Simple, really... what's the MSA over the sea?

If you wanted to let down to an airfield on the coast without an IAP, and could let down over the sea, how low could you legally go? (Ignore for the moment the question of the legality of home-made IAPs, which might or might not be safer but where descent below MSA is involved - that's a separate argument.)

Do the charts as usual show all obstacles above 300ft?

Tim

I'd say 1000' AMSL if no rigs etc. marked on the chart...

Andy

As long as the waves dont lap over the windscreen. ...... Seawater is havoc on the aluminium!:p

1500 feet (at least that is what is used by the North Sea Helicopter companies). And to descend below that requires a CAA approved self interpreted radar approach.

It is not so much the fixed obstacles (although wind turbines are sprouting up daily) but the moving ones that are of concern. Most (but not all) vessels that you can expect in British waters will be below 500 feet high. But it is not uncommon for Mobile Offshore Drilling Units to be towed around the coasts of NW Europe and they will be around 500' high. There are also a couple of crane barges that visit the North Sea from time to time with 200m long booms. It is an amazing sight to see them sticking out of the top of sea fog.

1500 feet (at least that is what is used by the North Sea Helicopter companies). And to descend below that requires a CAA approved self interpreted radar approach.

Boomerangben,

1500ft? Are you sure? Its just that my experience as pax in the North Sea would definitely say more like 500ft, or even less.....can you expand on the 'self interpreted radar approach' bit, as I am constantly amazed at the crappy weather that does not seem to stop the choppers flying.

If you are a chopper pilot in the North Sea, I have a question: Have "recently" been working in the dutch sector...How come the Schreiner guys "always" seem to be grounded due wx, when you can hear the Bristows boys happily flying around over the Radio? Is it Type/Equipment? Company Regs? Registration issues re.G/PH?

Regards, SD..

PS : Always amazed at the weird nature of sea fog, it is spooky and beautiful at the same time to see dense fog surround the rig yet see the top of the legs and derrick bathed in sunshine and see just the derricks/cranes/legs of other rigs jutting up from the milky layer once above it.....and hopefully on the way home.....

FAR 97.3

(i) MSA means minimum safe altitude, an emergency altitude expressed in feet above mean sea level, which provides 1,000 feet clearance over all obstructions in that sector within 25 miles of the facility on which the procedure is based (LOM in ILS procedures).

So at least 1000ft.

Surely, for VFR, there is no lower limit. You can legally fly down to the surface. You have to keep 500ft away from man made objects - the usual thing.

For IFR, it's 1000ft as usual - unless taking off or landing and then no limit applies.

Thanks all - yes, Boomerangben, that's rather what I'd suspected, i.e. the moving obstacles would be the problem. As I was definitely talking about IFR-VFR transition then that would be an issue.

So in practice an IFR letdown at a nearby suitably equipped airfield followed by low-level VFR to destination is the way forwards, as this would allow me down to <1000ft.

Tim

The remark about VFR vs IFR is interesting - an important part of IFR which is often not used....below 3000' clear of cloud you are exempt from 1000' above the highest object - therefore if flying in VMC under IFR or VFR the height you can legally fly at is the same.

(as an aside - it is also often misunderstood that once above 3000' it is very easy for the average pilot to become IMC even though they are actually flying *visually*.)

The only difference therefore is IMC on an instrument approach. Minima are defined by the procedure and personnel licensing (IMC/IR). Additionally you have the approach ban as well.

However, I havent ever really investigated the legality of descending below MSA on an unpublished approach...I personnally would have thought that it wasnt allowable - but I cant remember if there is an exemption for an approach - I will certainly check the wording in UK AIM tonight!!!

Just a thought but as we are talking MSA the fact its over the sea is not entirely relevent - as the landfall would be within the catchment area for MSA calculation.

Additionally NOTHING below 300' makes it onto our charts - that is not just 300' agl but 300' asl!!! Thus making it at least 1300' agl - even over the sea, as you would have to allow for an object up to 299' on the beach, or 1mile out...

This is going to start another long thread, so I am getting out of here after posting this, but...

However, I havent ever really investigated the legality of descending below MSA on an unpublished approach...I personnally would have thought that it wasnt allowable

is incorrect. In the UK there is no rule against a DIY instrument approach.

Whether it is wise in a given location, etc, is a separate issue.

MEF from charts + 1000ft if you must.

