experienced first mechanical failure today on 5th lesson

[Plasmech]

Nothing to write home about but...

Thought probability would dictate that my first failure of any kind would take more than 5 flights to happen.

During my run-up I found that the suction gauge was reading zero regardless of the engine RPM. Asked the instructor if we should go back to parking but he said it wasn't a big deal for a VRF flight, and apparently, on the ground, it appeared that the attitude indicator and DG were working. Turns out they worked for the entire flight, elthough I have no idea what the vacuum level was..if it was "in the green" or on the verge of not being enough.

On the way home I decided that had it been a night flight or a foggle flight, I would not have flown the condition.

It's probably just instrumentation (the suction gauge). Will ask next week after its fixed. Interestingly this 172 had its vacuum pump replaced yesterday. I thing the shop forgot about the whole "make sure it actually works" part.

Did I do right by allowing the flight to get off the ground? The instructor is the instructor but my butt is mine.

[RatherBeFlying]

For a day VFR flight, the suction gauge is not needed. However given that the vacuum pump was replaced, it looks like the hose leading to the suction gauge was left flopping in the engine compartment instead of connected to the new pump, but it's unlikely it would come to grief.

How well the vacuum pump tolerates unfiltered air is another question, but likely the cap for the suction gauge fitting was left on.

I would have shut down, opened the cowl and had a good look for anything else left dangling. After replacement of a component, a test flight or runup to verify proper operation and installation should be done. You and the instructor did the test flight:rolleyes:

[SNS3Guppy]

Instrument failure is insidious. The instruments may appear to work, but the assumption must always be made where the vacuum gauge is low or zero, that the instrument indications which use a vacuum source are not reliable.

The same may be true for high vacuum indications; this is usually the result of a blocked instrument air filter, and also suggests low gyro RPM, and an unreliable instrument indication.

Flying airplanes is all about dealing with abnormal and emergency situations; it's why we train, and it's wh we have procedures.

Vacuum pumps fail with some regularity; I've seen a lot of them fail shortly after installation. While wet pumps seldom fail, dry carbon-vane vacuum pumps often fail.

A good habit to get into with respect to maintenance issues is to ask to be shown what went wrong, each time you experience a problem. Any school worth their weight in wet salt will take the time to show you, and it's an excellent learning experience for you.

No pilot should be without an aircraft flight manual for the aircraft that he or she is flying. I've always strongly advocated that one obtain and read the aircraft maintenance manual, because it's got a lot more, and a lot better information than the pilot handbook.

[A and C]

Dry Vac pumps have a 600 hour life, most people who are opperating VFR seem to forget this and run the pump untill it fails.

The faiure of new Vac pumps is usualy due to FOD getting in to the system during fitting of the new pump.

[SNS3Guppy]

I've seen a few make 600 hours, and some go beyond, but I've seen a lot more not make it close.

[Fuji Abound]

I know of one which was still going strong after 1,600 hours. I insisted it was changed - I wonder how much longer it might have gone but was glad not to have found out.

[IO540]

Interestingly this 172 had its vacuum pump replaced yesterday.A potentially life threatening failure, straight out of maintenance. What a suprise (not)... Maybe they disconnected the pipe going to the gauge and forgot to put it back on. When you change a vac pump, you are also supposed to change some filters and some of those are behind the panel.

[Rod1]

Welcome to your first lesion on maintenance. Get a book, make a note and go back over them in 10 years. Chances are it will make interesting reading. You did the right thing flying provided the weather was good. There are 1000’s of machines flying with none of the vacuum instruments you had even installed. The important thing is that you assume they have all failed and preferably cover them up.

Rod1

[BigGrecian]

I'll throw out a different point of view :

FAR 91.7 (http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?c=ecfr&sid=df37be564789ddfe92ec76fd2a1b674b&rgn=div8&view=text&node=14:2.0.1.3.10.1.4.4&idno=14) states :

§ 91.7 Civil aircraft airworthiness.

(a) No person may operate a civil aircraft unless it is in an airworthy condition.

(b) The pilot in command of a civil aircraft is responsible for determining whether that aircraft is in condition for safe flight. The pilot in command shall discontinue the flight when unairworthy mechanical, electrical, or structural conditions occur.

My interpretation is that you should have returned to the ramp and had the aircraft looked at.

The aircraft would not necessarily be in an unsafe condition for flight but if equipment is inoperative then it is meant to be placarded as such and remarks entered in the aircraft logbooks.
It is irrelevant that many aircraft do not have suction systems etc - the law calls for appropriate action if it is fitted - and you would definitely have failed a practical test had you done that on the test.

This an all too common attitude amongst pilots - who to quote the FAA seem to have a too higher threshold to what should stop a flight

If you see more of this attitude I would start to question the professionalism of the staff / school.

[ShyTorque]

The flight was VFR and the pump was working.

The instructor decided the aircraft was airworthy, albeit not fully serviceable, so the flight could safely go ahead.

What would have been the consequences of subsequently failed suction instruments on a purely VFR flight? Not a lot.

I think the man who signed the tech log used his noddle and made the correct decision.

[IO540]

I agree the vac system is probably not legally needed for day VFR, but

The instructor decided the aircraft was airworthy, albeit not fully serviceable, so the flight could safely go ahead.

