Trip report (Europe) UK to Spain

[peter-h]

This might be fun reading for you American pilots - you will appreciate your fantastic facilities and privileges even more http://www.peter2000.co.uk/aviation/granada/index.html

 

[gismo]

This might be fun reading for you American pilots - you will appreciate your fantastic facilities and privileges even more http://www.peter2000.co.uk/aviation/granada/index.html

Your report was very interesting. I knew that GA faces a lot more difficulty in Europe but I hadn't begun to consider all the issues presented in your planning section. Just having to deal with customs and "PPR" for fuel stops is way beyond my comprehension. I'm so glad that I do most of my flying in the US.

At the end of your report you requested feedback so here's mine WRT your fuel planning. Keep in mind that I really liked the report and just want to help make it as accurate as possible:

Every normal petrol burning engine delivers best efficiency (horsepower per fuel flow) at 25F LOP (lean of peak).

I don't believe that BFSC.min (efficiency peak) always occurs at 25 LOP (it varies with power and temp) but at 60-65% power that's pretty close and like you stated the curve is pretty flat in that vicinity.

In practice, the efficiency curve is relatively flat in that region and operating simply at peak EGT is nearly as good. At this point, called "stochiometric" combustion, there is an exact match between the number of hydrocarbon molecules being attached to oxygen molecules. Having too few hydrocarbon molecules (this is the LOP condition) simply means less power is generated. Having too many hydrocarbon molecules (this is the ROP - rich of peak - condition) results in unburnt fuel going out of the exhaust. Most modern car engines run at peak EGT all the time (except when cold, when the ECU enriches the mixture). However, aircraft engines of the type in the TB20 (Lycoming IO-540) cannot be run around peak EGT throughout their rated power range because their lightweight aircooled design prevents the resulting heat being dissipated at high power settings, or at low airflows (low aircraft speeds e.g. during climb).

The issue of operating at peak EGT combined with high power isn't just high CHT, the peak internal cylinder pressure rises dramatically as you enrichen from well LOP (that peak pressure is indirectly responsible for the higher CHTs) and the crank angle at which this peak pressure occurs moves towards TDC as well. At high power settings those two along with the associated higher temps combine to greatly increase the stresses inside the engine and this is the reason one should avoid the region around 25-50 ROP with greater and greater margins as the power is increased above approximately 60%.

There is a widespread belief in GA that operating LOP yields huge efficiency improvements but despite the most careful tests I have not been able to replicate this. Flying at constant IAS and constant prop RPM (i.e. keeping thrust, airframe drag and prop efficiency all constant) there is a roughly 10% fuel saving between 75F ROP and peak EGT, but under 1% fuel saving between peak EGT and any LOP setting. What does make a big difference to MPG is flying slower!

This I pretty much concur with. So many claims of big gains in fuel economy operating LOP include some caveat about "only losing 5 KT" which IMO seriously blurs the effect of LOP ops. When I compare the efficiency of 20 LOP vs 50 ROP (at a suitably low power level) at the same TAS I consistently see about a 5% improvement in economy running LOP. Of course this along with the other benfits of LOP is sufficient reason IMO to operate that way.

During climb, which is done with all 3 levers fully forward (unless using the constant-EGT method - see below) the above thermal limitations prevent operation at peak EGT and the fuel injection servo is factory adjusted to deliver an operating point of about 150F ROP. This results in approximately 30% of the fuel remaining unburnt but the combustion is a lot cooler - just like spraying water on a fire cools it. In fact one could just run the engine at peak EGT and spray water into the combustion chamber and it would be just as good and considerably cheaper, and this actually been done in some old designs.

It isn't the evaporatoration of the excess fuel that "cools the combustion" but rather the increased time from ignition to peak pressure plus slight decrease in produced power that generates the lower temps associated with excessively rich mixtures. And while water injection has been used to increase detonation margins at high power in some engines I'm pretty certain that it's effect is similar (slower combustion). In the case of full power overly rich mixtures, vaporization and heating of the 25% excess fuel absorbs less than 1/2% of the heat of combustion from the fuel that actually burns. Probably not even one degree of CHT's worth.

