U/S Instruments - should an aircraft be flown with them?

[Grob Queen]

I was interested by a comment in another thread reference aircraft instruments being u/s, and yet the aircraft still airworthy.

Forgive my ignorance but methinks that if ANY instruments are u/s in an aircraft, then the whole aircraft is u/s and not flown?! In our club this is certainly the case. The only thing we will fly with (as I do frequently) is a DI which throughout a lengthy navex requires realigning with the compass. My QFI explained that this is because the instrument is just old, but it is a fault that we know about and can live with. I would be interested to hear what the experience is of those experienced ladies and gentlemen ppruners.

Thanks all
GQ

[Piper.Classique]

Flying in vmc to vfr? Oil pressure and temperature, rpm, asi, altimeter, magnetic compass should do the trick. Anything else your local airworthiness authorities require and job done. A turn and slip is on the french list, but the turn part of ours has an off switch and I wouldn't worry if it failed. I do like to have a cylinder head temp gauge but can live without it if not towing.

[Whopity]

Very shortly the EU Law will say something like this:NCO.IDE.A.105 Minimum equipment for flight
A flight shall not be commenced when any of the aeroplane instruments, items of equipment or functions required for the intended flight are inoperative or missing, unless:
(a) the aeroplane is operated in accordance with the MEL, if established; or
(b) the aeroplane is subject to a permit to fly issued in accordance with the applicable airworthiness requirements.

[Genghis the Engineer]

For a transport aeroplane there's a document called the MEL - Minimum Equipment List, which defined the stuff that has to be working.

For e.g. training aeroplanes, the document trail is a little vaguer, but ultimately a decision is made by the Captain, or if a student is flying it, the club, as to what is considered essential.

There are however numerous cases where it's perfectly reasonable and safe to fly an aeroplane, even in the training environment, with unserviceable instruments. You don't for VFR flying need many of the IFR instruments (AI, T&S...), for much flying the compass will serve without the DI being serviceable, very often the second altimeter is only a "nice to have".

Engine instruments are again subject to opinion to some extent. EGT isn't strictly required on most engines, whilst similarly unless you have a variable pitch prop, an MAP gauge is no more than a nice to have. On the other hand, I'd not fly many - if any - 4-stroke engines without a working oil pressure gauge, for example.

On the other hand, if instruments are fitted, I'd always much rather have them working than not! In a well run club, insisting on a high degree of serviceability is thoroughly sensible.

G

[POBJOY]

As Genghis states, unless the aircraft has a specific MEL (PT usually) then the situation rather rests with the operator (AND THEIR CLIENTS).
If the operator offers a machine that lacks some of what would be considered 'basic instuments' then i feel the client would do well to look elsewhere for a machine. If you are training how does one get used to scanning for information if no information is available. I would suggest that an economical attitude to servicability is not an ideal environment for training or aircraft hire;especially for low hours pilots.
Simple querstion; how do you justify not providing a 'fit for purpose machine' on a regular basis.

[peterh337]

I don't know of any piston GA plane which has an MEL.

What can be relevant is anything in the airworthiness limitations section of the POH; that stuff is mandatory.

But in general for VFR you need very little in the way of nav/com avionics. You are likely to need specified engine instruments though: oil temp, oil pressure, RPM, etc.

how do you justify not providing a 'fit for purpose machine' on a regular basis. Not a question you want to ask too casually having walked into the average flying school :)

The answer has to be that this is a competitive business in which almost nobody is making loads of money, so the name of the game is how far the fleet can be run into the ground without losing too much business. It's a bit like running an ISP :)

I walked out of one school, 20hrs into my PPL, due to crap (dangerous) maintenance.

methinks that if ANY instruments are u/s in an aircraft, then the whole aircraft is u/s and not flown?! That is certainly not the case legally, in private GA.

In our club this is certainly the case. If I may say so, that is perhaps because you are operating very simple aircraft.

I, as a private owner with adequate funding, can and do operate a TB20 on that basis, but I have never heard of a commercial owner who does that, on aircraft with anything vaguely resembling a decent VFR/IFR capability. You might have two radios, of which each costs $4000 to replace, or perhaps $2000 on an exchange/overhaul basis. Most owners are not going to do that immediately. It is made a lot easier by having various spare avionics on the shelf, but again most owners don't have that. I bought a pile of stuff from some Americans who upgraded to a Garmin 500 or Aspen :)

[frontlefthamster]

I don't know of any piston GA plane which has an MEL.

I spent all day yesterday flying one... Different levels of experience, I guess, you and I.

Go on, Peter, you'll doubtless be able to tell me why some GA piston aircraft do operate under MELs, if you put your mind to it.

The crucial difference between the hypothetical private pilot finger-in-the-air and the MEL is that the MEL should consider subsequent failures and meets the authority's expectations.

Would you care to explain the paper trail which supports operation of defective GA aircraft without MELs, please?

[peterh337]

Which one was it?

If you really wanted to teach somebody something, Mr Hamster, you would have posted the type, and the details. Instead you just want to wave your willy, by posting half the info. Next time you will be saying you are the head of training at an FTO and a CAA examiner.

I picked up one error in your post though: "authority" is spelt with an uppercase "A".

[Genghis the Engineer]

I don't know of any piston GA plane which has an MEL.

The Islander certainly does, I remember writing one version of it when I was working for B-N.


The actual process is that the manufacturer generates an MMEL, then the operator creates their own MEL as part of their AOC procedures.

However, without an AOC, there's no legal requirement for an MEL, and it can be far more trouble than it's worth if there's no legal requirement for it.


A badly written MEL can be an utter menace - I had much mucking about recently with an aeroplane where some pillock a few years back managed to write the satcom system into the MEL, so we had to go through all sorts of stupid paperwork hoops to legally fly when one of the satcom LRUs fell over.

G

[blagger]

I think the CAA adopt the FAA generic single engine MMEL for most types - for example the A1 Single Engine one for PA28.

PA 28 FAA MMEL: Single Engine Aeroplanes Revision 1 | Publications | CAA (http://www.caa.co.uk/application.aspx?catid=33&pagetype=65&appid=11&mode=detail&id=922)

[riverrock83]

A flight shall not be commenced when any of the aeroplane instruments, items of equipment or functions required for the intended flight are inoperative or missing:

So is there somewhere a list of items which are required for a particular non-air transport flight? Is it up to the pilot what is required for the intended flight?

I was regularly flying in a permit aircraft with U/S nav equipment. Eventually the operator removed all of the nav equipment from the plane (must have been properly unserviceable!). I'm told that a new W&B had to be done after all the extra aerials and wiring were removed and there is now a slightly higher cruise and better fuel economy...