Flying to a place with a proper IAP and then either a VFR transit to your intended destination if possible or land at the place with the IAP if VFR transit not possible.

You can then ring UV to see if he can organise a free landing fee for you.

:} :}

I concur with IO540. Good job, because I have seen a/c appearing out of the murk at often enough at Blackbushe (successfully and without drama too).

I0540 states...>In the UK there is no rule against a DIY instrument approach. <

Well thats a matter of opinion - this was debated in another thread - take a look at:-


DIY Instrument Approaches (http://www.pprune.org/forums/showthread.php?s=&threadid=167880)

Why not have a word with someone who does it on a regular basis.
The best example I can think of is Loganair, who do the Glasgow - Barra schedule service in the DHC6 (twin otter).
I flew on the service about once a month for two years, and we often had to an instrument let down over the sea to land on the beach.
Minima's were quite strict and adhered to like glue, the pilots often stated that the biggest problem was spatial orientation when you broke out of cloud and still had a lot of sea in front of you.
That, in my opinion is the biggest single factor to bear in mind when doing a cloud break over sea as opposed to over land.

I'm sorry, I've lost touch with all the people I used to know in Loganair, but I'm pretty sure that their Ops are still based in Glasgow, and an internet search will get you a number.
They always were a very friendly and highly professional bunch, and I'm sure they'll do their best to help.

NikNak,

Generally, commercial operators are allowed to operate outside of the normal rules of the ANO if their CAA issued operators certificate permits the exemption or provides additional flexibility.

In the UK where IFR and VFR merge into some strange condition when in Class G, the rule you have to watch is the 500' rule, so assuming over the sea, then 500' would be a safe minimum. You could in theory go lower, so long as you don't end up within 500' of anyone.....Even this may not be applicable if you're landing, I can't remember.

Well I've been acting pax in a Yak at 50 feet above the North Sea so... :E

Cheers, Jack.

Whilst Loganair can be acknowledged as experts in making approaches in poor weather, it should be remembered that they have lost a couple of aircraft and crews over the last 10 years; once descending over the sea to get visual on one of their discrete approach procedures, and once over land attempting to get visual on a base leg join in poor weather.

Even if it is legal, it doesn't mean it is safe if even the experts get it wrong.

Not so, I'm afraid, Englishal - not in my copy of the ANO, anyway...

28 (1) In relation to flights within controlled airspace rules 29, 31 and 32 shall be the Instrument Flight Rules.
(2) In relation to flights outside controlled airspace rules 29 and 30 shall be the Instrument Flight Rules.

Minimum height
29 Without prejudice to the provisions of rule 5, in order to comply with the Instrument Flight Rules an aircraft shall not fly at a height of less than 1000 feet above the highest obstacle within a distance of 5 nautical miles of the aircraft unless:
(a) it is necessary for the aircraft to do so in order to take of or land;
(b) the aircraft is flying on a route notified for the purposes of this rule;
(c) the aircraft has been otherwise authorised by the competent authority; or
(d) the aircraft is flying at an altitude not exceeding 3000 feet above mean sea level and
remains clear of cloud and in sight of the surface.

29(a) is the authority for unapproved instrument approaches (unless you want to quibble about 'necessary'); but otherwise 28 makes it clear 29 does apply outside CAS assuming you are IMC. If you are VMC below 3000ft then you can go lower - but that wasn't the point of the original question.

Tim

it is necessary for the aircraft to do so in order to take of or land;
The way I'd view it is that if you're landing IFR, 29(a) applies, so you can come down to whatever. As soon as you become VMC and you're not really on a published IAP, you can't really be IFR, therefore the VFR rules apply, notably the 500' rule. This is stated in

Without prejudice to the provisions of rule 5

Yes, but the 500ft rule doesn't apply to approaches to land, even at unlicensed airfields.

Tim

Skydriller,

I am not current on the North Sea at the moment and have never flown front seat in the Dutch Sector (although I have been a pax there once or twice) so I can't comment why one company flies when the other doesn't. I am not sure that it is appropriate to describe a company specific approach procedure on a public forum.

I agree with McMurphy. What might be legal may not be safe. I don't see anything wrong with descending to MSA (and I stand by an MSA of 1500') to break cloud. But how many private/GA pilots have the equipment (radalt, radar, audio/visual alerting device, autopilot etc), training and experience that commercial aviation deems necessary to carry out these approaches safely? It is far easier to become spatially disorientated over water than over land. 500' over the sea is not the place to get the leans either.