At cruise, below 75% of max rated power, the heat generated in the engine is lower and there is much more cooling, so one can run in the peak EGT region.

Peak EGT at 75% power is not conducive to engine longevity, 60-65% is a more reasonably power limit for peak EGT operation. Of course if the engine is derated for airframe considerations that would be 60-65% of the full (not derated) power output.

The highest power output (regardless of efficiency) is obtained around 100F ROP, for some reason.

The most accurate number for "best power is 80F ROP although 100F produces something like 99.5% or more.

This is a useful concept for high altitude flight in a non-turbocharged aircraft; at say FL200 the engine is breathing little air, the corresponding stochiometric fuel flow is equally low, and the power output is low. The aircraft goes slower and slower and, at the ultimate operating ceiling, all it can achieve is a speed just above the stall.

More nit-picking... The indicated airspeed at the absolute ceiling is the max range speed which is close to Vy (best rate) as this is the speed which requires the least amount of power for level flight. Vs (stall speed) is significanly lower and flight at just above Vs requires considerably more power than at Vy. But your point is valid, as you approach the absolute ceiling of an airplane the increased power provided by a richer mixture is generally more important than the slight loss of engine efficiency.

In this case, you want all power you can get and you aren't too bothered about fuel flow, so you set up 100F ROP.
Engine friction losses reduce at a lower RPM which is another factor one can play with when stretching things. Prop efficiency is more complex and I don't know anybody who understands it but I assume it does not change substantially between 2200-2575RPM which is the normal IO-540-C4D5D cruise range.

As you've guessed, there are no universal truths about prop efficiency vs RPM let alone the combined engine and prop efficiency vs RPM but the optimal RPM typically increases with TAS IIRC.

Finally, altitude affects overall efficiency because a particular aircraft flies with a higher AOA (angle of attack) in thinner air and this creates more drag. Different wing aerofoils are optimised for different cruise altitudes.

Actually, at the indicated airspeed that yields maximum no wind efficiency (typically close to but slightly higher than sea level Vy), altitude as absolutely no effect on airframe "efficiency" (i.e. distance/energy). IOW the power required to maintain altitude at that IAS increases exactly in proportion to the increase in TAS.

However, engine efficiency is not constant over its power output, is poor at the very low power outputs one gets at say FL200, and the result is that the best "MPG" is obtained around 7,000-10,000ft for most non-turbocharged GA aircraft types.

I don't think that's even remotely true. First of all, excluding extremely low power (less than necessary to sustain flight) engine power is very nearly proportional to fuel flow over the RPM range availble for cruise flight assuming the mixture is constant (it IS true that since the mixture must be overly rich at high power, this proportinality breaks down when the mixture must be made richer for safe operation of the engine). Second, from sea level to the absolute ceiling the range and MPG will be unaffected by altitude if flown at max range IAS. My claim does ignore the potential loss of efficiency during climb due to an excessively rich mixture although that can be eliminated by climbing LOP, and in any case the effect is small (.5gal/1000 ft) and on long flights the fuel wasted climbing ROP is a very small percent of the total consumed.


It is also true that most pilots operate at indicated speeds much in excess of best range and in that case a higher altitude will always be more efficient ignoring winds aloft and the aforementioned climb power issue.
If you want a better understanding of range optimization take a look at the website of the widely accepted guru on the subject:

www.db.erau.edu/research/cruise/piston.frame.html

 

[peter-h]

Hi lancefisher,

Thank you for the feedback - I will do corrections.

That bit about the latent heat of evaporation of liquid fuel - has this been calculated by somebody? If so then I have inadvertently repeated one of GA's OWTs!

Your input on efficiency versus altitude explains why I have repeatedly found that the penalty (in range, or MPG) paid for having to climb high (to get above wx) is much less significant than I would have expected.

