Snags

[Essel]

Can anyone help me understand if there is a basic level of minimum functioning equipment and instrumentation required of private aircraft, from a regulatory and/or legal perspective? I refer to SEP (Land) aircraft.

Or is it purely a question of being certified airworthy?

I am specifcially wondering about situations where the aicraft has, for example, a CofA but has a unserviceable stall warning alarm.

Thanks

[BackPacker]

AFAIK the only thing that's required by law for private aircraft, day VFR is an altimeter, compass and airspeed indicator.

However, there are certification requirements for aircraft as well and these may lead to additional equipment. If so, then that's listed in the POH. Since the POH is the basis for the CofA, if the POH says something is required, then it's a no-go item if it's not serviceable.

I would imagine that aircraft who show a distinctive buffet before the stall, and have conventional stall characteristics, would not need a stall warner per se. But if there's no aerodynamic stall warning or otherwise, and nasty stall characteristics, a stall warner would be required.

[Keygrip]

An interesting avenue depends on your interpretation of the CofA.

I don't have the exact wording to hand, but know that at least some in the FAA stress that the CofA is issued to an aircraft and is valid only whilst the aircraft *meets its design approval*

So if it was *designed* and certificated (certified) with a particular item, then it must have that particular item, in working order, at the time of flight.

They even took this down to the level of screws in cowlings and the little hinged canopy holder that one finds under the engine cowling of a new PA28. Even the stickers by the fuel tanks filler caps. If it was designed by the manufacturer to have them - then it must have them or the CofA is invalid by definition.

If you are talking about a UK aircraft, you could always look in the Air Navigation Order of course - but you knew that anyway.

[Fright Level]

In the commercial world, airlines use a Configuration Deviation List (CDL) and Minimum Equipment List (MEL) to ensure the legality of a flight with missing/defective items.

The general philosophy is that the aircraft can take off with defects provided the systems are never degraded below that required by the CAA for type certification.

A CDL/MEL never mentions items that are always required (eg wings, engines, landing gear etc) and items that don't affect airworthiness like carpets or pen holders.

Other items are then catalogued on whether they may be needed for a particular flight, so if your NAV radio is broken and you are flying VFR in VMC then there would be no need for the radio to work.

There is some useful information in CAP747 Mandatory Requirements for Airworthiness (http://www.caa.co.uk/docs/33/CAP747.PDF).

[mad_jock]

The UK uses the FAA MMEL for SEP fixed wing aircraft and its a right ball ache to find on the web.

As for your problems with the stall warner I should imagine about 50% of the training cessna's in the UK suffer from what could be call stall warner failure.

Its not really failed its just old and crap linked with bent airframes gives a pathetic strangled honk if your lucky to get anything instead of a decent honk. If its a C170 it's maybe just not stalling. The one I used to fly didn't unless you g loaded by doing some that isn't taught in the PPL. For a level power off stall the ASI used to read zero there was no buffet no nose drop it just wafted down with full control back at about 600ft/min it was a bugger to land as well until you got the knack of dropping it.

And for the people who say you have to suck on the hooter before every flight you are welcome to getting half a kilo of midges in your mouth. And putting a hanky over the top does nothing to prevent coughing for the first half hour of the lesson be it student or instructor who gives it a suck. And even if it makes a noise on the ground experence has shown that doesn't mean it will work in the air.

If you tell us the type we can give a bit more help some types its a bit more vital they work eg PA38

[DeeCee]

I had to make a precautionery landing in a PA28 once when the temperature went off the scale. Turned out to be a half stuck carb heat cable (this was a very hot day). The aircraft was snagged whilst they found out the cause.

[Pilot DAR]

Essel,

The foregoing is good information... To add to it, light aircraft do not come with MEL's (probably because there is no requirement for one, and people are not willing to pay the cost to create it). So, what does a pilot do when an unserviceable item is found? It's up to the pilot to judge, which puts a lot of responsibility on that pilot. Yes, the regulations specify certain minimum equipment, and you must not depart without it. Unfortunately, those lists are not together, and can be hard to sum up. If you miss one, it's your fault.

