Stupid IFR questions.

[AdamFrisch]

Hi, as you'll soon painfully realize, I'm pretty clueless as to IFR procedures and stuff. I've had a bout 5 hrs of instrument training back in the days when it was mandatory for the old PPL, but it's the procedures I'd like to know more about. So here goes - a theoretical real example:

Let's say I want to fly from Lydd (that has a localizer/ILS) to Elstree (that hasn't), a pretty low level journey. The weather is terrible and I'll be in hard IMC all the way. The cloud base at Elstree is around 400ft.

Now, how is this done in real life?

Do I file a flight plan and ATC clear my via low level airways (above Transition Level) for a direct route crossing over London? Do I always have to file a flight plan for IFR? Or am I simply flying along in the clouds at my own chosen height pretty much as if I was in VFR except I can't see the ground, staying in G airpace? If so, how do I separate myself from another IR aircraft doing the same?

As I come to Elstree - can I land on it even though it has no ILS or NDB? Is there like a Minimum Decision Height for airports with no navaids or ILS's? If not, can I do an ILS approach down to where I'm in sight of the ground at a close by airport (Northolt, for instance), and then fly low level over to Elstree? Or am I pretty much only able to use airports with an ILS? Is the GPS legal to do approaches to minimas on?

Toldja, lots of silly questions. But these things keep me up at night.:}

[Nashers]

file a flight plan as its safer for someone to know what your up to.

you wont get a crossing over london unless your in a milti engine aircraft due to the glide clear problem, if you have an engine failure in an SEP.

if your flying the route class G then you dont have to file a flight plan. best thing to do is speak to any LARS service like manston, shoutend and Farnbrough on your route who will inform you of any other traffic.

i dont know if elstree has any nav aids on site, however if your realy in a pickle, you can do a possition fix and navigate by VORs like BKK i believe. if your above the feild with no nav aids and cant see it when your at you MSA, time to divert to southend and land there.

the whole point of an ILS is becasue the pilot knows that as long as they are on it, they are safe from hitting any buildings etc in that funnel to the ground. you cant do an ILS at one airport then fly low level to another one as you will prob fly into the side of a hill or something.

i dont understand your thought process about an MDH at an airport without nav aids. if you are flying into an airport without navaids and are in the white stuff, how would you even know you above it to start an approach with your MDH in mind??

[mm_flynn]

Do I file a flight planYou have two choices. 1 - low level outside the airway system (and no gurantee of CAS access) in which case you don't prefile a flight plan, but if you blag access to CAS (which won't be the TMA) you will have effectively had a flight plan created for you when you get the 'Cleared to Enter' call, 2 - 'A Eurcontrol Route' that is a route submitted into the IFR system and compliant with the route structure. In this particular case something like

-EGMD N0123F090 DET N57 LAM EGTR0041



I simply flying along in the clouds at my own chosen height pretty much as if I was in VFR except I can't see the ground, staying in G airpace? If so, how do I separate myself from another IR aircraft doing the same?
IFR OCAS below the transition level is basically just 1000 ft above the ground within 5 miles. With regard to separation you can either use a radar service (such as Farnborough) or Big Sky (in the UK no civil aircraft has yet hit another in IMC)

can I land on it even though it has no ILS or NDB? Is there like a Minimum Decision Height for airports with no navaids or ILS's?
This is a little tricky. The rule is drafted so that you can only decend below 1000 ft in IMC if you are visual with the ground or approaching to land. Oddly it is not a requirement (in the UK) that you are using an approach. So it is not illegal (except to the extent it might be reckless) to land without following an approach in IMC

If not, can I do an ILS approach down to where I'm in sight of the ground at a close by airport (Northolt, for instance), and then fly low level over to Elstree?

Yes, but at 400 ft ceiling you will be hard pressed to get from Northolt to Elstree while remaining out of cloud and 500 ft above any person or structure and glide clear and built up areas ....

Is the GPS legal to do approaches to minimas on?of course it is - GPS approaches have minimas just like all other approaches. You might have meant to ask, can I just make up an approach and use my GPS to navigate - and this is just as legal (or reckless) as making up any other approach.

[IO540]

mm_flynn's answers are good.

This is not a stupid question at all.

It is a very good illustration of how the utility value of flying goes in the bin the moment the cloudbase goes below about 1000ft AGL. Most "GA" airfields have no instrument approaches and only an ILS is going to get you below 400ft anyway.

