flight engineer, and yes, I do understand aircraft systems fairly well. It's a job requirement, you see. Perhaps your background is military aviation, which would explain your limited experience or understanding, and perhaps even why a little experience and understanding seems fantastical to you. Does any of this matter? No, not really. Apparently it matters to you, though.

The instruments wound up on engine start and stayed erect.

Which means exactly squat, doesn't it?

The only indication of motive force for the gyros is the suction gauge. Too much suction or too little means an unreliable gyro. No indication means an unreliable gyro. Where do you find certification for the system to be operated without the gyro suction indicator? Where do you find mention of the supplemental type certificate, or a minimum equipment list, or configuration deviation list authorizing this particular combination of apparently-erect gyros, and inoperative or zero-indicating vacuum gauge? We don't find it mentioned, and you won't, will you? No such authorization exists.

You stated "So the pump itself was working. The only unserviceability was the vacuum gauge. Possibly because the "feed" pipework to it had not been connected properly. " This displays a gross misunderstanding of the systems, and a misunderstanding of systems knowledge. High or low vacuum pressure means an unreliable gyro. Low vacuum could be a source leak or a leak at any point in the system; at any instrument, at the filter, at the pump, at the gauge. High vacuum can be a blocked filter, kinked hose, or instrument problem at any point in the system. Either one means low or even no airflow through the isntruments; whether the instruments stand up or not means little; whether they appear to be erect is irrelevant. This doesn't imply reliability.

To teach a student to ignore these things, especially early in the training process, is very poor form on the part of the instructor. Pathetic, really. Any instructor worth his weight in salt would have taken the opportunity to teach how to do it right, and to teach about inoperative equipment.

Developing poor habits? Looking out of the window under VFR and flying using aircraft attitude against the outside horizon, rather than the AI, is a poor habit?

No, looking out at the horizon is a good habit. Stupidly providing a poor example as an instructor by taking a student aloft in an unairworthy airplane, and teaching that this is acceptable, is a poor habit. Giving the student an impression that it's okay to take off knowing that equipment is inoperative, to operate illegally, and to operate outside the airworthiness standards for the certification, maintenance, and operation of that aircraft, is indeed developing a poor habit.

You're not a flight instructor, are you?

So you're not looking out in VMC?

I have said nothing of the kind. I learned to fly in a J-3 cub that lacked radios, an electrical system or any of the gizmos in use today. You bet I'm looking out in VMC. IMC, too.

That's irrelevant to the subject of the vacuum gauge, of course. Perhaps you should stick to the subject, though you don't seem to know it very well. In your rush to smear, can you explain what looking out in VMC has to do with an inoperative vacuum gauge?

Do you understand the implications, particularly in a student environment, of inoperative equipment?

[NutLoose]

IO540 here is an example of what I mean

N2225A plane crash in CO details :: PlaneCrashMap

Controls and instruments were examined at the site and the following was documented.
Throttle full forward Propeller control mid range Mixture one and one half inches from full rich Fuel gauges both on zero Altimeter 6,280 feet (Kolsman reading obscured) VSI 1,800 feet up Artificial horizon 10 degrees nose down, 35 degrees left wing down (face crushed) Turn and bank ball full left, turn needle inverted 10 degrees left wing down. HSI heading bug on 225 degrees, course needle centered (face crushed), heading 190 degrees RMI 255 degrees Radio altimeter 0 Magnetos both Fuel flow 32.5 gph Manifold pressure 30.5 Hg RPM 550 rpm Landing gear handle up Flap handle position destroyed Battery on Alternator on Fuel pump on Landing light on Anti-collision light on Pitot heat off