So, what I do is consider the situation the other way around. If I crash the plane, and the absence of item "X" is in any way the cause, would I still be confident to explain to the authorities, and the insurance adjuster what I was doing flying the plane in that condition? How serious would the accident be, if the missing equipment were a cause?

If I depart for an intended day only flight knowing that the nav lights are U/S, I think that most of us would be okay with that. If I continue into night, and have a mid air, it's all different.

Stall warning system? I wouldn't! If you had any kind of landing mishap, that's probably what would get the blame, then you, for choosing to fly that way. I did knowingly test fly a Cessna 185 some time ago with a U/S stall warning horn, only to find afterward that the Type Certificate Data Sheet (the bible for that plane) specifically says that the horn must be functional. I would have never thought to look there for "MEL" information! To make matters worse, I had allowed someone else to load the plane for the test (too much trust) and I later found that the C of G at gross weight was 1" behind the aft limit!

If I'd crashed it, I would have had a very hard time explaining why I chose to fly it that way! You take on a lot of responsibility choosing to fly a less than servicable aircraft, make sure it's worth the risk. It's probably better to have the owner fix the plane. He's expected to anyway!

Pilot DAR

[SNS3Guppy]

Aircraft airworthiness can be broken down into two basic parts. What's legal, and what's safe. Both must be satisfied in order for an aircraft to be considered airworthy.

To be legal, an aircraft must be in conformity to it's type certification, modified type certification (by a supplemental type certificate), or by another manner which has been deemed acceptable and legal. Certain operations with inoperative equipment addressed by a Minimum Equipment List, Configuration Deviation List, or other such means are one such example. Some aircraft manufacturers publish in the aircraft operating handbook a list of installed equipment and guidelines as to what must be functional and what can be inoperative and still be in compliance with the airworthiness certificate.

When an item is inoperative, a general guideline is that it must be deactivated, and the means of doing this vary with the equipment and the regulations under which it's operated. This may mean pulling a circuit breaker. It often means placarding the particular item as inoperative. It may mean deactivating or placarding a control...and it may require the signoff or attention of a mechanic (engineer).

Once the legality of the item is satisfied, then one must also ensure that the change is unsafe. One may be legal to operate without flaps, for example, but given the nature of the flying one undertakes (short, slick icy air field, for example), one might not be safe to operate without the flaps.

Your stall warning is inoperative...but are you safe to operate that way, and are you legal to do so? Is the stall warning required by the type certification of the airplane? How do you know? In a nutshell, you should have an equipment list or a furnishings list in the aircraft flight manual, and this will list everything put aboard during certification and production. You may find this in the weight and balance section of some airplanes. If it's part of the aircraft as certified, then it needs to be installed and functioning, or some other form of relief must be provided. Once you've settled the question as to whether you're legal, you need to determine if you're safe.

This really depends on the airplane. You may be flying an airplane which provides ample physical indications of a stall, and can fly just as easily without the stall warning. Or you might be flying an airpalne which simply quits flying and rolls over on you...some do that, and provide precious little warning about a stall. Do it in an accelerated conditions, such as in a steep turn, and you may find that it doesn't take very much lack of coordination on the rudder, before the airpalne rolls out over the top or tucks in underneath and bites you. In this case, you may find that operating with the stall warning inoperative isn't safe.

Remember, it has to be safe and legal to go fly.

I don't know about the UK regulation, but the US regulation spells out exactly what minimum instrumentation is required for a particular type of operation. This may be day VFR, for example, or night IFR. This requirement is entirely independent of what the specific airplane may require. That is, you need to meet the requirements of both regulations...both what the aircraft certification requires, and what the FAA or CAA regulations require. If you're flying an aircraft of a different nationalities registration, then you may need to be in compliance with multiple types of regulation.

It's important to realize that when you're handicapped by inoperative equipment, you are also subject to much bigger handicaps if something else goes wrong. Some of it may surprise you...you need to play a game of "what if" with yourself to determine not only the ramifications of the inoperative instruments or equipment you have now, but what you might have if something else fails...and plan for that as well, in order to be safe.