There is also the approach ban to considder whan making an approach to land i.e. you can not descend lower than 1000ft above the runway unless the minima are above the landing minima.

On a home made approach to an airfield with no met observer, how can you tell what the actual weather is below the cloud you are about to descend into?

Thus unless you can see the weather for yourself i.e. you are below cloud and can assess the visibility by 1000ft you are caught by the approach ban and can't realy even start the approach.

Regards,

DFC

On a home made approach to an airfield with no met observer, how can you tell what the actual weather is below the cloud you are about to descend into?

You descend and look?

You descend and look?
That's another coffee meets monitor experience :D

Thus unless you can see the weather for yourself i.e. you are below cloud and can assess the visibility by 1000ft you are caught by the approach ban and can't realy even start the approach.
Only applies to published IAPs.

Approach bans are stupid things anyway, why not have a go, if you can't get in, go missed and divert......Or maybe this is too much for some people....

You descend and look?

So how low do you go?;)

Depends what the weathers like :)

Someone mentioned a radar altimeter.

On "private" instrument approaches, are the CAA-authorised operators required to use a radalt? That would seem most unusual. Even Cat 2 and Cat 3 approaches do not require the pilot to look at the radalt. The autopilot sure uses a radar altimeter to do the last stage of an autoland approach, but on any manual approach the pilot still uses the standard altimeter for the DA decision.

A radalt would be extremely handy for DIY approaches though.

The radalt is of more use over the sea especially when there is no one to give you a QNH (although most platforms provide a QNH). More importantly though is that the RADALT feeds the audio/visual alerting device.

Although a radalt wont stop you hitting the cliffs....after all it only looks down...:ouch:

Exactly why you need a radar as well.

aha. Found it! Here is the authorities word on unpublished approach minima...

From UK AIP AD 1.1.18

11 Aerodromes without published Instrument Approach Procedures

For an aircraft landing at an aerodrome without an instrument approach procedure either:
a A descent should be made in VMC until in visual contact with the ground, then fly to the destination;
b An IAP at a nearby aerodrome should be flown and proceed as in (a); or
c If neither (a) nor (b) is possible, first obtain an accurate fix and then descend not lower than 1000 ft above the highest
obstacle within 5 nm (8 km) of the aircraft. If visual contact (as at (a) above) has not been established at this height, the
aircraft should divert to a suitable alternate with a published instrument approach procedure.


Again note - 1000' above highest obstacle - so even over the sea - as I said - you are looking at 1300' AGL (well AMSL if you are talking about let down over the sea but lets face it that means you must be nowhere near land - so if you go anywhere near land you are actually looking at 1400' AMSL as a minimum)...

FF,

I see your logic for the 1300', but charts do not show moving objects that are more than 300' above sea level.

Absolutely. Thats why I said as a minimum...

Its an interesting thought though isnt it - does that mean a moving object over the sea > 300' should be NOTAMd?

A curious thought isnt it - how can we pilots ensure our safety if we have not been presented with all the information we need...Id love for someone at the CAA to comment about the consideration of moving object hazards whilst engaged in overwater flight... :confused: :confused:

With a rad alt, one needs to know the terrain over which one is going to use it. That is why many aerodromes where precision approaches are provided produce a precision approach terrain chart which allows one to check the relative elevation of the terrain under the approach close to the runway and base any rad alt minima on that.

Over the sea depending on the type of rad alt system there can be some error caused by the movement of the waves and doppler effect.

When it comes to obstacles, all obstacles within the FIR whuch are 100m or more above the surface are required to be included in the AIP ENR 5.4 That includes mobile obstacles.

Any obstacle (including a mobile one) not included in the AIP is NOTAMed and there are a few each year where rigs are known to be moving about the place.

However and perhaps the more maritime among us can comment on this - beyond the 3nm mile limit? (from the coast) as far a vessels are concerned they are on the "high seas" and don't have to tell anyone who they are where they are or what they are up to. This would seem to make it difficult to determine exactly where those obstacles are.

Of course one could be letting down in the middle of the channel and pop out head on to a small naval boat launching a missile at what it sees as a hostile attack!

Taking that last unfortunate point perhaps when "bending the rules" these days we should think of the (unexpected) wider implications. e.g. why does that guy pop out of cloud low over the sea when he could make a normal approach at xyz - might be up to no good!