I sadly have to disagree with.

Most instructors haven't got a clue about airworthiness, and many schools collude with dodgy maintenance companies to minise costs. It is an endemic practice.

I started my PPL with a school which operated absolute crap planes despite having an AOC for charter work. During the preflight (on this particular type one opens up a part of the cowling) I found some bare wires which could touch something, cause a spark, and ignite any fuel leak. The instructor said it was OK. Some weeks later, with evidently nobody else noticing this, the said cable had come right out of of the connector. I refused to fly the plane. The instructor got a bit peeved off and said "it only goes to the landing light; just don't switch on the landing light". I took a walk to another school and chucked away 10-20hrs of training, plus some exam passes which got "lost". The school later featured in a celebrated accident in which the judge commented that if he could shut them down he would. No way would the CAA act, because they were paying them nice AOC fees.

The instructor is still there, still thumbing through the airline job adverts, a decade later. He is probably the CFI (gosh) now :) :) :)

So I would not take any instructor's word for the airworthiness of an aircraft. If it looks dodgy to somebody intelligent, it probably is.

And with no gyro instruments, if you enter IMC, you will plummet pretty fast. It's not smart.

[BigGrecian]

So I would not take any instructor's word for the airworthiness of an aircraft. If it looks dodgy to somebody intelligent, it probably is.

At Sun N' Fun the FAA do an airworthiness stand.

They have an aircraft which they have "made" unairworthy.

They get regular instructors/pilots and regular citizens to check the aircraft out.

The pilots do the worst. Regular citizens perform above a "trained" pilot. Go visit them at Sun and Fun!

so the flight could safely go ahead.

Maybe - but not legally in my opinion (From what we can gather the aircraft wasn't operated on an MEL)- and I'm 99% sure the Feds would agree with me...

So I would not take any instructor's word for the airworthiness of an aircraft. If it looks dodgy to somebody intelligent, it probably is.

I agree. The FAA also publish this on their website this as a common area of weakness by CFIs.

[Plasmech]

Oh I would never have simply brushed off a zero-vacuum reading on a checkride. Nor would I had I been doing a solo or a post-PPL flight. What happened is the instructor being in the plane made me feel safer. However, he shouldn't have. This was a mistake on my part. I learned a big lesson here: when my life is on the line, the decision is mine. I don't care if Chuck Yeager is in the right seat, if I say the aircraft is in a no-fly condition then, for my lesson at least, it's in a no-fly condition.

After the flight, I found out that this particular aircraft was, in a pinch, serviced by the field's only maintenance shop, and that the owner of the flight school hates this shop and 99.9% of the time uses a shop that's "a couple of airfield's" west that, according to my buddy that works for the flight school, has an outstanding service record and does impeccable work. The owner was pissed to see our squawk...NOT happy at all with the local shop.

What I didn't mention in my OP is that I decided that I did not like this particular instructor. He's not my regular CFI but rather someone I got when I scheduled a flight at the last minute to make up for one last weekend that got nuked by a low ceiling. I like to get in at least 2 a week. The reason I did not like him is because on take-off, we nearly departed the south side of runway 27. It was my first flight in a 172 (normally I use a 152) and I was not ready for the need for more right rudder during T/O roll. In a few short seconds, I was all the way at the extreme left edge of the runway. I believe my wheels actually left the ground at the very last milliseconds worth of asphalt...had I delayed rotation and longer we would have been in the grass. This could have been a real mess.

I kicked myself really hard last night for not getting on that rudder with more authority. However, I am not paying the guy in the right seat to just sit there and go for a ride. I didn't know my mere 5th lesson was going to essentially be a solo flight. While I'm sure I'll get some replies blaming me entirely for nearly wiping out on takeoff, I really think maybe the CFI should have gotten on that rudder to help me out. Has we crashed, I would hate to think I would be 100% liable for the cost of repairs or a new aircraft. I thought the CFI was the PIC but apparently not. Trial by fire I guess...

Well today I was back to my regular instructor. We did rectangular course, some navigation work, and I spent an hour wearing the foggles. Wind and turbulence were *intense* and incessant but I figure that makes for better training. So far most of my flights have been very bumpy as I train during the season change. I hope that when it comes time for me to do a solo, or rather a flight where the CFI stays on the ground in the case of yesterday's lesson, that the dang winds in this area finally calm down.

[IO540]

What happened is the instructor being in the plane made me feel safer. However, he shouldn't have. This was a mistake on my part. I learned a big lesson here: when my life is on the line, the decision is mineBest to not beat yourself up over this. Politically, it is very hard to go against an instructor. I used to go on training flights where the fuel situation was way below acceptable but I said to myself that if the engine stops I will fold my arms and let him do the forced landing (the flights were over loads of fields, usually) and his school can pay the £4k it costs to cart the thing out on a trailer and put it back together. Now I think that was not a good attitude, but it was OK at the time. I used to fill up "to the rim" before solo flights (in a C152, there was no ladder and no steps to get up to visually check) and used to get criticised for it, but so what?

and that the owner of the flight school hates this shop and 99.9% of the time uses a shop that's "a couple of airfield's" westGetting maintenance done "away" is a very common practice. It sidesteps all sorts of potential "airfield politics" issues. Unfortunately it also enables somebody to get dodgy (or nil) maintenance done, without rumours to that effect spreading locally...