For example, I fly a multi engine airplane that uses hydraulic pumps. It's got redundance with engine driven pumps, air driven pumps, and electric pumps. If I've got an air pump out, then I've still got the others. Not too long ago I left Sheffield airport (I think...Robin Hood field, was it?), and had that very problem...one of the pumps split a case. We deactivated it...now it was legal. However, if the other pump failed, we'd lose our ability to raise our landing gear. If that happened then we also had a reduced climb performance. It also meant a flap problem if we had to come back and land, so we had to consider our increased landing distance, and so on. More than meets the eye...you may have more impacted by the loss of a vacum pump, for example than you think

A vacum pump...so you lose your instruments. It's day, VFR. Not a problem. But you're enroute, and have to divert, and suddenly it's getting dark. You'll get back before dark, but today there are a lot of clouds forming on the horizon, and they cause it to get darker sooner, and now you're looking at flying home on a tipped attitude indicator, a failed turn and bank indicator, and a heading indicator that continuously gives wrong information. This by itself might not be a problem, but couple the fact that you don't have the useable instruments to the fact that you have instruments giving misleading, false indications, and you could have a dangerous situation.

The battery starts to die enroute. You can fly home becuase the engine will keep running with or without the battery...you know this. You also know if you land you can always hand prop the airplane...so getting from A to B shouldn't be a problem. However, do you know why the battery died? Do you have a short somewhere that could turn into a fire? What if you have an engine failure and need that battery in flight to restart the engine? What if you have an emergency that requires the use of the battery to operate a radio? How about lowering landing gear, or operating lights or a beacon, should it develop into the first situation...diversion, getting late, getting dark...etc?

You can see that a simple problem can compound itself shortly...the inoperative item itself may be the least of your worries, particularly if other factors develop. Look not only at the inoperative item and your planned flight, but at the inoperative item and the unplanned things that could complicate your planned flight. This is part of the "is it safe" equation in the two part decision regarding airworthiness.

It's always two things: is it legal, and is it safe? Unless the answer to both those questions is a resounding "yes," then the flight should not be undertaken.

[Essel]

This is superb. I'm reading and taking it all in guys, thanks very much for the explanations and advice so far. I'm just about to get the POH and check what it says. "Standby"!

Ok. The POH does not list the Stall Warner in the basic instrument list in the W&B sheet, but this list relates to items which are relevant to the stated weight; I assume.

The Stall Warner is stated in the "Operating Limits" section which comprises the following sections:
a) Approval Critera
b) Limiting Speeds
c) ASI Markings
d) Stall Warning
e) Design Load Factors at Max AUW
f) Max. AUW.
g) GC Limits.
h) Loading Limitations.

in part d) Stall Warning. It simply states the Warner will sound 5 to 10kts before Stall.

So, from this, do I conclude the CofA in invalid if the Stall Warning is U/S??

[Mike Cross]

For IFR don't forget the TSO'd Pencil. (http://www.rst-engr.com/rst/articles/tsodpencil.pdf)

Mike

[Islander2]

Pilot DAR said:
To add to it, light aircraft do not come with MEL's (probably because there is no requirement for one, and people are not willing to pay the cost to create it). So, what does a pilot do when an unserviceable item is found? It's up to the pilot to judge, which puts a lot of responsibility on that pilot.Not quite true, some do have the equivalent under the heading of 'Kind of Operations Equipment List' or similar in the Limitations section of the POH. The list in the POH for my Bonanza runs to three pages and covers all of the systems and equipment upon which type certification for each kind of operation (VFR Day, VFR Night, IFR Day, IFR Night) was predicated (some fifty items in total). It is prefaced with:

"The systems and equipment listed must be installed and operable for the particular kind of operation indicated unless:
1. The airplane is operated in accordance with a current Minimum Equipment List (MEL) issued by the FAA; or
2. An alternative procedure is provided in the Pilot's Operating Handbook and FAA Approved Flight Manual for the inoperative state of the listed equipment.
Numbers in the Kinds of Operation Equipment List refer to quantities to be operative for the specified condition. The list does not include all equipment that may be required by specific operating rules. It also does not include components obviously required for the airplane to be airworthy, such as wings, empennage, engine, etc."