However, I think I disagree with your assertion about engine power being proportional to fuel flow. It cannot be - if it were, the pumping+friction losses would have to be zero.

This graph comes out of the Lyco 540 engine manual

http://www.peter2000.co.uk/aviation/io-540-fig-3.16-fuel-consumption.jpg

and if one extrapolates the two axes to see the fuel flow that intercepts the zero-horsepower line, one finds this is very roughly (best economy curves) 5gph at 2575rpm, reducing to about 4gph at 2200rpm; the reduction is what one would expect if one assumed the pumping+friction losses were eating up 5gph at 2575rpm.

The other thing which I have not addressed is how the range improves as fuel is burnt off. This is another mystery to me. Jet operators are always talking about not loading more than "minimum" fuel because carrying un-needed fuel costs so much, but I repeatedly find the TB20 does exactly the same IAS at a given altitude no matter how how weight it is carrying. There might be a difference but it is really small; of the order of 1-2kt between the MTOW of 1400kg and say 1150kg with just me in it and half tanks. I cannot understand the mechanism for this; I suppose it could be that heavier loadings always involve the extra weight towards the rear, where it is beneficial in reducing the elevator AOA and thus elevator drag.

Finally, I remain unconvinced that my best-range speed is Vy. This assumes constant engine efficiency over power output, which (as stated above) cannot be the case. It should be with a glider (by definition ) and might be with an electric motor. I therefore think my best range is some 10-20kt above Vy (which is 95kt) but I am willing to do the measurements.

Peter

 

[gismo]

Hi lancefisher,

Thank you for the feedback - I will do corrections.

That bit about the latent heat of evaporation of liquid fuel - has this been calculated by somebody? If so then I have inadvertently repeated one of GA's OWTs!

The energy content on gasoline is approximately 120 times the latent heat of vaporization for gasoline. Couple that with the example of 25% additional fuel for "cooling" (80% combusted 20% not combusted) and you get a cooling effect that's 1/480 ths of the combustion energy. Technically you'd need to add in the energy used to raise the temp of the fuel to it's boiling point and a few other things but they are fairly inconsequential and cancel each other out to some extent. My information about the actual effects of a rich mixture on the combustion process is lifted primarily from George Braly's data (GAMI/APS).

Your input on efficiency versus altitude explains why I have repeatedly found that the penalty (in range, or MPG) paid for having to climb high (to get above wx) is much less significant than I would have expected.

However, I think I disagree with your assertion about engine power being proportional to fuel flow. It cannot be - if it were, the pumping+friction losses would have to be zero.

You are correct but the friction losses are relatively small compared to the power input. Most of the inefficiency is due to heat released in the exhaust and cylinders. The difference in friction losses at different power output levels is much smaller yet. The pumping loss is also relatively insignificant and for LOP cruising the difference at different power levels really tiny since the throttle is wide open for any power.

This graph comes out of the Lyco 540 engine manual

http://www.peter2000.co.uk/aviation/io-540-fig-3.16-fuel-consumption.jpg

and if one extrapolates the two axes to see the fuel flow that intercepts the zero-horsepower line, one finds this is very roughly (best economy curves) 5gph at 2575rpm, reducing to about 4gph at 2200rpm; the reduction is what one would expect if one assumed the pumping+friction losses were eating up 5gph at 2575rpm.

It appears to me that those graphs are based on using the throttle to set power and are not representative of true "best economy" operation.

Again, it is true that engine efficiency does vary with RPM and power output (but not with altitude). It's just that the deviation from a pure linear relationship between power and fuel flow is fairly small and when you combine this with prop efficiency the effect becomes mostly noise. The Byington article I posted a link to does presume that fuel flow is proportional to power so his data isn't perfect but it's pretty good.