[frontlefthamster]

Peter, in a moment of unexpected and ill-judged childishness, you wrote:

I picked up one error in your post though: "authority" is spelt with an uppercase "A".

I was referring to the competent authority, not a particular Authority.

This might help:

List of Master Minimum Equipment Lists | Publications | CAA (http://www.caa.co.uk/application.aspx?catid=33&pagetype=65&appid=11&mode=list&type=sercat&id=16)

The type I was flying is on the list, though it was not a G-registered aircraft.

I'm neither Head of Training nor a CAA (or DGAC) examiner... Much higher up the food chain than both of those! :)

[Genghis the Engineer]

I was regularly flying in a permit aircraft with U/S nav equipment.

The TADS or HADS for BMAA administered microlights have a de-facto MEL, which varies between types.

LAA paperwork is a bit more random.


There are requirements in the ANO of-course for minimum instrument fits for certain types of airspace.

G

[dont overfil]

Hi GQ,
Something I'm surprised nobody has picked up on is your comment about the DG needing realignment occasionally.
This is caused by precession due to the rotation of the earth. Admittedly a worn instrument makes it worse.
You will learn about it when you get to the technicals then you can inform your engineer.:ok:
D.O.

[frontlefthamster]

You're most kind... ;)

(I've never been to a bad party at an embassy, but have never never been the host either...).

Still waiting for Peter to return and answer my question...

[Cobalt]

Since the OP asks about a club environment, let's just go back to the new EU Ops regs that whopity quoted, since they apply to a renter.

It says that you need to fly in accordance with an MEL if you want to operate with less than the REQUIRED instruments.



So - which ones are required ones?

Whatever is required in the POH, of course (Typically section 2 - Limitations, but might be elsewhere or in several places)
For VFR, a magnetic compass, a clock, an altimeter, and an airspeed indicator (NCO.IDE.A.120)
For IFR, in addition turn-and-slip, attitude, vertical speed, DI, outside temperature (NCO.IDE.A.125)
For VFR night as under IFR, but you don't need the thermometer (NCO.IDE.A.120)
At night, various lights (NCO.IDE.A.115)
A first aid kit (NCO.IDE.A.145) and a fire extingisher (NCO.IDE.A.160)
Radios, nav receivers etc. if they are required by the airspace you want to fly in or to maintain the route (various)
So, in your case, very little indeed. But this is for private ops, ie, you as a renter. If you are receiving training, the operations manual of the training organisation is relevant, and it might well have a MEL or other rules you should stick to.
As an aside - in the new EU OPS world, which part does actually apply to training organisations during training?

[Cobalt]

Would you care to explain the paper trail which supports operation of defective GA aircraft without MELs, please?

See above - for non-comercial non-complex ops there is no requirement for an MEL, and you can operate in accordance with the legal minimum requirements and the requirements in the POH (an obey both). Indeed since MELs need approval by "the authority", the "authority" would be hard pressed if they jad to agree MELs with every single spamcan owner...

[frontlefthamster]

I'll play along...

To begin:

Where is your reference that only AFM Section 2 contains the restrictions?

[dublinpilot]

Still waiting for Peter to return and answer my question...

I'm not surprised. You're posts on this thread are reeking of smugness, and I certainly wouldn't take your bait if I was h im.

Why don't you just help us and generously pass on your knowledge in a kind open and honest mannor as most knowledegable posters here do? I'm sure we all enjoy learning something new when the knowledge is imparted in a friendly way.

If you are trying to show us how much more intelligent you are than the rest of us, then I'm afraid that I'm getting a very different impression from your posts; one that I'm sure you wouldn't like to be convayed.

[frontlefthamster]

No.

Lots of people are confidently proclaiming that this, that, or the other, is hard fact. Very little of it is. The best answer is to challenge falsehoods.

Too much time is wasted by people reading and posting in forums such as this rather than finding out the right answers, or indeed, valid questions. I get fed up of this because it's damaging the pilot community in general.

I'm happy to pay along with funny games such as cjboy's, but am very well aware of my own frailties. That awareness has served me well for many years in many cockpits and flight decks, not to mention board rooms, courts, and other pressurised situations.

Peterh, in particular, is a purveyor of mis-information hidden behind an aura of experience and expertise, in my opinion.

If you want knowledge, go to the original sources; don't waste your effort in an internet chat-room.

[Maoraigh1]

I clicked through on the links provided, from CAA to FAA. I clicked through on Cessna. No 100 series aircraft appeared to be there. (150/152/172 etc)

[BillieBob]

As an aside - in the new EU OPS world, which part does actually apply to training organisations during training?Following hamster's advice, we go to the original source - in this case, initially, the EASA CRD on the OPS Regulation (CRD OPS II) where, in the section titled 'Addendum to the Cover Regulation on Air operations and Annex I - Definitions' on page 10 of 155, we find the statement:

"As regards the applicable operational requirements for approved training organisations, it is proposed that flying training by ATOs is conducted in accordance with either Part-NCC or Part-NCO, depending on whether the aircraft is complex motor-powered or not and regardless of whether it is a commercial or non-commercial activity (Article 1(2) point 9)."

Assuming, therefore, that the training is taking place on a single-pilot, piston engined aircraft with less than 20 seats and weighing less than 5700kg, it is Part-NCO that applies to training organisations.

In relation to minimum equipment lists, Part-NCO, as it was submitted to the EC, states:

NCO.GEN.155 Minimum equipment list
An MEL may be established as specified under 8.a.3. of Annex IV to Regulation (EC) No 216/2008. In that case, the MEL and any amendment thereto shall be approved by the competent authority.

It does not, therefore, mandate a minimum equipment list but allows it as an option. Hamster will also be pleased to note that 'authority' is not capitalised.

[Gertrude the Wombat]

Simple querstion; how do you justify not providing a 'fit for purpose machine' on a regular basis.
Well, there's fitness for which purpose, and how regular is regular.

An aircraft with instruments which are U/S until it goes into the shop in two hours time and which as a result cannot be flown in cloud might well still be fit for purpose VFR, and from the punter's point of view this might well be preferable to having the aircraft taken out of service earlier and having the resulting higher hourly rental charge.

At a more basic level if I'm flying circuits or doing a well-known local tour I don't give a toss about nav instruments, whereas if I'm going somewhere new I'll want at least some of the avionics to be working!

Is it up to the pilot what is required for the intended flight?

It is if it's me and I'm renting! - if enough things are broke I won't accept the aircraft, the club can either offer me another one or I'll go home.

So far this has happened to me exactly 0 times although it's been close, in terms of broken avionics, once or twice. Sounds to me like a club with a reasonable understanding of the requirements and tolerance of its punters :)

[mad_jock]

Welll personally I think there is something quite special going up in cub with only the minimum fitted.