Regards,

DFC

FF

The AIP is not the law. Only the ANO is the law (in this context).

Also, phrases like "first obtain an accurate fix" are a give-away that this is an informal piece. What is an "accurate" fix??

If you have enough time to thumb through every piece of paper that's ever emanated from the CAA (AIP, AIC, all the wonderful differently coloured supplements like Pink and Mauve) you can find just about anything. You will find something that makes GPS illegal, if you look hard enough.

Incidentally, a radar altimeter does look slightly foward.

I didnt say it was the law...only that it was the authorities word on the matter. There is much in the AIP which is not encapsulated in the ANO yet we comply with it. But thats not the point.

Consider this..Given the statement in the UK AIP, following an accident of any description where the pilot did not follow this 'advice' or whatever you wish to call it - what would you expect a court decision to come up with - personally I wouldnt like to call it - it could go either way.

In all cases unless the person in question was in receipt of a radar service Im sure his airmanship would be called into question...and whilst he might not have broken any law would you (given the advice from the authorities) possibly consider his actions to be reckless or negligent given that such advice was for a completely different set of actions? Would you have considered that the commander had placed his aircraft in danger?

If so then you have broken laws...(re articles of the ANO about such actions)

These threads just run and run. Luckily, there isn't much data on what happens in bodged DIY IAPs.

Graham Hill was one, apparently. That one went badly wrong in the courts; I gather from an old timer who was familiar with the case that his IMCR had expired. Is the report online anywhere? That would put it clearly "out". But in those days a lot of planes, including airliners, were flying into terrain. Today, there is no excuse because even the cheapest GPS tells you where you are exactly, some 99.99% of the time.

In the absence of licensing/airworthiness issues, insurance will pay out in a case of negligence. That's covered by insurance. Not much use to the pilot because a bodged IAP (DIY or official) is likely to result in a CFIT and they are usually fatal. But it could affect whether passenger claims exhaust the 3P cover and hit the pilot's estate.

Not always fatal though; I know of one where he survived and there wasn't any legal drama. He did a GPS based IAP with no supporting position fix, among terrain. But what got him was not the descent, it was the lack of a missed approach procedure.

So, what seems to matter in these things is not CAA action (especially as the pilot is likely to be dead) but insurance issues. And insurance does cover negligence - up to the numerical limit of the cover.

All in all, not enough to go on and just as well!

IFR, one has to stay at the MSA unless landing and then how low can one go? I would do 700ft AGL over fairly flat country, with a position fix via two independent methods, plus current QNH and altimeter verified (for gross error) against an IFR GPS. Or 500ft over the sea. Otherwise, a low level letdown (radar based, obviously). The trouble is that a low level letdown is that they will take you down only to 1000ft AGL anyway. All that does is that it supposedly eliminates obstacles that you didn't spot on the chart, but you are trusting the ATCO completely for terrain clearance because he is giving you vectors and expects you to fly them.

More important, IMV, is to establish the cloudbase in the area. If a nearby unit gives it as OVC003 there is no point in trying anything. Perhaps a really experienced ex-mil low flyer could do OVC003 over water, to land on a runway which is right on the coast. If the whole area is around BKN010 and it is fairly flat, that should be perfectly safe for a DIY descent using a double position fix, and this is over the sea also.

Just my 2p. You have a point but the CAA are just AN authority on what is safe, not the final authority. Given no FDR/CVR one usually cannot establish what really happened anyway. They couldn't prosecute a dead pilot; they could offer an opinion in an insurance argument. A lot of what the CAA have written (for GA consumption) is bunk, especially on slightly modern things like GPS. There is so much stuff that is uselessly vague (or implies that it overrides manufacturer's guidelines) that a lawyer would have a field day with it.

Luckily, there isn't much data on what happens in bodged DIY IAPs

http://www.aaiu.ie/AAIUviewitem.asp?id=4719&lang=ENG&loc=1280

Summary;

G-HAUG departed Belfast International - Aldergrove Airport on 12 December at 18.03 hrs, to return to its home base at Ballyedmond, Co. Down, Northern Ireland. This would normally be a flight of some 20 minutes duration. The approach to the home base was executed using a locally produced GPS-based approach procedure. Having commenced its descent, in preparation for landing at Ballyedmond, the helicopter struck the north face of the Carlingford Mountains at 960 feet above sea level, approximately 2 miles SE of the village of Omeath, Co. Louth, at 18.16 hrs. All three occupants suffered fatal injuries.