As regards turbulence, it is often bad on hot summer days, unless you get above the white fluffy clouds. At this time of the year it is usually cured by flying higher. You are probably flying close to some terrain. Instrument flight is very hard in turbulence; you can't read the compass so are relying on the DI which may not be accurate, but fortunately one rarely flies on instruments at low levels when enroute. In the departure/approach phases, yes.

[ShyTorque]

And with no gyro instruments, if you enter IMC, you will plummet pretty fast. It's not smart.

IF you enter IMC? Gosh. So how do aircraft like gliders fly without them?

[thing]

? Turn and slip usually, AH if you're better equipped. Yes, I know the only legal requirement is to wear a parachute.

[Plasmech]

IF you enter IMC? Gosh. So how do aircraft like gliders fly without them?

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...

[Morrisman1]

Limited panel instrument time is taught for a reason, if you do have vac failure in IMC you have your VSI, ASI, altimeter and turn coordinator to reference. With these you dont really need an artificial horizon, its just a luxury

[Tinstaafl]

For the original poster: You're in the USA I gather so the aircraft was unairworthy. That's not to say that it's not possible to fly with a failed suction guage, but there are certain procedures that must be followed I.A.W. the FARs.

* IF it's operated with an MEL, then the procedure in the MEL for that failure must be followed.

* IF it doesn't have an MEL then you need to comply with FAR 91, part of which deals with failed equipment. The precis is that the failed item must be removed (mechanic's job) OR disabled & placarded unserviceable. Either way it must be noted in the aircraft's maintenance logbook.

[Jidi]

I remember that on one of my first cross country flights I also noticed the failure of the vacuum pump, meaning no gyros whatsoever. On the taxi way I told my instructor that we have 0 reading from the vacuum indicator .. he looked over my shoulder and said "yes, you're right. Well, if they could find Germany 70 years ago, at night, with only a compass and a map, I'm pretty sure we'll be able to find LRxx. At least you'll know how to do things if vacuum pump fails you in air during a cross country flight" :) So we went on and I was amazed how much I've learned about VFR navigation in that particular flight. I wouldn't worry so much for a local VFR flight without gyros. I even know some Diamonds Katana that are not even fitted with such.

[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? :eek:

[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. :hmm:

[NutLoose]

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

http://www.alexisparkinn.com/photogallery/Videos/flightassist.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 (http://www.planecrashmap.com/plane/co/N2225A)


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

[BackPacker]

The only thing that's missing, as far as I'm concerned, was the instructor placarding certain instruments U/S or INOP.

I've flown an aircraft with had a DI that was broken. Other vacuum instruments were allright. I simply tore a corner of my plog, stuck it between the instrument glass and the panel and wrote INOP over it. Saved me a lot of confusion looking at a spinning DI.

If placarding an instrument INOP is this simple, why would you take-off with a faulty (or suspected faulty) instrument and not placard it?

(Obviously this only applies to instruments that are not required, according to the POH, MEL or whatever, for the type of flight that's being attempted.)

[englishal]

Not a big deal for a VFR flight in VMC. Not very much instrumentation is required, no gyros for starters.

[SNS3Guppy]

Not very much instrumentation is required, no gyros for starters.

If it's installed, it's required. Two standards must be met for airworthiness; it must be safe, and it must be legal. In order to be legal, it must meet the type certification standards, or must be acceptably altered by regulation, STC, or other legal means. Simply telling the student that "we don't need it today" doesn't cut it.

[IO540]

If it's installed, it's requiredReference?

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

One could sure document those things but much of that stuff could have easily moved, and I would hope any investigator with more than half a brain will know that.

Some things are unlikely to move e.g. the heading bug, which is substantially geared down (unless the instrument is well smashed).

[ShyTorque]

Nutloose,

I think I can see what point you are trying to make as an aircraft engineer/ mechanic but that report really isn't a good example to support it.

It's a world apart from the situation put forward by the OP. The circumstances leading to that accident are very different to an early syllabus VFR instructional flight where only external visual references are used. Again, an AI is not necessary for such a VFR flight. Later ones, yes, as an instrument scan is introduced. If an RAF student had been prone to looking inside at the AI/DI during early lessons he would have failed the trip.

Later on in the syllabus PPL students are required to fly a series of lessons on instrument appreciation, albeit still flown in VMC as per the requirements of the ANO. Obviously, a fully functional vacuum system would be a priority for those flights and I would ensure any student of mine was fully aware of the difference.

The accident report shows that the pilot of that aircraft quite possibly flew into IMC over mountains in forecast icing conditions. Irrespective of aircraft instrument serviceability, it was foolhardy to have attempted that flight on that day, due to the terrain and prevailing met. conditions. Any sensible pilot would have realised the flight could not be safely made.