Wet compass, no artificial horizon a few engine instruments and a window to look out of.

Its your cash if you want to hire an aircraft with everything working don't accept it if there are things broke. And when you phone up to book ask if it has been fixed and if they say no , just say thanks but no thanks in that case. Don't get stroppy and start quoting MMEL's and all that stuff just say NO don't want it.

Enough folk do that and they will get it fixed.

I can completely understand why a punter would get up set if an aircraft is being punted as IFR kitted out when in realitity its not due to snags. You pay a premium for it so it should work even if you are only wanting a VFR machine.

The only way your going to get owners to fix stuff is by refusing to hire it. Just make sure they know that they have lost a rental by running it broke. But if there enough people willing to hire it don't expect them to fix it.

[peterh337]

That's fair enough but quite a lot of people have to go to a lot of hassle to get time off to fly on a given day, and they may have a long drive to the airport, so they are less than happy to find the plane is knackered.

It's one of the great advantages of ownership... you can maintain to your standards.

Peterh, in particular, is a purveyor of mis-information hidden behind an aura of experience and expertise, in my opinion.

Always happy to be corrected by a self proclaimed expert who won't reveal what he actually does :ok:

Was I married to you once?

[Rod1]

On an LAA permit the min for flight is asi, altimeter, magnetic compass, fuel level indicator plus engine instruments as appropriate (can be nothing). On top of that, individual aircraft may have specific requirements – some have MEL’s in the POH - some are LAA.

Rod1

[Genghis the Engineer]

On an LAA permit the min for flight is asi, altimeter, magnetic compass, fuel level indicator plus engine instruments as appropriate (can be nothing). On top of that, individual aircraft may have specific requirements – some have MEL’s in the POH - some are LAA.

Rod1

Just picking an aeroplane at Random, the BMAA TADS (http://www.bmaa.org/files/bm68_6_ikarus_c42.pdf) all contain a minimum instrument list - item 8 on page 6, although the page number may vary.

G

[rich_g85]

I flew a Robin a few weeks ago with no suction (so very sluggish AI and no DI). We were only going for a VFR bimble to the Isle of Wight and back to Bournemouth - if I hadn't accepted the aircraft my father would have had a wasted trip down from Leeds (no other aircraft available). However I was mindful not to get blind 'press-on-itis' but to carefully consider the 'risks'. It was a lovely day and I know the area well, just look out the window and use the compass if necessary. I guess it was my first real 'command' decision, but I wouldn't have gone if there was any chance of inadvertent entry into IMC as I have never done partial panel.

[fwjc]

I don't think the aeroplane knows how many instruments are on board apart from a cg perspective. I'm pretty sure the wings will still fly no matter whether the DI is 20 degrees out.

Bear in mind that there are plenty of aircraft that don't have gyro instruments. That kills the DI, ASI and Turn Coordinator. For VFR flight in simple types, an ASI, Altimeter, RPM, Oil Pressure, Fuel level indicator, Slip and Compass are plenty for me.

If your flight requires more instrumentation ie radio Nav, of course you need more kit. If you're flying complex type then more engine instruments such as MAP are relevant.

It is true, though, that if you are used to seeing lots of kit in front of you, it can be disconcerting to learn that it's okay without. I had that experience a long time ago learning to use a DI for Nav, then moving to an aircraft with only a wobbly wet compass. You soon find that it's okay!

[BackPacker]

I flew a Robin a few weeks ago with no suction (so very sluggish AI and no DI).

I have flown aircraft with U/S instruments as well. No problem for a Day VFR flight, as long as it's not one of the essential/required instruments.

However, I always tape a piece of card or something over it (and even scribble U/S on it for good measure) so I don't get confused.

[Cobalt]

Gengis refers to the type certification, an interesting source! For the use of the pilots, this should be reflected in the POH, anf for the Icarus (http://swiftinstruction.com/downloads/files/IKARUS%20POH.pdf) it is on page 15 / section 5. No idea if this a typical microlight POH structure. What happens if it is in the type certification data but not in the POH I have no idea - I don't believe the pilot is expected to see/know the TCDS/TADS data.

frontlefthamster, I didn't mean to say that it always is in section 2, but it has to be in the POH (ok, AFM) for aircraft certified under FAR 23, and this is where it typically ends up. Just in case you want the reference that it has to be in the POH:

"The Aeroplane Flight Manual must contain operating limitations determined under this part 23, including the following:"
....
(h) ....a list of installed equipment that affects any operating limitation and identification as to the equipment 's required operation for which approval has been given"

I corrected my post above to say typically.


The heart of what I wrote is that, for private operations of non-complex aircraft, the source for minumum equipment is the POH (whichever section) and the law, of which I quoted parts (there is more, and it might not be all in one place, either), and it is very little indeed. Broken stuff might have to be labeled INOP (no idea where that rule is).

mad_jock has the sensible answer - if what you have installed is broken, do you really want to fly with the aircraft? Persistently broken instruments can indicate shoddy maintenance. A few days ago, I took of in an Arrow with broken autopilot, and electric trim disabled due to a sticky trim switch (= risk of runaway). None of which are mandatory.

During the flight, the HSI failed, and the G/S indicator did not work. Both of which were more essential. Half of the purpose of the flight (ILS practice) was wasted.

[BackPacker]

What happens if it is in the type certification data but not in the POH I have no idea

I'm not the expert on this, but my gut feeling is that this situation is not supposed to exist.

As part of the certification process I think the certifying authority is required to take a look at the POH, specifically the "limitations" chapter, to verify that it complies with the regulations. And the minimum equipment list (whatever it is called) is part of that "limitations" chapter.

Of course for older/vintage aircraft, and non-certified aircraft this might not apply.

[peterh337]

Are there not two separate issues here?

The POH (for any modern-ish aircraft) should have a list of equipment which is required under the TC. For light piston GA, day VFR, this tends to be mostly basic stuff like the ASI and some engine instruments. For night VFR, it will be more stuff... For IFR, more again.

The "MEL" issue concerns how much of the stuff actually installed can be duff and you can still depart. This is obviously relevant to commercial (AOC) ops, where the intention is to prevent somebody gaining a competitive advantage by operating dangerous wreckage. It's the same with JAR/EASA OPS and weather minima; an operator who gets in or out under the minima is going to be getting a competitive advantage (so long as they don't kill too many passengers).

On any aircraft operated under an AOC, there is likely to be an MEL of some sort, referenced to the CAA-approved company ops manual. But AOC ops are not exactly "private flying".