A departure in these conditions is easy, for an instrument-competent pilot. It is purely a risk management thingy - if you have climbed into IMC and then get an engine failure, you may have only a few hundred feet in which you will be visual, to find a field.

Enroute is also no problem at all. Practically nobody else will be flying, so just drill along at 2300ft or whatever, below the LTMA. If you can get a radar service (Farnborough) so much the better. Nav would be GPS, obviously.

It is landing that's the fun bit. Only a brave pilot would do a DIY cloudbreak in a 400ft cloudbase. Such an approach would require very careful preplanning with the 1:25k O/Survey map and IMHO would be daft to fly without testing it first in VMC, and would require a general lack of obstructions in the vicinity. I would not do it down to 400ft, except if a descent is possible over the sea and the runway starts more or less on the beach. A 600ft decision height is much better. The procedure design is in any case critical and various things need to be done exactly right. For starters, you will be creating user waypoints in the GPS and if somebody else flying with that GPS changes them ..... so a VOR/DME backup on the waypoints is IMHO essential. This is not for amateurs. And it is illegal in an N-reg plane (reference: FAR 91.175) worldwide (IMHO).

Statistically, OVC004 is rare but OVC008 is much more common (UK warm front weather). A GPS approach would work fine for OVC008, but various stupid issues prevent them being adopted at places like Elstree.

[AdamFrisch]

i dont understand your thought process about an MDH at an airport without nav aids. if you are flying into an airport without navaids and are in the white stuff, how would you even know you above it to start an approach with your MDH in mind??

Thanks. Well, I was thinking of a GPS approach here. Fly in the soup, descent to MDH (if such exists for no navaid airport) and when you reach it, see the ground? If not, go somewhere else. But if I understand mm_flynn, that would have to be 1000ft.

As for IFR on OCAS. We all know calling up a radar service is optional, and even if I do so, this doesn't mean the other one chap has bothered to. So if I'm in clouds IFR in G airspace, how to avoid hitting someone else doing exactly the same?

Thanks IO540. The 400ft was just hypothetical. Why wouldn't a 800ft cloud base make an Elstree approach legal? Depending if I'm over built up areas, i could descend to 500ft VFR, no?

Just to recap - so I could take off in the soup from Lydd, no flight plan, drill on in the soup in G airpace on my GPS. Fly around London City TMA like you do on any VFR flight and then pop down to 1000ft when my GPS says I'm near Elstree and have a look if I see the field? This is fully legal, I don't need to speak or file with anyone?

[IO540]

how to avoid hitting someone else doing exactly the same?

The sky is big and planes are small :)

Why wouldn't a 800ft cloud base make an Elstree approach legal? Depending if I'm over built up areas, i could descend to 500ft VFR, no?

800ft would make it a lot safer.

In a G-reg, it is not illegal to descend below MSA or even below 500ft if you are landing.

so I could take off in the soup from Lydd, no flight plan, drill on in the soup in G airpace on my GPS.

OK.

Fly around London City TMA like you do on any VFR flight

Might be dodgy due to the glide clear rule - various opinions on the LCY area for single engine planes have appeared.

and then pop down to 1000ft when my GPS says I'm near Elstree and have a look if I see the field? This is fully legal, I don't need to speak or file with anyone?

It's totally legal.

Just make sure you are 1000ft above whatever obstacles are where you are popping down to have a look around :) :)

[mm_flynn]

We all know calling up a radar service is optional, and even if I do so, this doesn't mean the other one chap has bothered to. So if I'm in clouds IFR in G airspace, how to avoid hitting someone else doing exactly the same?luck? It took me years to get used to the fact that in many areas it is just big sky that provides the separation (I learned in the US East coast where all IFR is done in CAS - even if it is E - and being IFR without a flight plan is either illegal in itself or reckless if it is in class G). However, the fact is it seems to work (not withstanding the fact that Pace nearly wrapped a glider around his twin :eek:)

Just to provide some context to IOs 800 vs 400 comment. At most UK airports 800 ft AGL will be above any obstructions within miles, 400 ft AGL can be in the high tension lines a mile or so before the runway. So the risk (and hence the view of reckless) is quite a bit lower if you break off the approach at 800 ft without seeing the ground rather than 400 ft.