The report states that the pitot heat switch was found in the off position. If I read it correctly, there was a 4,000 foot difference between the elevation of the ground at which the accident occurred, compared to the reading on the altimeter as found in the wreckage. Pitot static icing is the only reason I can think of that would have given that very large altimeter error. This would probably also have given false IAS indications too. This is why we must avoid IMC in icing conditions at all costs in aircraft not equipped to deal with them. :)

[Mark1234]

If it's installed, it's required

Would love to find a definitive answer for this for the UK (don't care about FAA land) - in Aus it was (fairly) clear in the regs, here I can't find anything.. (surprise).

Why? In certain aircraft I'm in the habit of pulling the breakers on electric gyro stuff (and would kill the vac stuff if I could) pre-flight as an matter of sympathy - they don't cope well with aeros, and it only wears them out faster for zero benefit. Never really occurred to me I might be rendering the flight illegal :ugh:

To BackPackers point, I keep a few postit notes in my flight bag, perfect for covering things.

[Plasmech]

The only time we would have NEEDED the AI was if we accidentally flew into clouds. I am well aware that there are plenty of aircraft out there that do not have AI's and in fact Lucky Lindy crossed the Atlantic without one (although he did have a couple level bubbles) but the fact is that we had one. So let's say the flight continues. Do we placard an AI that *appears* to work but that we don't know for sure if it does or do we placard and have nothing to look at in a incidental cloud except our turn coordinator in this case?

When I say "placard" I mean to block from view completely.

I am aware that this stupid vacuum gauge conversation is going WAY beyond what it should on a simple early VFR lesson by a very low time student.

[SNS3Guppy]

Reference?

Given that the original poster is flying in Pennsylvania, USA, then 14 CFR 91.213 applies:

§ 91.213 Inoperative instruments and equipment.
(a) Except as provided in paragraph (d) of this section, no person may takeoff an aircraft with inoperative instruments or equipment installed unless the following conditions are met:
(1) An approved Minimum Equipment List exists for that aircraft.
(2) The aircraft has within it a letter of authorization, issued by the FAA Flight Standards district office having jurisdiction over the area in which the operator is located, authorizing operation of the aircraft under the Minimum Equipment List. The letter of authorization may be obtained by written request of the airworthiness certificate holder. The Minimum Equipment List and the letter of authorization constitute a supplemental type certificate for the aircraft.
(3) The approved Minimum Equipment List must -
(i) Be prepared in accordance with the limitations specified in paragraph (b) of this section; and
(ii) Provide for the operation of the aircraft with the instruments and equipment in an inoperable condition.
(4) The aircraft records available to the pilot must include an entry describing the inoperable instruments and equipment.
(5) The aircraft is operated under all applicable conditions and limitations contained in the Minimum Equipment List and the letter authorizing the use of the list.
(b) The following instruments and equipment may not be included in a Minimum Equipment List:
(1) Instruments and equipment that are either specifically or otherwise required by the airworthiness requirements under which the aircraft is type certificated and which are essential for safe operations under all operating conditions.
(2) Instruments and equipment required by an airworthiness directive to be in operable condition unless the airworthiness directive provides otherwise.
(3) Instruments and equipment required for specific operations by this part.
(c) A person authorized to use an approved Minimum Equipment List issued for a specific aircraft under subpart K of this part, part 121, 125, or 135 of this chapter must use that Minimum Equipment List to comply with the requirements in this section.
(d) Except for operations conducted in accordance with paragraph (a) or (c) of this section, a person may takeoff an aircraft in operations conducted under this part with inoperative instruments and equipment without an approved Minimum Equipment List provided -
(1) The flight operation is conducted in a -
(i) Rotorcraft, non-turbine-powered airplane, glider, lighter-than-air aircraft, powered parachute, or weight-shift-control aircraft, for which a master minimum equipment list has not been developed; or
(ii) Small rotorcraft, nonturbine-powered small airplane, glider, or lighter-than-air aircraft for which a Master Minimum Equipment List has been developed; and
(2) The inoperative instruments and equipment are not -
(i) Part of the VFR-day type certification instruments and equipment prescribed in the applicable airworthiness regulations under which the aircraft was type certificated;
(ii) Indicated as required on the aircraft's equipment list, or on the Kinds of Operations Equipment List for the kind of flight operation being conducted;
(iii) Required by § 91.205 or any other rule of this part for the specific kind of flight operation being conducted; or
(iv) Required to be operational by an airworthiness directive; and
(3) The inoperative instruments and equipment are -
(i) Removed from the aircraft, the cockpit control placarded, and the maintenance recorded in accordance with § 43.9 of this chapter; or
(ii) Deactivated and placarded "Inoperative." If deactivation of the inoperative instrument or equipment involves maintenance, it must be accomplished and recorded in accordance with part 43 of this chapter; and
(4) A determination is made by a pilot, who is certificated and appropriately rated under part 61 of this chapter, or by a person, who is certificated and appropriately rated to perform maintenance on the aircraft, that the inoperative instrument or equipment does not constitute a hazard to the aircraft.
An aircraft with inoperative instruments or equipment as provided in paragraph (d) of this section is considered to be in a properly altered condition acceptable to the Administrator.
(e) Notwithstanding any other provision of this section, an aircraft with inoperable instruments or equipment may be operated under a special flight permit issued in accordance with §§ 21.197 and 21.199 of this chapter.