[Rod1]

For those with little experience of Rotax 912 aircraft the following is a typical MEL for an LAA machine;

10.2. Minimum Equipment List

Flight instruments
Airspeed indicator
Altimeter
Magnetic compass
Ball bank indicator

Engine instruments
Tachometer
Oil temperature
Oil Pressure
Cylinder Head Temperature
Fuel Level indicator

Oil Level indicator (dip stick)

Rod1

[Grob Queen]

Hi, thanks for all your replies (and I finally worked out what MEL stood for ;) ) Tch, these student eh?!

Our use of the DI. I take the point that the ac still flies if the DI is slightly out or broken (!) but I think that my instructor is making me aware of the slight variation to make me check the compass and therefore realign the DI to a) make me fly accurately and b) help me learn my headings :hmm: I couldn't imagine flying without it!

D.O many thanks for your comment ref rotation of the earth, I understand now, so am I correct in thinking this is to do with magnetic variation, isogonals etc? As you can see, I have not started tech yet!

Peter - Simple aircraft? What constitutes a "simple" aircraft? Is it our Grob 115s? Does our Firefly constitute a more complex aircraft? We certainly have most instruments which are mentioned here also with the DME, VOR, RPM, VSI but no manifold pressure. We also have radios, Transponder, clock and timer, the usual Ts and ps and something which I have only just been introduced to - the very handy Carb ice indicator!

With only three aircraft in the club, yes we do need to maintain them!!! ;)

I ahve never seen an MEL for the Grob (or Firefly) I assume from the other posts here that not all aircraft have them.

One post mentioned an ops manual of the training organisation with relevant info. Many thanks for this steer, we have the Flying Order Book which may ahev something in and I can also pump our QFI for information tomorrow when I go flying with him :)

GQ

[frontlefthamster]

We seem to be moving in a more worthwhile direction.

However,

the intention is to prevent somebody gaining a competitive advantage by operating dangerous wreckage

does not reflect reality (is that a kinder way of putting it?).

I suspect the the regulators would, if questioned, say that the intention is to ensure that a suitable minimum standard is assured and continues to be assured for the fare-paying passengers. As it happens, operating aircraft which are not maintained properly costs much, much, more than the alternative. This has been proven time and time again. Some companies prolong their death-throes by running up defects, but never for more than a year or so at most, and those that do, always go bust.

I'm not going to discuss what I do, here. The fact is I enjoy my work, and am blessed to have an enormously varied and challenging range of things to occupy me both in a lovely variety of flying machines and elsewhere. I look at the oppportunities that aviation has given me, and I am profoundly thankful for them and the fact that they continue. I genuinely believe that the state of the industry means that I am one of a breed of our time; our antecedants will not be so lucky.

'The price of everything and the value of nothing' is the poorest guiding principle in aviation.

As for

you can maintain to your standards

Yes, you can, provided that

your standards

are equal to or higher than those of your regulator.

With regard to the

CAA-approved company ops manual

it's worth pointing out that the UK CAA does not approve operations manuals (in fact, it approves a couple of small sections in them, but not the whole thing). The rest of the manual is finalised when the CAA ceases to raise objections. Some other regulators work differently.

[GeeWhizz]

An understandable description of DI workings/errors pboyall :D. I can't remember the last time I flew with a DI that was stable for more than 5 mins let alone 15! Nevertheless its all part of the fun of flying; sometimes it's easier to ignore the DI and fly solely by compass for heading reference and challenge oneself to timed turns, 'UNOS' and such like.

I'll add only that the 115s at GQs club are SSEAs (toned down version of the EFT kites that have CS props). Their Firefly, although fixed gear, has a wobbly prop too, which I think classifies it as a complex type(?).

As far as U/S instrumentation goes, I don't mind Com2 and Nav2 being inop (frequently they are as it happens), and wouldn't mind other dials and 'lectric things/gizmo's/gadgets not to work; it's largely dependent the type of the proposed flight. A serviceable transponder is always a good idea though. Guess its good maintenance or just good luck that I've yet to fly with nowt but the natural horizon.

GW

[mad_jock]

There is no requirment what so ever that the DI is working for doing PPL lessons.

All thats required is that the wet compass is showing something that sort of aligns with the runway of departure.

[peterh337]

There is no requirment what so ever that the DI is working for doing PPL lessons.

I don't doubt that but would suggest that charging the current rates for flying such a heap is totally ripping off the customer, who is most unlikely to fly in such a piece of junk for real afterwards.

I think a perfect DI will indeed drift 15 deg/hr (doesn't it depend on where on the earth's surface you are?) but in my PPL training and subsequent self fly hire, all done with non-slaved DIs, I never saw one which was better than about 10 degrees every 10 minutes. That means constant resetting from the compass is needed, which is OK in still air :)

[mad_jock]

Any body that accepts anything even slightly pointed in a direction while flying VFR in class G is making a rod for there own back,.

ATC will not give you a service unless it suit's them for thier own reasons.

Tell them to knob off if they upgrade the service to move you out the way.

Personally i spot the traffic then aim at it. Especially if it a mill controller trying to matain radar seperation 3 miles outside the MATZ.

[frontlefthamster]

Let's consider things from the fundamentals:

A manufacturer builds an aircraft and provides a manual (let's call it the AFM) with it. The AFM makes no mention of operating with defects (this is usual). The regulator knows nothing of the aircraft's specifics and therefore also makes no provision for the aircraft to fly in a defective state.

The aircraft develops a defect.

Without an aleviation of some kind, it might be said that operating the aircraft with any defect at all invalidates the CofA (which is itself dependent upon operations being in accordance with the AFM). This is the UK regulator's traditional position (Cabair had huge arguments with the CAA about this many years ago when they wanted to, and were eventually allowed to, operate SEP and MEP aircraft off an AOC but with a quasi-MEL - another famous Belgrano climb-down).

That (notwithstanding the MEL considerations, which should only affect aircraft operated on AOCs in the UK) is how things stand.

Now, to the praticalities: An owner has an aircraft which develops a defect. Strictly speaking, this renders it unairworthy as described above. However, the owner flies it and nothing bad happens. A happy ending. If something bad did happen he might try to cover it up and might be found out. Not such a happy ending. The burden of proof, though, may be very difficult to shoulder. It is, in my view, most unlikely that, for example, negative consequences would arise in course of an insurance claim (insurers seem to lack both appetite and competence to defend claims in questionable circumstances, though less so now than some years ago).

So, my own advice would be:

Without an MEL everything on the aircraft must be serviceable before strictly legitimate flight.

Any defect renders an aircraft without an MEL 'unairworthy' but the practical consequences are few unless you have an accident which is blatantly connected to the defect and the insurer and loss adjuster have the bit between their teeth.

Hence my questions about Section 2 etc.