Just to recap - so I could take off in the soup from Lydd, no flight plan, drill on in the soup in G airpace on my GPS. Fly around London City TMA like you do on any VFR flight and then pop down to 1000ft when my GPS says I'm near Elstree and have a look if I see the field? This is fully legal, I don't need to speak or file with anyone?Yes

[AdamFrisch]

This is very interesting, because it makes a great case for the proposed Enroute IR. For what I gather from what you told me, for non-navaid airports and even full on ILS equipped ones, your MDH is going to be pretty much within the VFR limits. Why would I need a full IR when I can't get any lower legally than a VFR pilot anyway - it's not like my spam cam has Cat IIIc capabilities? Or worded differently - an Enroute IR would be just as useful as a full IR for 99% of the trips you do.

[ab33t]

You can file and fly in the TMA with single engine , just be prepared to have a load of altitude to get rid of . They will drop you out right above EGTR unless you request an early descent , then they will route you back out towards BPK or LAM.
Clarification on the GPS , it has to be an approved procedure and GPS cannot be a portable unit , it must be certified for approaches . At LYDD for example the MDA is 430 on the ILS and I think its 460 or something like that on the GPS21 Y . That means should you need to return for some reason you will not have the MDA before breaking clear of cloud .

LAM works quite well into EGTR and I would not go below +- 800ft as said before , there are a few tall buildings at 2 miles for 26

[IO540]

an Enroute IR would be just as useful as a full IR for 99% of the trips you do.

Possibly.

What "we" don't know is the details. I have heard on reasonably good authority that the EIR would require a Z flight plan i.e. a VFR departure and a VFR arrival. In such a case one could not legally fly a DIY (or any other) instrument approach.

There is no doubt that being able to fly enroute IFR (i.e. with a whole-route IFR clearance, with ATC working for you) would be very beneficial.

[mm_flynn]

...For what I gather from what you told me, for non-navaid airports and even full on ILS equipped ones, your MDH is going to be pretty much within the VFR limits. Why would I need a full IR when I can't get any lower legally than a VFR pilot anyway...Huhh??? You got the wrong end of the stick somewhere.
Yes broadly it is a good idea to be able to break out into low VFR for an airport without a published approach, but for an airport with an approach an IR rated pilot can legally go down to system minimums (with two crew or a suitable autopilot that would be 200ft and 550 RVR - aka Sh!t weather)

In the UK it is only broadly a good idea to use 1000 ft as your MDA without an approach - some places this is a bit shaky and others you could use 500-600 ft.

[AdamFrisch]

mm_flynn,
What I meant was that most of the MDA's for small aircraft, single crew, no fancy stuff seem to be in the 400-500ft region, and certainly higher for non precision approaches, even at big airports. This is awfully close to very marginal VFR, no?

Or put another way - how often would one encounter an approach without seeing the ground that could be done below 500ft, single crew, spam can?

[IO540]

Depends on the weather, obviously :)

Mind you, there are pilots who fly "VFR" in OVC004; mostly below the cloud...

If you are going to be doing things properly, OVC002-004 is purely ILS weather. OVC005-OVC010 is nonprecision approach (e.g. VOR/DME) weather, and OVC010+ is VFR weather if your navigation is spot on (i.e. with GPS).

Of course, the whole concept of "MSA" is down the drain if your navigation is imperfect ;)

Proper IFR (ILS down to 200ft) is not hard if you have a good plane, a good autopilot, and good tech knowledge of procedures etc.

[mm_flynn]

Adam,

400-500 ft MDAs ARE for non precision approaches, which intrinsically have no fancy stuff. It is very rare to have MDAs higher than this - and where they exist it is typically due to some quite nasty terrain - look at BGBW.

The key difference between operating in marginal VFR (and a 500 ft cloud base is pretty marginal) and an IFR approach is - When you are at 500ft and clear of cloud (i.e. MVFR) you know you are clear of the ground because you can see it. When you are approaching down to 500 ft, you know you are clear because you have set your altimeter correctly, you have navigated precisely along a surveyed route, or you have navigated along a route you have made up having carefully inspected a topo map to ensure you are clear about where any cables, antennas, buildings, hills, etc are.

The whole reason we have non-precision approaches is to get safely into very MVFR type conditions to visually manoeuvre to the field and land.

[AdamFrisch]

Thanks.

I've done 600ft cloud base quite recently, but thankfully the cowling inspection lid popped open and I had to return quite hastily. I would have returned anyway - 600ft is not that much fun. I had info it would clear up towards London, but I'm glad I didn't press on to find out.

I fancy an IR now to make my flying better and more useful professionally. But since I'd get most use of airports close to London, i.e. Denham, Esltree, Damyns Hall etc, it's a little annoying that after all the efforts of getting an IR, you still will end up not being able to fly in and use it on really bad days. Meaning that you can't rely on it as a means of transportation.