The standard criteria for airworthiness must meet two tests: the aircraft must be airworthy, and the aircraft must meet type design criteria. If it's installed, it must work. If it doesn't work, then relief must be provided by a minimum equipment list, or the affected equipment must not be required by the regulations under which the flight is operated (day, VFR, for example) AND the affected equipment must be deactivated and placarded inoperative in a manner acceptable to the Administrator. Deactivation and placarding isn't merely a matter of putting a sticker on the item which states "inoperative." It also doesn't mean that a mechanical problem which presents a hazard may be taken aloft, as this isn't safe, and fails the two-prong test for airworthiness.

Furthermore, if the aircraft isn't airworthy and doesn't meet the conditions spelled out on the back of the airworthiness certificate, the airworthiness certificate is invalidated, and the person operating that aircraft is guilty of operating an unairworthy airplane, and one without a valid airworthiness certificate (two separate violations).

The only time we would have NEEDED the AI was if we accidentally flew into clouds.

Not really relevant.

Do we placard an AI that *appears* to work but that we don't know for sure if it does or do we placard and have nothing to look at in a incidental cloud except our turn coordinator in this case?

Whereas you have no way of knowing that the attitude indicator and turn and bank indicators are reliable without a functioning vacuum gauge, then these must be considered inoperative. Whether they "appear" to be working or not is irrelevant; you have equipment for which the only function indicator is indicating a bad vacuum value, and therefore you have several components indicating inoperative. The vacuum pump, the vacuum gauge, the turn and bank indicator and the attitude indicator. Your problem could be at any of these locations, and if the gyros are turning, this doesn't indicate that any item is turning properly or getting adequate suction. You could have broken pump vanes, loose hose connections, instrument case leaks, etc.

When I say "placard" I mean to block from view completely.

That's not what placarding means, but in the case of inoperative instruments, it's usually a good idea to cover them as well.

I am aware that this stupid vacuum gauge conversation is going WAY beyond what it should on a simple early VFR lesson by a very low time student.

It really hasn't gone beyond what should be covered. An instructor should be teaching you more than pulling back to go up and pushing forward to come down. You need to understand a number of factors surrounding your flying, from altitudes to use oxygen to regulations regarding seatbelt use. When an operational consideration comes up, such as inoperative equipment, you should be taught how to handle it. The instructor should never gloss over something or ignore it. These things are very relevant, especially in the early stages of your training. Weight and balance should already have been covered, as well as basic performance, and you should be very familiar with preflight procedures.

What do you do if you find something broken, leaking, or inoperative before the flight? How do you handle it? Can you go fly? This is pre-solo training, and it's very relevant to you. You want to solo an airplane, and you need to know what you're looking for, what it means, and the legalities of what you're going to do about it. If you find something before takeoff, how does that affect your flight, vs. something you found during the walk-around? You need to know this. This conversation has not gone beyond the scope of your original question, but is directly related to it, and is something you need to know.

Your instructor let you down, first and foremost. You were right to question his act. Now is a good time to understand why.

[Plasmech]

Guppy I didn't realize you were from the US as well. What state?

[SNS3Guppy]

I'm usually outside the US.

[NutLoose]

Mark1234 (http://www.pprune.org/members/143089-mark1234)

Join Date: May 2006
Location: Londonish
Posts: 681


Quote:
If it's installed, it's required
Would love to find a definitive answer for this for the UK (don't care about FAA land) - in Aus it was (fairly) clear in the regs, here I can't find anything.. (surprise).

Why? In certain aircraft I'm in the habit of pulling the breakers on electric gyro stuff (and would kill the vac stuff if I could) pre-flight as an matter of sympathy - they don't cope well with aeros, and it only wears them out faster for zero benefit. Never really occurred to me I might be rendering the flight illegal :ugh:

To BackPackers point, I keep a few postit notes in my flight bag, perfect for covering things.



Mark read this

http://www.caa.co.uk/docs/33/20101224_Draft7.pdf


ShyTorqueNutloose,

I think I can see what point you are trying to make as an aircraft engineer/ mechanic but that report really isn't a good example to support it.

It was a bad example, however what I was trying to answer was the query on how they could tell a analogue instrument could freeze to show what it was reading at the point of impact.

[IO540]

From the above CAA PDF:

Operational equipment defects are considered to be failure or malfunction of aircraft instruments, equipment or systems not required to comply with the Air Navigation Order Schedule 4 and 5, or EU OPS Subpart K and L as applicable. The pilot/flight crew may defer operational equipment defects.
The pilot/flight crew may also defer aircraft defects in accordance with a Minimum Equipment List (MEL) when approved to do so by the CAA.

(I had to unlock the PDF using this (http://www.unlock-pdf.com/) to enable copy/paste)

Obviously one can defer defects of equipment not required by the ANO, otherwise most of the flight training fleet, not to mention the rest of GA, would grind to a halt :)

[mary meagher]

I've had a few lessons at various USA flying schools, and rented a few dodgy aeroplanes ditto. Standard of maintenance used to vary horrendously.

If your flying school has a casual attitude to maintenance, go elsewhere.

If your instructor has a casual attitude to the condition of the aircraft and you are concerned, it is appropriate to politely decline to fly that day until it is sorted to your satisfaction; once again, go elsewhere.