Please treat the above with a degree of caution; it's some years since I operated a G-reg airframe off AOC, though to the best of my knowledge, the words above are true.

(That said, my mind returns to a vacuum pump on a PARO which crashed after departing Inverness; I can't remember the details. Booze also springs to mind but I seem to remember a vac system defect - grateful for a reminder..?).

[mad_jock]

Without an MEL everything on the aircraft must be serviceable before strictly legitimate flight.

utter bollocks.

Flying looking out the window realistacly needs nothing. No compass no engine instruments absouletly nothing apart from a window to look out of. You need instrumets to comply with ATC but thats it.

to comply and be safe with other traffic needs one or two instruments.

Your really really trying to make out that VFR flying is something special when it really isn't.

[frontlefthamster]

utter bollocks

How erudite.

The OP asked about 'airworthiness' in respect of defects. That's what my answer dealt with, in formal terms which have not been contradicted.

As attractive as your thoughts may be to the practical aviator who embraces risk, they're wrong.

[GeeWhizz]

Mefinks PPRuNe needs a 'Like' button! MJ I'm with all the way. And 3 miles is a heck of a long way at 100kts if you can see where you are going;)

Edit: Ooooh, I posted this before posts #46 & #47

[waldopepper42]

Height, airspeed, direction. Everything else is optional.

[peterh337]

Without an MEL everything on the aircraft must be serviceable before strictly legitimate flight.

That's your opinion, Mr Hamster.

It's not the legal position for private flight in a certified aircraft, whose required equipment etc is defined in the POH.

It may be that if everything installed is only what is in the POH for "day VFR" then all of that must work for any flight. But most planes have a lot more stuff in them than is required for Day VFR, either in the POH or by the applicable airspace regulations. The "extras" don't need to work.

The Cabair example is a redherring because they are an FTO and are bound up in all sorts of ways, even if not doing charters which need an AOC anyway.

[mad_jock]

How erudite.

Are you meaning that as an adj? if so I accept your statement that I am learn'ed and showing extensive scholorship.

Or if your being a prat using a big word that you don't know what it means knob off.

[mad_jock]

go and get a video silverire.

I suspect your going to need a beep machine.

to me it only warrents a two word reply :mad: off knob end

[frontlefthamster]

ATC will not give you a service unless it suit's them for thier own reasons.

...now that is:

utter bollocks

Personally I spot the traffic then aim at it.

Oddly, that's also a technique for everyone from radar controllers to ship-drivers. If you're both moving (and not straight towards each other), and one aims at the other, you won't hit. Neither will you reliably achieve MSD, but in those circumstances, never mind.

Peter,

That's your opinion, Mr Hamster

Yes, it is. Thank you. Based on decades of experience and training.

It's not the legal position for private flight in a certified aircraft, whose required equipment etc is defined in the POH.


Where in the POH does it say which equipment may be unserviceable for flight?

The Cabair example is a redherring because they are an FTO and are bound up in all sorts of ways

Well, in fact, they've gone bust, so they were..., but more importantly, vague statements like 'bound up in all sorts of ways' carry no weight in aviation, and only end up an embarrassment.

[frontlefthamster]

I'm not talking about the FARs thank you. Neither was anyone else.

I hope you all understood my words 'strictly legitimate'. I think some of you are having real trouble there...

MJ, you are truly providing the highest quality entertainment. Thank you.

Rest asured I know exactly what each word I employ means...

...and that would include 'sarcasm'. Perhaps you can find that as well (it's under 's').

:p

[mad_jock]

I can if it suits me aim and utterly conflict with radar seperation without comprimising safety any radar seperation while VFR. I did it for 2 years with nimrod traffic in the radar circuit at Kinloss.

I was told getting onto 20-30 times by radar that I was getting MOR'd. I will let you guess how many times I was contacted by the CAA about the MOR's filed against me in class G airspace by Lossie radar.

Was that between ****e and Syphilis ?

[frontlefthamster]

Hook, line, sinker, subscription to the Angling Times.

[frontlefthamster]

...and that would include 'sarcasm'. Perhaps you can find that as well (it's under 's').


Was that between ****e and Syphilis ?

Pure gold!

Thank you so much. Haven't laughed so loud in ages. Good night!

[GeeWhizz]

Frontlefthamster

ATC will provide a service if it suits them. Any tinpot GA putt-putt plane flying through the climb out lane, the approach lane, or the overhead deserves attention, if for nothing more than to divert them around station based traffic. But realistically its so that reduced separation minima can be applied to the necessary degree. Any GA tinpot putt-putt plane that doesn't come within the above parameters is in essence a pest, and will receive an appropriate amount of attention in accordance with its type of service only. Sad but true.

Aiming at traffic is a fantastic way to 'avoid' confliction under certain conditions. These being dependent on speed, agility, type of transit, and type of service of the platinum pilot/plane combo. If any are lesser than the eejit being avoided a climb or descent is the best way to deal with the situation, unless of course you are in radio contact with said eejit.

If Mr Tinpot is VFR and Mr platinum isn't tough ****!

[Cobalt]

Frontlefthamster, I'd like that pointed out in writing in a piece of regulation and law, please, because the law only specifies that minimum equipment as required by the law has to be carried and servicable. I might have overlooked the paragraph actually prescribing that ALL equipment has to be serviceable for private ops, could you point it out?

On the other hand, EU OPS for non-commercial operations says
A flight shall not be commenced when any of the aeroplane instruments, items of equipment or functions required for the intended flight are inoperative or missing

(my bold). It says required. Not installed, required. If they meant installed, they surely would have said so?

You also asked where in the POH it says which equipment may be unservicable. It is the other way round - it says which equipment MUST be servicable. And there are plenty of examples - the two Piper POHs I have to hand say that required equipment is as required by the regulations, and the SR22 and Beech Baron POH I have in front of me contain MEL-style lists, for example in the Cirrus you must have 2 alternators and 2 batteries for IFR, but only one for VFR - which is an addition to equipment required by law due to the type certification as an all-electric airplane.

Of course if you want to fly with [U]less you need an MEL.

I only believe your suggestion, that you could not fly an aircraft if the cigarette lighter, cabin fan, or the electric trim, or even the autopilot are defective when you can quote regs - experience and training don't count.

[ProfChrisReed]

I do hate it when amateur lawyers witter on about legal requirements, particularly if their wittering is

Based on decades of experience and training.Far better based on the law, in my professional opinion (profession being law professor and part-time practitioner).