[IO540]

Yes, that's a good insight :ok:

If this was the USA, all these places would have GPS approaches, with MDHs of about 600ft, which is pretty good.

But it ain't going to happen here anytime soon, because the CAA mandates full ATC for any IAP and none of these airfields can afford the higher salaries. The only other way is to use a nearby IFR radar controller to do the approach scheduling but then his employer will bill the airfield, and again none of these places could afford it :)

If you want utility value, with a despatch rate in the 90% plus department, you need to base yourself at an ILS airport, and arrange your life so that you can mostly fly to ILS airports. And of course get yourself a decent plane (£100k plus) and some decent training. An IMCR is fine for hacking around the UK and you can get as good as you want - it's entirely up to you.

For European IFR you need an IR and believe me once you have an IR and have tasted flying into Europe, you will never want to go back. Flight into Europe is going to be into ILS airports (mainly) anyway, due to Customs requirements, so the problem largely takes care of itself.

BTW one cannot really fly around VFR enroute in OVC006. You have to be 500ft+ above man-made stuff (and that includes boats on the open sea) which leaves sod-all margin. People fairly regularly get killed doing that; they fly into hills and allsorts, and that is in the UK, not even in the Himalayas.

[englishal]

With many of the new aeroplanes out there, the technology is there to have an LPV approach to every single airfield in the uk....How many decades do you think this will take ;)

I'd use ~800-1000' for be comfortably safe on a home made approach. Hand flying an ILS to 200' is not difficult if you have a nice stable approach...Now couple the autopilot to an LPV, chop the throttle at 50' and it'll even autoland you ;)

[172driver]

This is fully legal, I don't need to speak or file with anyone?

AFAIK yes, ONLY in the UK and, IMHO, complete and utter madness

['I' in the sky]

172 Driver,

Well said, absolute lunacy !

[IO540]

It seems lunacy but the evidential support for the "lunacy" is exceedingly thin. So thin in fact that nobody can find it :)

The UK has not had a civilian mid-air in IMC since at least WW2.

[kenparry]

The UK has not had a civilian mid-air in IMC since at least WW2.

You may well be right - but it does not mean it cannot happen. Charging around IMC without some reliable means of separation is strictly for the birds, IMHO.

[IO540]

How would you propose to achieve guaranteed separation in IMC?

[Islander2]

You may well be right - but it does not mean it cannot happen. Charging around IMC without some reliable means of separation is strictly for the birds, IMHO.Why do you feel it is any more 'strictly for the birds' than is charging around in VMC without some reliable means of separation ... given that see and avoid as a means of separation has been demonstrated time and again to be unreliable?

[kenparry]

How would you propose to achieve guaranteed separation in IMC?

ATC radar fills the bill. What used to be called "Radar control" and now rejoices in the name of "Deconfliction Service".

[Islander2]

Quote:
How would you propose to achieve guaranteed separation in IMC?
ATC radar fills the bill. What used to be called "Radar control" and now rejoices in the name of "Deconfliction Service".
Well, that's another misconception then! Firstly because large areas of low level OCAS in the UK are not served by any kind of radar service, especially at weekends, and secondly because primary radar alone will not guarantee separation from some other types of aircraft (gliders, for example).

Actually, it's several more misconceptions, because 'Radar Control' cannot be available OCAS, by definition, and it is conceptually quite different from the Radar Advisory Service that has been renamed Deconfliction Service.
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[IO540]

Radar doesn't guarantee any separation.

It doesn't return altitude (that comes from a transponder; secondary radar) so

- if you are in CAS whose base doesn't reach the ground, ATC must assume that a primary-only blip is below CAS, but occassionally it isn't because the plane is busting CAS

- if you in CAS whose base does reach the ground, that is slightly better because ATC can then assume he is busting, but if he is low enough he will be seen intermittently at best, and watching ATC tape replays makes it obvious that some busts are totally missed (especially a small plastic plane)

- if you are OCAS, a lot of the time:

a) no radar service
b) radar service but a lot of conflicting traffic is not reported to you (no obligation to do so, evidently, because "controller workload" is always a defence)
c) radar service is meaningless against non-Mode C/S targets (no altitude info)

etc etc etc

"Total Safety" due to radar is an illusion. Radar just improves the odds.

If you REALLY want to improve your odds against a midair, do the following (in order of decreasing importance):

1) Fly well above 1000ft and preferably above 2000ft
2) Fly in IMC
3) Fly on bad VFR weather days (you also get much better radar service ;) ).