If your instructor has a casual or gung-ho attitude to flying, you may both come to a sticky end. I know of a case where a show-off climb out was attempted by an instructor with a student who did not know enough to be alarmed. The student was badly burned. The instructor did not survive.

[Kengineer-130]

Guppy, EXCELLENT post detailing the reasons for a taxy back to the ramp :ok:....

999/1000 you will get away with the "day VFR, it will be ok" mentality, and on first reading the OP's comments, I had a good think about if I would have gone or not, and decided I would have (as a mere PPL, but experienced aircraft engineer) canned the flight, and investigated the fault. Had I had an instructor with me, I would have probably (incorrectly) have gone had the instructor been happy. Classic, classic example of cockpit gradient, and ignoring your better instincts due to the "superior" position of a CFI sat next to you, in wholm you place a great deal of faith.

Being an engineer, I have on occasion had the niggling doubt about accepting a seemingly minor fault, but the acid test has always been running through the possible cause of the fault, & concequence of further failure. Your point about the gears driving the other accesories is very valid, and another point made earlier in the thread, which the OP did not mention until later was that the pump had just been replaced, which begs the question was it even checked or connected properly? :eek:

This is a great bit of reading, and nicely illustrates the "holes in cheese" or "flight safty chain" accident causes theory. What COULD have become of a simple, seemingly innocuous minor fault? The chance to break the chain of events was there, and ignored, how easily it could have snowballed?

Thinking about it, this chain of events could have started even before the flight took place, as if the pump was replaced due to it SEEMINGLY failing, then (making a big assumption here) not being fitted/connected correctly or U/S on fit, which then failed to get tested, could infact be masking a much more serious failure such as gearbox breakdown etc:sad:

Food for thought...

[MarkR1981]

Nice to see some more sensible approches coming through:ok: flight safety has got to be number one priority.

[cats_five]

Thought probability would dictate that my first failure of any kind would take more than 5 flights to happen.

No, IMHO each flight is at a similar risk.

[IO540]

Not quite sure of that - in general.

The first flight after any service is the most risky. It is not unusual for things to go wrong straight out of an Annual. I've had that myself. That is one reason why I insist that all inspection panels are left open so I can inspect the plane myself. Not all companies like that and they are usually the ones whose employees are banned from flying the planes they work on "for insurance reasons" :yuk:

I also fly alone the first 1 or 2 flights, make sure they are VMC, and avoid water.

So, since any flight will be more distant from the last service than the previous flight, it follows that each flight you do will be less likely to suffer a service-related issue than the previous one :)

That logic would be wrong however if they merely left something loose, which comes undone only after N flights. However I think this is less common than "infant mortality" defects.

The bottom line however is that pilot error dominates in GA so the more you fly the safer you will be (per airborne hour). Unless you are a total cowboy who is just looking for a place to have an accident :)

[cats_five]

Not quite sure of that - in general.

The first flight after any service is the most risky.

Yes, agreed, was going to add that but wanted to keep it simple - my point is probability has no idea if's one's first (or nth) flight. And possibly the flights approaching a service are more risky as well...

[SNS3Guppy]

A senior captain once remarked to me that our job (speaking generically as pilots) is to find a way to make a flight happen, despite the roadblocks and situations which may arise. That's why we get paid, he said.

I disagreed then, and disagree now.

As private pilots, one doesn't get paid (except for certain circumstances in the UK, apparently). However, whether professional or private, one's duty as the pilot in command (we'll extend that to the student in this case, as the student's butt is tattooed to the same piece of flying real estate as the instructor) is to ensure the safe conduct of the flight. In practical terms, this means looking for as many possible reasons as one can that the flight should not go. Our job? Find reasons we shouldn't take off. If we can't find any compelling reasons, then we may be able to leave mother earth. Until then, look hard with a skeptical eye.

Some years ago the FAA did an exercise in which several hundred instructors participated, moi included. A light airplane, a Cessna 150, as I recall, was presented with various unairworthy items, and we were required to inspect the airplane and cite as many as we could find. The person who found the all the items, or the most, won a prize (I still have the snap-on screwdriver that was given as the prize).

Items included switched nav light lenses (color on the wrong side), and other obvious items, but also a number of not-so-obvious items. I came up with a full page of discrepancies, and later learned that only half of them were what the FAA had done to the airplane. It turned out that quite a few more items were found wrong with the airplane than the FAA thought. It also turned out that until they started messing with the airplane, it was thought to be airworthy. In fact, it wasn't.

Things which seem small may be the only warning you get of something that turns big. That little bit of dust collecting on the undersurface of the cowl or wing might be the only warning you'll get of an impending fuel or oil leak. Those little dusty streaks you sometimes see on the back of the propeller may be the only warning you get of an impending crankshaft seal failure, or propeller failure. That little nick you see in the prop, the one with the triangle shaped indentation ("stress riser) may be the only visual cue to an upcoming propeller failure or separation. That occasional vibration in flight may be the only clue you have in advance of a propeller failure or phenolic failure in a constant speed propl.