The law in question is the Air Navigation Order 2009 (as amended) paragraph 16(7) which reads:

An aircraft registered in the United Kingdom with an EASA certificate of airworthiness must not fly otherwise than in accordance with any conditions or limitations contained in its flight manual unless otherwise permitted by the CAA.So a defect in any piece of equipment whose proper functioning is not mentioned as a condition or limitation in the flight manual is not unairworthy, as a matter of law.

This leads to interesting consequences - for example, an aircraft with a broken elevator is still, as a matter of law, airworthy.

Once we move beyond the legal definition, we come to the more normal use of airworthy - is it sensible to fly it? With a broken elevator, no, and there are more general legal requirements (not endangering others, in particular) which would be applicable. But these are all matters of judgment, ultimately by a judge.

So, if something not falling within paragraph 16(7) is defective, you the pilot must form a judgment as to whether you consider you should fly the aircraft. Part of your deliberations might include the judgment a judge would come to if you plummet, in the traditional manner, into a school full of visiting puppies and kittens.

Anyone who says that a piece of unserviceable kit (outside paragraph 16(7)) automatically makes the aircraft unairworthy in the legal sense is simply acting the fool. As an example, my glider has flight controls which need to be connected, by me, once I have rigged it. These connections have safety pins (hurrah!). And the pins are attached by pieces of string, to stop me dropping them into the bottom of the fuselage. If the string breaks, my glider is nonetheless airworthy. Without the safety pin it is still airworthy in the legal sense, because the handbook does not require the pins to be fitted (just fittable), though I would decline to fly it in that condition because it wouldn't be airworthy in the non-legal sense.

[Edit: and I see that while I was writing this Cobalt said much the same, though less pompously]

[peterh337]

Based on decades of experience and training.Now we know who may have given the CAAFU people such a bad name :) I say "may" because I very much doubt Mr Hamster was ever a CAA FE.

I wonder if Mr Hamster is "DFC"? The writing style is similar.

You do get some right cases on here :)

So a defect in any piece of equipment whose proper functioning is not mentioned as a condition or limitation in the flight manual is not unairworthy, as a matter of law.I think that is more or less what I wrote, too, though less clearly.

This topic also touches on maintenance. In the USA, FAR Part 91, the same principle applies. Stuff in the Airworthiness Limitations section of the MM is mandatory. Everything else isn't (notwithstanding it being good practice, etc) unless called up in some equivalent reg elsewhere e.g. an ICA in an STC.

[Cobalt]

Thanks, ProfChrisReed, although I say it with less authority... I guess there is a trade-off between authority and style somewhere ;-)

[Pilot DAR]

Hmmm.... To jump in to the fray, or to not jump in.... what to do what to do? Okay, I'll play.....

I like the first few posts. I admit to not reading a few in the middle.

Add to the collective thinking that "airworthy" for a certified aircraft is often defined as something like: "Conforming to it's type design, and in safe condition.". I'm sure it says somewhere else in regulations that a pilot shall not undertake a flight in an aircraft which is not "airworthy", unless special authority (flight permit) is obtained.

The type design for an aircraft will generally state (via the type certificate data sheet, and to a lesser degree, the flight manual and/or parts catalog/maintenance manual) what constitutes the "type design" in terms of equipment - the minimums will be listed. The local authority may also require additional equipment in national regulations (like an ELT) depending upon the type of flight, so you gotta have that too.

So, if you're going to fly the 182 private VFR on a nice day, and the stormscope is not working, you're probably okay to go. It should be placarded inoperative.

You'll probably find that even the gyros and radios are not listed in the TCDS, and are options in the parts catalog for many light aircraft. Again, if they are not required for the intended flight, and they are placarded inop, or otherwise secured, you're good to go. But, as post #2 says, there are some minimums for any powered plane - not optional.

Interestingly, the TCDS can list some unexpected items; For the C 182, the stall warning system has to work. and if that placard which says: "Maximum baggge weight 120 pounds" shrivels up, and falls off the inside of the door, the aircraft is not airworthy (until you get out your felt tip pen).

It's the pilot's responsibility to understand what equipment is required to be operative for the flight. The answer will always be the most restrictive of those stated in a number of publications. The national regulations are easy to find, and usually apply to all the aircraft of a class. Once that's covered, TCDS, flight manual, and parts catalog.....


So a defect in any piece of equipment whose proper functioning is not mentioned as a condition or limitation in the flight manual is not unairworthy, as a matter of law.

This leads to interesting consequences - for example, an aircraft with a broken elevator is still, as a matter of law, airworthy.



I disagree. I gotta say that broken elevator = not "safe" in anyone's opinion = not airworthy. But, if that is not convincing enough, how about the TCDS for the 182 which states: "

Control surface movements Wing flaps Down 38° +0°, -1°
Elevator tab Up 24° ± 2° Down 15° ± 1°
Ailerons Up 20° ± 2° Down 15° ± 2°
Elevator Up 28° ± 1° Down 21° ± 1°
(Relative to stabilizer)
Rudder: Right: 24° +0°, -1° Left: 24° +0°, -

That would be all of both elevators, just to clarify. If any part of either elevator is not doing this, that aircraft is not conforming, so not airworthy.

If the enforcement people suspect that you are flying unsafe and unairworthy, they will be able to articulate this with reference to the regulations, and design data for that aircraft. They know the law....

[172driver]

Admit to only having skimmed the thread, but

I don't know of any piston GA plane which has an MEL.

the 172RG I mostly fly definitely has one.

[Contacttower]

the 172RG I mostly fly definitely has one.

Is there a difference between what most light aircraft have (outlined below) and a MEL like one would have in a larger aircraft? My understanding is that one is part of the POH but an MEL is something separate?

Just looking in the C182T's POH what it does have is a "Kinds of Operation Equipment List" which identifies the equipment required to be operational for airplane airworthiness in the listed kind of operations; Day VFR, Night IFR etc.

For example for day VFR the HSI does not need to be functional but for IFR it does...

[BillieBob]

So a defect in any piece of equipment whose proper functioning is not mentioned as a condition or limitation in the flight manual is not unairworthy, as a matter of law.That is true so long as the aircraft continues to meet the relevant certification standards on which the Certificate of Airworthiness was issued. A failure to meet those certification standards voids the Certificate of Airworthiness and the aircraft no longer complies with Article 16(7).

To determine the minimum equipment requirements for any aircraft it is necessary to consult the relevant Certification Standard, the Flight Manual and Schedules 4 & 5 of the ANO. Further requirements above the minima may be set, in specific cases, by an Operations Manual, which may also include an approved MEL.

[dont overfil]

Coincidentally a CAA e newsletter has popped up this morning with links to an FAA site on the very subject. Sorry I can't offer a link.

D.O.