Who wants lots of that type of data?

Regards,

DFC

DFC,
that accident does not show the error of using a DIY approach; it shows the error of not following a procedure correctly. Every year there are umpteen accidents where aircraft have diverged from published procedures that ARE approved.

For those who asked about helicopter let downs offshore; The procedure is officially approved and published by Aerad. All operators around the N Sea use the same basic procedure, generally known as an ARA (airborne radar approach). It begins with the premise that MSA is 1500 ft, for the reasons given, but once the crew has established that there are no obstacles in the intended let down area, other than their destination rig/platform/ship, the aircraft can be descended on a promulgated profile. Normally it utilises an NDB on the destination along with GPS. Principly, though, it requires the wx radar, which is managed by the PNF to give a 'talk down' to the PF. MDH is 200 ft rad-alt and an offset is flown at 1.5 nm to ensure lateral separation. The descision point is at 0.75 nm.


DIY approaches are fraught with dangers and are not to be taken lightly.

"In all cases unless the person in question was in receipt of a radar service Im sure his airmanship would be called into question...and whilst he might not have broken any law would you (given the advice from the authorities) possibly consider his actions to be reckless or negligent given that such advice was for a completely different set of actions? Would you have considered that the commander had placed his aircraft in danger?"

So how would a court have seen our IMC / night letdowns to a 50' hover over the sea? Quite a few more dead folk had we not done it....... ;)

"that accident does not show the error of using a DIY approach; it shows the error of not following a procedure correctly. Every year there are umpteen accidents where aircraft have diverged from published procedures that ARE approved."

I totally agree - once you fail to follow any let-down procedure, home grown or not, you are in uncharted territory and "loss of terrain clearance" is what may follow, even if the MAP is carried out correctly.

I wonder what criteria a pilot would use to design a DIY approach? Many years ago I spent several weeks on a Instrument Approach Procedure Design Course. If only we'd realised you could just cuff it with a GPS and the back of a fag packet we wouldn't have had to learn about navaid accuracy, obstacle clearance sectors, acceptable climb and descent rates, weather minimas, missed approach segments etc etc... if only (it was one hell of a course!). Seriously... DIY is for bodgers!

There is a publication called TERPS. The FAA uses that, AFAIK.

It's easy enough to "design" a DIY IAP for an airfield in flat country.

Doing it among terrain may require a special survey; it's not enough to take the elevations off the local Ordnance Survey map.

I know of at least one "approved" approach (GPS-A PAN (http://204.108.4.16/d-tpp/0507/06968RA.PDF)) approach in mountainous country (MSA 9300ft) which was designed by an interested GA pilot because the home airfield didn't have an approach. They got the books out, designed and test flew the approach themselves, then got the FAA in to validate it. The FAA came in with their test plane and approved it, cost to the airport/pilots a big fat zero. So it can be done by rank amateurs, but I'd only fly it myself once the "experts" had validated.

No met observer needed on the ground either, what a strange thing to do.

TERPS is here:

http://av-info.faa.gov/terps/directives%20page.htm

(warning: 28MB PDF!)

and leaves me in awe of the design process.

Tim

Are you allowed to fly a DIY approach in the UK if you only have an FAA IR? Part 91 says you cannot so you would be doing something your certificate does not authorise.

Which bit of Part 91 says so?

Sec. 91.175

Takeoff and landing under IFR.

(a) Instrument approaches to civil airports.
Unless otherwise authorized by the Administrator, when an instrument letdown to a civil airport is necessary, each person operating an aircraft, except a military aircraft of the United States, shall use a standard instrument approach procedure prescribed for the airport in part 97 of this
chapter.

IMHO this clearly refers to the official instrument approaches provided - if one is provided, one is supposed to use it and not some home-brew one.

If there isn't one provided, and the airport is in Class G, what does one do?

A DIY IAP could be anything between

a) a synthetic ILS straight onto the runway (like a real ILS), and

b) a descent in IMC under own navigation, a number of miles away, followed by a visual approach

and I cannot see how one can define where the boundary lies between these extremes.

So what you suggest amounts to a ban on any descent in IMC (for the purpose of a landing - and let's face it, every flight is done for the purpose of a landing :O ) except via an official IAP.