Aircraft talk to you. You may not speak the same language, but make out as much as you can, because often the airplane talks in very small, quiet language, and it may be the only warning the airplane gives before something goes wrong. You notice the ammeter bounce a few times, but don't think much of it; it may be your warning of an impending generator or regulator failure. Slight smell of smoke; it might be your last warning before the fire. Engine hesitates, coughes, slight vibration; you might not like what's coming next. Far better to stay ahead of it, whatever it is. Don't be like so many owners or operators who decide they'll wait until the next 100-hour inspection to "check it out."

As I stood in the troop door of a C-130 years ago, loading chemical, I studied Tim, a somewhat pear-shaped, whizened, experienced captain who had more time in that airplane than I had total time. He was gazing thoughtfully up at the underside of the wing, lost in some mental fog, looking very senile. I figured he was off in la-la land some place, and went about my business of loading the thick bentonite and sewer water concontion the Mexicans had come up with for us to fight fire. At length, Tim turned slowly to stare through me, a far-away look in his eyes, and said simply "shut it off."

I did. We stopped loading, already about 20,000 lbs of mud aboard, and I joined Tim. Soon we were both looking up at the dirty underside of the left wing, just outboard of the number 2 engine, and I still had no idea what we were seeing. The wing was dirty; we'd been in and out of smoke all day long, and all day every day for the past couple of weeks, fighting fires around Monterrey. Ask, dust, and dirt was everywhere. We didn't have the usual firehoses and equipment to clean the airplane, so we kept getting dirtier and dirtier.

Two small patches of ash held Tim's attention. Both in line with each other on the same wing station, one was several inches in diameter, the other an inch or two. What I was seeing didn't dawn on me until Tim pointed it out; the wing was cracked. The small cracks in the skin of the wing allowed fuel to seep out, and the very minute quantity of fuel had attracted ash, to form these two stains that held his attention. They looked like the rest of the dirty ash all over the airplane, except these two stains were in line with each other, one ahead of the other, on the same line running aft from the leading edge of the wing.

A crack anywhere merits investigation, but two cracks in the same area, aligned with one another merit special attention, because they may speak to a much larger crack. We chemically stripped the paint along that wing station, and performed a dye penetrant check. We discovered that indeed there were two cracks, not actually visible before the paint was removed. One was about an inch long, and several feet forward of that, another crack about an inch and a half long was found. Tim immediately grounded the airplane. We took it out of service, and after some long consultations with designated airworthiness representatives and engineers (aeronautical engineers, not just mechanics like myself), we secured a ferry permit full of restrictions, and flew the airplane empty back to the United States.

We stopped in Laredo, then flew to Greybull, Wyoming. We weren't permitted above 18,000', more than 180 knots, no more than 50% flap, no more than light to moderate chop, and so forth. As we burned off fuel and the wings became lighter enroute from Laredo, the wings bent upward more, a natural coning effect known as wing bending moment. The flight engineer began making trips to the aft troop door to look through the small round window behind the wing, and reported that every time we hit a "bump" he could see a burst of white mist, fuel, spraying from the wing along the station where the cracks were located. The last hour or so of the flight, it became a steady stream of fuel. We kept transferring fuel outboard to reduce the wing bending moment.

In Wyoming, I was part of the inspection team that did the non-destructive testing, ultrasonic mostly, on the wing, and it was the first time inside the C-130 wing for me. I didn't realize, until that point, that the C-130 wing is largely skin; it doesn't have much of a spar to speak of; its a shear-web that really does little more than form the fore and aft integral fuel cell walls. The wing has ribs for shape, and some reinforcement here and there, but largely it's held together by the skin; thick 7075 T-6 aluminum skin. Crack the skin, the wing comes off. We found that the crack extended the full circumference of the wing, though it wasn't visible yet. We inspected the right wing, and found the same thing. We removed the wings. One got repairs, the other got replaced. We were fortunate that neither wing separated in flight.

Several years later, both wings came off that airplane in flight, during an active wildfire near Walker, California. Tanker 130 took several friends of mind with it as the wings came off, it rolled inverted, and exploded from 200' at the end of a drop run. The failures didn't happen in the same place, but were existing cracks in the center box section of the wing, in the fuselage area, which came from a stress riser between driven rivets nearly 40 years previously. The crack existed in the middle of 5 layers of aluminum, hidden and minute for many years, and began to work and propagate in the severe turbulence we often encountered. Small things became big things, and while the warning signs were there, they spoke subtly at times.

Don't ignore little things. They become big. I've seen a few drops of oil behind a propeller governor stephead base become an engine and wing and exhuast covered in oil on the next flight, when the stephead base failed. It's interesting to see oil pressure drop, and lookout to see the engine and wing covered in flowing oil. I've had cockpit go completely dark out over the desert at night, and only then did I realize that the little bounce on the ammeter was the airplane trying to tell me something. An occasional slight vibration I felt in a brand new Air Tractor 802 seemed to be my imagination. In and out of a lot of mountain turbulence, I figured it was just me. I turned the airplane over to a friend (now deceased), and happened to call him a week or two later. He mentioned the airplane was down for service; he was preflighting and found excess movement in one of the five propeller blades. If he hadn't caught it, he could have had a very serious problem. The slight occasional vibration I felt was that same problem in it's infancy.