[englishal]

Where in the POH does it say which equipment may be unserviceable for flight?
Regarding instruments, we have a table in our POH/AFM for the Commander which lists type of flight (i.e. VFR day, VFR night, IFR) and which instruments are required to be operational. It is similar to the list in the FARs and actually you don't require an awful lot of instruments to fly.

Off the top of my head, to fly day VFR you must have:

Oil temp - in the case of an air cooled engine
A means of determining the fuel onboard
Oil pressure
Altimeter
ASI
Compass
CHT

and that is about it.

For IFR you need some additional stuff, like a clock, and navigation aids suitable for the flight.

[Grob Queen]

Thankyou again everyone. I think I am getting a clearer picture wrt instrumentation now.

Thank you for your post Prof Reed. So am I to understand then, in simple speak that one can legally fly without some instruments. But SENSIBLY it is up to the pilot to make up his/her mind when checking the aircraft/type of flight/wx conditions etc etc?

PB and GW-i'm pleased to see that cross checking the compass and DI is normal practice and not jsut down to my being thick ;). I am taught FREEDA cx when about to make a visual recovery and after the A and B of "ABC" cx. My cx during flight are "FEEL" about every 10minutes (when I remember or when my instructor prods me :hmm:)

PB - Many thanks too for your detailed info on DIs, isogonals, prop pitch and Deviation. Thats really extremely helpful and explained in away that this "technical idiot" can understand! :)

We do indeed have a deviation card on the coaming, but we never use it!!!

GW - What are "UNOS?" Couldn't work that one out! I see what you mean about using the compass only.....my brains fried enough during a navex at the mo - but i'll get used to it...it is all part of the fun and challenge of flying after all! "CS" props, are they teh variable pitch type?

TVM GQ

We do not have the blue lever or MP in the Grob, but the Firefly dies indeed have such equipment

[thing]

Sounds an odd set up at your place GQ (I think I've said that before!). You ought to come up the road and see the stuff we fly. I reckon if we crushed them all together we'd get one serviceable a/c...There isn't an a/c on our fleet that doesn't have one fault (or several) at any one time.

[Grob Queen]

We may be odd thing, but its a damn good club to belong too :p We do have our problems...only today our engineer serviced one Grob, our other is having its bandy legs changed and has been u/s for a while, back on Monday, when the Firefly goes for its annual......

I really will come to you guys at some point (make that 5 minute flight when I'm qualified ;) ) but probably before!

[peterh337]

This thread rapidly got confused between flying without the legally required equipment, and operating in accordance with some kind of "MEL". The former is relevant to all aircraft (though what exactly is legally required is to be found in multiple sources; not in one easy place) but a formal MEL is found in larger aircraft, and in AOC ops of any aircraft.

[Gertrude the Wombat]

So am I to understand then, in simple speak that one can legally fly without some instruments. But SENSIBLY it is up to the pilot to make up his/her mind when checking the aircraft/type of flight/wx conditions etc etc?

Correct.

cross checking the compass and DI is normal practice

Correct.

[Pilot DAR]

So am I to understand then, in simple speak that one can legally fly without some instruments. But SENSIBLY it is up to the pilot to make up his/her mind when checking the aircraft/type of flight/wx conditions etc etc?



Well Grob Queen, close, but overly simplified.

The regulations don't always give the pilot room to use sense. Sometimes you just gotta read and follow the regulations....

The Canadian regulation for this situation reads:

605.10 (1) Where a minimum equipment list has not been approved in respect of the operator of an aircraft, no person shall conduct a take-off in the aircraft with equipment that is not serviceable or that has been removed, where that equipment is required by
(a) the standards of airworthiness that apply to day or night VFR or IFR flight, as applicable;
(b) any equipment list published by the aircraft manufacturer respecting aircraft equipment that is required for the intended flight;
(c) an air operator certificate, a private operator certificate, a special flight operations certificate or a flight training unit operating certificate;
(d) an airworthiness directive; or
(e) these Regulations.
(2) Where a minimum equipment list has not been approved in respect of the operator of an aircraft and the aircraft has equipment, other than the equipment required by subsection (1), that is not serviceable or that has been removed, no person shall conduct a take-off in the aircraft unless
(a) where the unserviceable equipment is not removed from the aircraft, it is isolated or secured so as not to constitute a hazard to any other aircraft system or to any person on board the aircraft;
(b) the appropriate placards are installed as required by the Aircraft Equipment and Maintenance Standards (http://www.tc.gc.ca/eng/civilaviation/regserv/cars/part6-standards-625-2451.htm); and
(c) an entry recording the actions referred to in paragraphs (a) and (b) is made in the journey log, as applicable.

Item 1(b) requires you to do some rather involved research, to be sure, and item 2 specifies some actions that must be taken if it is determined that flight is permitted without that equipment. The pilot is resonsible for not flying until these are done.

[BackPacker]

The other difference between the list in the POH of a light aircraft, and a full-blown MEL, is that the list in the POH is typically very simple and definitive: The equipment on the list needs to be there and function normally for the flight to be legal. Period.

A MEL, in contrast, is far more complex. For each of the items listed (and there are a LOT of items), it will specify the legality of the flight, and the mitigation measures to take if that item is U/S. And these mitigation measures may depend on the status of other items as well.

Here's a completely random example:
Flight Deck Fuel
Quantity Indicators
(Main Tanks)
Except for ER operations, one may be
inoperative provided:
a) All boost pumps in associated tank operate
normally,
b) Fuel flow meters operate normally,
c) Center tank indicator operates normally,
d) Flight crew periodically computes fuel
remaining, or checks fuel remaining against a
pre-computed fuel burn chart, and
e) Fuel quantity in associated main tank is
verified by an acceptable procedure.


Here's a list of master MELs from the FAA:

Flight Standards Information System (FSIMS) (http://fsims.faa.gov/PICResults.aspx?mode=Publication&doctype=MMEL)

[dont overfil]

Thanks BackPacker.
That's the one I wanted to post.

D.O.

[Sir Niall Dementia]

Try this one; it gets interesting from page 289!

http://www.easa.eu.int/rulemaking/docs/technical-publications/EASA_Part-M.pdf

I've heard a rumour from the CAA that ALL privately owned aircraft with a Public Transport Cat CofA that are also used in a public transport role (training, aerial photography, chartered to a flying club etc) are going to be required to have an MEL, Ghengis may be able to squeeze more from his contacts, all I've heard so far is the rumour.

One of the G550's I fly for a living is operated managed by us (an AOC holder) and flown privately for the owner and no-one else, under the CAM it is required to have an MEL, and our insurers wanted an MEL in place as well (we just gave it the same one as the other two aircraft)

When the CAA brought in MELs for AOC ops it was a nightmare, with little or no guidance, and long delays in getting approvals. I'd give good money to watch them trying to sort out the applications from a hundred different flying clubs, all with different ideas.