A DIY IAP is rarely going to be a), not least because there could be somebody in the circuit. One would normally descend a few miles away and proceed visually. The sort of MDH which one gets on a non-precision IAP (say 600ft AGL) is generally suitable for flight in VMC.

IO540,

I accept regulations are open to interpretation but try as I can, there is no way I can interpret 91.175(a) in the same way you do :)

You do bring up some interesting questions about Class G. Class G is not some lawless zone where the regs don't apply, you just don't need a clearance to fly in class G, IFR rules still apply.

FAA certificate holders are required to immediately climb to MEA which is specified in 91.177 and 91.179. Thats going to be 1000ft above anything within 5 miles, and also teh hemispherical rules apply. Basically no lower than 2000MSL or 3000MSL depending on your course.

You ask when the approach starts. For an airport with no IAP I would say the approach starts when you leave the MEA. What are the requirements? In Class G you need to have VFR minima (91.169(c)(2) ).

VFR mimima in Class G are

<=1200 AGL

during day clear of cloud and 1 miles vis; night 3 miles vis and 500/1000/2000 (91.155).

>=1200 AGL

day 1 miles vis and 500/1000/2000
night 3 miles and 500/1000/2000

This says to me that pilots relying solely on their FAA certicate to fly IFR cannot descend below MEA in class G unless you are clear of clouds by 500/1000/2000 ft.



Sec. 91.177

Minimum altitudes for IFR operations.

(a) Operation of aircraft at minimum altitudes. Except when necessary for takeoff or landing, no person may operate an aircraft under IFR below

...
..
(ii) .... an altitude of 1,000 feet above the highest obstacle within a horizontal distance of 4 nautical miles from the course to be flown.






Sec. 91.179

IFR cruising altitude or flight level.

(b) In uncontrolled airspace. Except while in a holding pattern of 2 minutes or less or while turning, each person operating an aircraft under IFR in level cruising flight in uncontrolled airspace shall maintain an appropriate altitude as follows:
(1) When operating below 18,000 feet MSL and--
(i) On a magnetic course of zero degrees through 179 degrees, any odd thousand foot MSL altitude (such as 3,000, 5,000, or 7,000); or
(ii) On a magnetic course of 180 degrees through 359 degrees, any even thousand foot MSL altitude (such as 2,000, 4,000, or 6,000).






91.169(c)(2)

(2) If no instrument approach procedure has been published in part 97 of this chapter and no special instrument approach procedure has been issued by the Administrator to the operator, for the alternate airport, the ceiling and visibility minima are those allowing descent from the MEA, approach, and landing under basic VFR.



However I agree that you don't need any minima to depart in class G. However FAA certificate holders might be interested in ....Careless Reckless (http://www.ntsb.gov/O_n_O/docs/AVIATION/3935.PDF) (PDF)

So that's my interpretation. Over to you

I think you're missing something, slim_slag. Part 97 describes only approaches to airports in the US. By your interpretation, an N-reg aircraft could never fly an IAP outside the US.

You also misconstrue 91.169(c)(2). 91.169(c) sets out the requirement for filing an alternate airport. 91.169(c)(2) set out the conditions under which an airport without IAP may be used to meet those requirements.

That said, given the airspace structure differences, I don't think the FAA would be nearly as flexible in interpreting the minimum altitude rule in regard to IAPs in the US as the CAA have to be in the UK.

I would climb down slightly from my earlier position, and concur with bookworm.

Unless one can get a letter from the FAA allowing in an N-reg whatever the CAA allows in a G-reg (which is far from impossible, looking at some written FAA replies I've seen) it may be safer for an N-reg FAA PPL/IR pilot wishing to fly an unofficial IAP to also have a UK PPL with an IMC Rating.

However - what constitutes an "IAP"? One could argue that any descent below what in the UK is called "MSA" i.e. < 1000ft AGL except in mountainous terrain where it is 2000ft. (In fact I don't even know for sure if the 2000ft is just FAA, or ICAO, or CAA).

And one could argue that a 1000ft MDH is reasonable for a DIY IAP, anyway. Which makes all this moot. (Trevor Thom says, in Book 5, it is OK to do a DIY descent TO the MSA so it must be OK :O )

It's doubly moot since the sort of place where one would be doing a DIY IAP in the UK is unlikely to have an accurate means of determining the cloudbase anyway.

Are you allowed to fly a DIY approach in the UK if you only have an FAA IR? Part 91 says you cannot so you would be doing something your certificate does not authorise.