Some slight binding on the controls of a Seneca once didn't feel quite right. Some investigation into the problem revealed that the ELT had come loose from it's mounting bracket and had wrapped around the elevator cables, and was binding them. That could have been problematic. In a cherokee, I examined, the controls seemed to have resistance, and I found that wire bundles were binding under certain conditions. More disturbing, I found that the controls could be jammed under certain circumstances. That slight resistance was all the warning one might have had.

On another occasion, an intermittant nav light turned out to be a short in the wiring underneath the back seat in a different Seneca. It could have caused a fire. I found it was I was inspecting the wiring, when it burned my finger as I moved the wiring slightly. On another light twin, I found a short that disabled flaps and prevented their movement; the flaps went down but wouldn't come back up. A slight hesitation in the flaps was all the warning the owner had, but I found that moving the wiring and the flaps at the same time produced blue flashes inside the insulation, and the problem would have become progressively worse.

I was called into an inspection on a C-82, and found a squawk involving a fuel leak. It was signed off as "could not duplicate," one of my great "pet peeves." I hate CND write-ups, because mechanical errors do not fix themselves. In this particular case, I found the problem, though it took nearly three hours to duplicate, and when I did get it to start leaking, it poured out at three to five gallons a minute. The location of the leak, in the engine accessory section behind the R-2800 CB17 motor, would have been uncontrollable in flight; it would certainly have spread back to the left main gear and the wing and tail boom. I have no doubt it would have been fatal. A fuel leak was passed off as unrepeatable and unfindable; not listening to the airplane would undoubtably have killed somebody.

We can go on like this for volumes, and each story will point to the same thing; relatively minor appearances that most people (including myself) were inclined to dismiss, and which could have been or turned out to be catastrophic. Each time I have such an experience, or hear about one or read about one, I temper my judgment a little to become more conservative, to remind myself to look more closely, to be more willing to say "no."

One of a pilot's most important attributes, one of his single most important skill sets, is the ability to say "no."

In the formative first hours of a pilot's career, be it a long professional one, of a happy limited lifetime of private flying, the instructor cannot afford to set a bad example. The starving instructor who really needs every flight hour to pay for his next meal might feel inclined to take a student in gusty conditions because he knows that as an instructor, he can handle the situation. The student may be given the impression that such conditions are okay, perhaps even a false sense of security, and may be lead to enter such conditions as a private pilot on his or her own, later on. Such was the case with an individual I knew, who stacked up a Cessna 172 at a remote airstrip in gusty crosswinds. He was following the example he had been taught.

I have a background involving doing a lot of things with airplanes that aren't things that most should do. I was trained very early on to fly under powerlines, for example, as part of my agricultural background. Not something I will show a student, as a rule; not because it can't be done safely (it can), but because of the example it sets. A wise instructor once told me to never do anything I wouldn't want a student to do, because no matter how much I might try to separate my activities from the training environment, the student will see, and the student will observe, and the student will mimic.

An instructor with a student is perfectly capable of flying without gyros on a crisp spring VFR morning. It's really not the point. It's a teaching environment, a learning environment, and it's especially an important environment in which to do everything right.

On top of ethical issues, while a gyro can appear erect with only a little vacuum value, one that isn't rigid in space and spinning at the proper RPM puts excessive loads on the ruby needle bearings, which leads to instrument damage and wear. It's hard on the equipment. If a hose is loose, it's then an issue of intentionally operating the system and allowing contaminants into the instruments, bypassing the filter, and leading to the possibility of failure later on. The pitot static systems, and the pneumatic instrument systems should be considered sacrosanct and sterile. Don't risk contaminating them. It may not seem like a big thing, but something as simple as a bit of tape on a static port has brought down an airliner before. Treat the airplane you fly like our life depends upon it, because it really does.

I strongly encourage everyone to take their airplane seriously. It's a long way to fall, a lot of money to pay, and a hard lesson to learn for ignoring the obvious. Even when it speaks to you in quiet tones and words that aren't always easy to understand. Listen to your airplane. It speaks.

[BillieBob]

If it's installed, it's required
Would love to find a definitive answer for this for the UKYou won't find it because it doesn't exist. Article 41(4) of the ANO states "An aircraft must not commence a private flight, an aerial work flight or a public transport flight if any of the equipment which must by or under this Order be carried in the circumstances of the intended flight is not carried or is not in a fit condition for use...." However, under Schedule 4 "A means of indicating whether the power supply to the gyroscopic instrument is adequate." (i.e. a vacuum gauge) is not required for flight under VFR, even on a public transport flight.

Consequently, a defective vacuum gauge, being "equipment or systems not required to comply with the Air Navigation Order Schedule 4 and 5" falls under the EASA Part-M definition of an 'operational equipment defect' rectification of which, as IO540 points out, may be deferred by the flight crew without reference to an engineer.

This not an opinion as to whether launching with a defective vacuum gauge is a good thing, merely a statement of the current facts under UK law. Of course, this may all change when EASA-OPS comes into force.

[mary meagher]

Hi! I've sent a personal message to you, I liked very much what you said about the warnings of problems that seem small at the time, but can be symptoms of trouble ahead.