And for the Bonanza, an operable stall warning horn is listed as mandatory for all four kinds of operations.

[Karl Bamforth]

Essel
if you tell us what aircraft you are asking about someone will have the answer.

I think SNS3 covered it very well as he always does.

What is safe and what is legal.
In the UK there is no requirement to have an anti-collision beacon fitted. But if you do have one fitted it must work.

In day VFR working or not it is quite useless but would be illegal to take off with it inop.

I suspect that if someone approached a pilot after a flight and informed him that he was flying illegally because the ant-coll did not work his reply would be It did on the preflight :ok::ok::ok:

Edit

Just had a thought, if fitted it must work, but I am not sure that you are legally required to turn it on.

[Essel]

Its a Robin HR100/200B.

[Keygrip]

light aircraft do not come with MEL's

I used to fly various Seneca V in Arizona - which most certainly *did* have an MEL (that's the aircraft - not Arizona).

[SNS3Guppy]

Anybody can make, and have approved, a minimum equipment list (MEL). Few do this without first going to a Master Minimum Equipment List (MMEL) maintained by the FAA (with respect to N registered equipment). A MEL can be developed with or without an existing MMEL...but generally operators are loathe to do so because of the work involved, and because of liability concerns. The MMEL represents preapproved material; drawing from this material short cuts the process considerably.

Most light airplanes have no MMEL. It's important to understand that MMEL or not, a MEL is aircraft specific; it's approved for a specific aircraft, or specific aircrafts. It's not issued for all Cessna 310's, for example...but for NXXXXX...the specific registration and serial number, and is applicable to just that airplane (or a fleet or airplanes attached to that particular MEL, where applicable).

When the MEL is in use, it plays the same role as a supplemental type certificate, modifing the condition of the aircraft in an approved manner.

[hatzflyer]

Essel, in your original post you ask about a SEP.You do go on to stipulate operating on a Cof A.
Its interesting to note ,not ALL SEP,s operate on a CofA.
On a permit A/C there is no requirement for a stall warner unless the aircraft displays nasty stall habits.
I dont see much on here about permit aircraft but would urge you to consider them.
Mine cruises at 180mph tops out over 200mph climbs at 3000fpm and costs a fraction of the Robin costs :ok:to run!
Check out the Light Aircraft Association!
Cheers John.

[Essel]

I dont see much on here about permit aircraft but would urge you to consider them.
Mine cruises at 180mph tops out over 200mph climbs at 3000fpm and costs a fraction

Until the wings snap off as they were not glued on properly ;-)

I do see your point however.

[englishal]

As for your problems with the stall warner I should imagine about 50% of the training cessna's in the UK suffer from what could be call stall warner failure.
I don't have a stall warner, but do have a CofA!;)

[Pilot DAR]

Not all aircraft were designed with, or are required to have, a stall warning system. However, I would suspect that those which were never fitted with that system are "older" types, as I think that just about all "newer" certified aircraft have a stall warning system. I have no idea about the Robin.

If the aircraft has a stall warning system, that system was certainly used as a part of the showing of design compliance for the certification of the aircraft. Therefore flying with the system inoperative would be a violation of the basis of certification, and require a design approval (STC) to permit that operation.

A flashing beakon, on the other hand, might be required by operational rules, but is not required for a showing of design compliance (for the basic design in DAY flight), and therefore does not need to be fitted, or if fitted, operational, unless an operational rule says so, because the design does not. If the aircraft manufacturer required that a beakon be operational on the aircraft, it would likely be stated in the Type Certificate Data Sheet, as are many other fixed requirements.

Safe and legal. Safe is pretty clear. Legal will come from a number of different sides, and you have to cover them all.

Pilot DAR

[hatzflyer]

Essel,I think a little research will soon prove Vans Aircraft have had a lot less problems with wings than Robin have!( mind you niether has a perfect record although Vans problems are mainly pilot induced overstress whereas Robins are manufacturing faults ).