...and it has been pointed out in another place, that Part 91 does not apply outside the US.

Moreover, FAR Part 91 Subpart H (91.701 etc) - ... US Registered Aircraft outside of the USA ...

states

91.703 (a) (2) When within a foreign country, comply with the regs relating to flight... of aircraft there in force

So an N-reg in UK airspace is required to comply with UK regs, and the main Part 91 does not apply.

Bookworm,

Looks like you have another different interpretation of the regs. I find it hard to believe you could say that FAA regulations do not apply to an FAA certificate holder flying an FAA registered plane as soon as that plane leaves US airspace.

IO540.

In one breath you are telling me that I have to follow 91.703 (a) (2) when in the UK, the next breath you tell me part 91 does not apply in the UK. By your logic I can just surely ignore 91.703 (a) (2) when in the UK.

This can't be settled without reading the entire FAR book and working out the interaction of every clause in there with every other one, and probably never with 100% certainty.

However, if you turn to page 159 in the 2005 FAR/AIM, Subpart A - General, $91.1 Applicability (a)

it states ...........

"within the United States, including the waters within 3nm of the US coast."

This "USA only" qualification extends, as far as I can see, all the way to Subpart H - Foreign Aircraft etc (page 211 of FAR/AIM) where it says

91.703 (a) (2) ... when within a foreign country, comply with the regs relating to the flight ... there in force

and

91.703 (a) (3)

... comply with this part so far as it is not inconsistent with applicable regulations of the foreign country where the aircraft is operated or annex 2 of ICAO...

The bit which one could have fun debating is 91.703 (a) (3) where we could argue the extent to which a regulation prohibiting something in US airspace is applicable to a different country's airspace where the same thing is not prohibited (though not expressly permitted).

It is a fact that N-reg places can legally fly in UK airspace, and it is a fact that the UK has a different airspace structure. The privileges of the IMC Rating are what they are because of our airspace structure - one can see for example why the rest of Europe doesn't have an IMCR also.

Morning IO540,

I am guessing that 91.1 and 91.703 are in there to make sure Chicago Convention stuff are put in the FARs. My understanding of these ICAO regs are that if you are flying in (for example) UK airspace in a US plane with a US pilot certificate, and there is any discrepancy/uncertainty in the regs, the more restrictive will apply.

So, its my interpretation (oh no, not another one!) that the FARS expressly prohibit an instrument letdown to a civil airport unless there is an approved IAP. The UK don't appear to have that restriction. Therefore if you are depending on an FAA certificate, the more restrictive reg applies, and you cannot do an instrument letdown in UK airspace if no CAA approved IAP exists.

If somebody else inteprets differently and wants to do so then that's up to them, but I would not expect the FAA to turn a blind eye if you hurt somebody and survived. So I would not do it without an IMCR, and even then my personal risk/reward calculation would prohibit it for me.

Bookworm,

I quoted 91.169(c)(2) to demonstrate that Class G is not a 'lawless zone' and regulations apply to IFR flight within that airspace and when letting down to an airport within.

cheers

slim_slag

Fair enough, we can leave the FAR v. ICAO v. CAA bit like that for now.

It still means that (UK, Class G) one can descend to the IFR MSA (1000ft above highest obstacle within 5nm I think; the FARs say something slightly different for the MOCA, IIRC, but 5nm is good enough) and provided one is then VMC one can continue with the approach visually.

One can even do a straight-in approach that way, not wisely but legally.

Which amounts to a DIY IAP with an MDH of 1000ft. That's good enough for most requirements.

Do that in say Wales and if your nav is less than 100% you will still get killed.

Why would this be illegal in the USA? It wouldn't be because you can legally fly AT the MOCA (if that's the level in your IFR clearance) and if you are visual then, you can elect to do a visual approach. So the argument is moot.

To re-iterate, there is no practical difference I can see between

a) Flying at MOCA (or MSA if UK/Europe) plus say 10000ft, and then descending to the MOCA 5nm away from the airfield, and if one is visual, doing a visual approach, and

b) Flying AT the MOCA all along and if visual doing a visual approach.

If there isn't one (an approach procedure) provided, and the airport is in Class G, what does one do?

Check the weather before departure to ensure VMC, or if airborne... divert. Not rocket science is it?

In the UK IAP design is against PANS-OPS criteria I believe. And yes it is complex - I seen and worked with the design software, and its pretty interesting - all about surfaces and stuff.