Thankfully my aeroplane is on a permit:ok:

[peterh337]

So many flying school planes have INOP kit, and this includes FTO planes and also includes planes operated under charter AOCs, that somebody will have fun mandating MELs for all these.

Or perhaps the declared equipment will not include the stuff that is INOP :) There is no legal requirement for an autopilot, for example, and e.g. the Islander ops did not even have them (INOP or not) for many years.

[DeeCee]

How do you know that? I have been a member of a few different clubs and I cannot recall any aeroplane with an inop instrument. Please justify that statement.

[Genghis the Engineer]

How do you know that? I have been a member of a few different clubs and I cannot recall any aeroplane with an inop instrument. Please justify that statement.

I think you've been very lucky, I've seen dozens.

I regularly fly two CofA aeroplanes one with a permanently U/S autopilot, and the other with a permanently U/S VOR. The first is within a flying school, the second a club based syndicate.


As a young Flight Test Gingerbeer circa 1996 I backseated (plenty to choose from!) an evaluation of a DC3 for a role in pollution dispersal spraying. In the way of these things, my test pilot was a US Navy F/A-18 driver (don't ask), as FTE, I sat in on the brief. Part of which was along these lines:

Company pilot: "And to put the gear up, we'll pump this, which is the standby pump - the main being u/s".

Test Pilot: "When the main system is serviceable, how do we do that?"

Company pilot: "You know, I've no idea. I've only been flying the aeroplane 4 years and haven't seen it serviceable yet."

G

[BillieBob]

I've heard a rumour from the CAA that ALL privately owned aircraft with a Public Transport Cat CofA that are also used in a public transport role (training, aerial photography, chartered to a flying club etc) are going to be required to have an MELApart from the fact that none of the activities that you mention comprise public transport - they are all aerial work - the CAA clearly have not read the requirements.

So far as training is concerned, EASA have made it very clear that this will be subject to Part-NCO or Part-NCC depending on the type of aircraft used and irrespective of whether the activity is commercial or not. Part-NCO, which covers all non-complex aircraft (as defined in the Basic Regulation) makes an MEL optional. All operations under Part-NCC (i.e. in complex motor powered aircraft) will require an approved MEL.

Commercial operations, other than flight training, will fall under Part-CAT or (in the case of aerial survey, crop-spraying, etc.) Part-SPO and will require an approved MEL

[DeeCee]

Maybe I've just been lucky, although I wasn't thinking of DC3s. I've been flying for over twenty years from Stapleford, Top Farm, White Waltham, Thruxton, Oxford, Headcorn and Lydd, and I honestly cannot recall an instrument that didn't work. Maybe I didn't notice..........

[peterh337]

Actually a lot of duff avionics are not placarded INOP.... most VFR pilots don't know how to use an autopilot anyway so putting a sticker on it just makes the owner look like he is too tight to fix it :)

[Jim59]

I've come to this thread rather late.

I would like to suggest that AIRCOM 2010/12, The Management and Recording of Aircraft Defects, makes relavant reading. See link below.

"The purpose of this AIRCOM is to provide clarification and guidance to EASA Part M requirements relating to the management and recording of aircraft defects and deferred defects."

What is clear that aircraft with defects may fly either with, or without an MEL but only if the defect is recorded and has been deferred by an appropriate person. The appropriate person depends on several factors including the type of defect. If a defect has been identified and not deferred then the aircraft is U/S - even if the defective e.g. instrument is not a required instrument.

This applies only to EASA aircraft - not Annex II etc. For some defects, in some circumstances, a pilot may defer a defect - in other cases it must be an engineer.

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

[Grob Queen]

Quote:
So am I to understand then, in simple speak that one can legally fly without some instruments. But SENSIBLY it is up to the pilot to make up his/her mind when checking the aircraft/type of flight/wx conditions etc etc?

Well Grob Queen, close, but overly simplified.

Thanks PilotDAR. I now have the gist of "to fly or not to fly" with U/S instruments. i think I need to talk to our Cub Engineer to discuss our particular case (although as I said, I have not yet seen any u/s stickers on our instruments when the aircraft are airworthy! ) :)

[Dave Gittins]

Just to add another comment .... I was reading the Flying Order Book yesterday and that has a list of things without which the aeroplane may be flown.

Genghis ... that sounds like a story from Martha Lunken.

[Grob Queen]

Thanks Dave,
I have read (oh well, ok then, skimmed through!) our Flying Order Book. I'll ahev a closer read next time rain/fog/wind stops play! :)

GQ

[GeeWhizz]

Sorry for the late response GQ, busy busy these days!

UNOS: Undershoot North Overshoot South.

Its a way of remembering compass turns. DIs are stable in comparison to the compass and so when in a turn its easy to roll out on your desired heading. If flying by the wiggly compass we need to undershoot the desired heading if flying through North, and overershoot the heading if flying through South. Its to do with lag and the construction of the compass i.e. being weighted to be level in its case in accordance with latitude. (or at least that's my understanding anyway.)

GW

Edit: What a &%ck!!! Thank Mcgoo... think its sorted now! :O

[mcgoo]

Try again GeeWhizz! :E

[Grob Queen]

TVM as ever GW!
Aah, thats what my instructor means then when after we have turned, he says wait for the compass to settle before realigning the DI!

[Gertrude the Wombat]

Try again GeeWhizz!
Yes well, I have found that for me personally it's easier to forget trying to remember all that stuff and just do timed turns.

Hmm ... how do you do those on a G1000 aircraft where you lose the timer if the screens go blank ... gosh, an actual reason to have a real watch with you in the cockpit!

[peterh337]

I never remembered the compass turning rules. Not for the UK PPL, not for the FAA PPL, not for the FAA CPL, not for the FAA or JAA IRs. A complete waste of time IMHO.

Timed turns are far better, and even if you count in your head they are more accurate than trying to second guess what the compass is doing. And e.g. a vertical card compass swings very differently to a standard compass. My VC compass is almost unguessable.

[bookworm]

On the other hand, EU OPS for non-commercial operations says

A flight shall not be commenced when any of the aeroplane instruments, items of equipment or functions required for the intended flight are inoperative or missing

(my bold). It says required. Not installed, required. If they meant installed, they surely would have said so?

And if they'd said "installed", I'd still be in the Ottoplatz. ;) I'd be lying if I said that I thought the precise phrasing of NCO.IDE.A.105 got more attention there that it has got in this thread. But the intention is that equipment required by Part-NCO or by the AFM is operative.

Thanks to Jim59, by the way. I'd never seen AIRCOM 2010/12 before and it is helpful.