The other thing which I have not addressed is how the range improves as fuel is burnt off. This is another mystery to me. Jet operators are always talking about not loading more than "minimum" fuel because carrying un-needed fuel costs so much, but I repeatedly find the TB20 does exactly the same IAS at a given altitude no matter how how weight it is carrying. There might be a difference but it is really small; of the order of 1-2kt between the MTOW of 1400kg and say 1150kg with just me in it and half tanks. I cannot understand the mechanism for this; I suppose it could be that heavier loadings always involve the extra weight towards the rear, where it is beneficial in reducing the elevator AOA and thus elevator drag.

This effect is pretty well explained in the Byington papers. IIRC you can expect about a 1% increase in power required for every 1% increase in weight. This is primarily if not solely due to the power required to generate the additional lift assuming the CG is unchanged. A CG that moves aft will also decrease the power required but the effect is pretty small. AFaIK, attempts have been made to measure that in a Bonanza but the results were inconclusive.

Finally, I remain unconvinced that my best-range speed is Vy. This assumes constant engine efficiency over power output, which (as stated above) cannot be the case. It should be with a glider (by definition ) and might be with an electric motor. I therefore think my best range is some 10-20kt above Vy (which is 95kt) but I am willing to do the measurements.

Best range is greater than Vy but not by 29%, I think it's more like 8% in my Baron but that's pretty close to your lower figure of 10%. And the range penalty for small increases above best range speed are fairly small too so I suspect that 120% of your Vy would be close enough and get you there a bit quicker. Of course, winds aloft have a huge effect on range (and best range CAS) so picking the altitude which maximizes range will likely have much more effect than an extra 10% speed.

 

[peter-h]

This effect is pretty well explained in the Byington papers. IIRC you can expect about a 1% increase in power required for every 1% increase in weight.

I am categorically not seeing anything like that at all.

The Byington(Bybington?) site is very interesting. I do have difficulty putting numbers in the equations in there though.

You must be right about the latent heat.

 

[flyingcheesehead]

This might be fun reading for you American pilots - you will appreciate your fantastic facilities and privileges even more http://www.peter2000.co.uk/aviation/granada/index.html

Peter,

Fascinating! Thanks for the excellent write-up.

We really do have it good here. No flight plans required, and I don't think we have ANY airports that are PPR in all situations (many are PPR for non-scheduled operations over 30 passenger seats, and some major ones like O'Hare or LaGuardia require slot reservations, but mostly neither is a problem for us little birds). We have lots of free weather and flight plan filing services available, and the XM Radio based weather service is relatively inexpensive and well worth it. Our avgas is the equivalent of about 0.75 Euros / liter.

Quick side note: Google rocks. I wasn't sure if I could combine unit and currency conversions, but sure enough - I googled "4 dollars/gallon in euros/liter" and got back "4 (U.S. dollars / US gallon) = 0.752358996 Euros / liter". Way cool, great time-saving tool.

I see you got your FAA commercial and instrument, so you probably already know how good we've got it.

A few questions: You mention "airway" flights, are you required to file an IFR flight plan along airways? (Most everything below FL180 here is GPS direct except for the busy northeast.) The transition altitude (where you go from feet to flight levels) is 18,000 feet (FL180) here, but IIRC it's much lower there and maybe different in each country?

The airways are different too. We have a very few, rare NDB "B" airways left, a few "Q" airways (GPS) starting to pop up, but for the most part we operate on Victor airways (between VOR's, 1200 AGL to FL180) and Jet airways (between high-altitude VOR's FL180 to FL650). I see that you have A, B, G, H, R, T, and Y airways in your flight plan! Are those in the different countries, or what are the differences between them?

BTW, Welcome aboard! We may call it Pilots of "America" but we welcome anyone to join us on this board, the best front porch of aviation on the Internet.

 

[peter-h]

A few questions: You mention "airway" flights, are you required to file an IFR flight plan along airways?

You need to file a "flight plan" for all flights in controlled airspace, for both VFR and IFR.

In practice this is usually done implicitly with a radio call, so in typical UK messing about if you want to cross a bit of Class D you just call them up and they grant you a transit (or they don't let you in and you go around it).

But if you want to fly in the "proper" Eurocontrol IFR airspace, it can be very difficult (virtually impossible in the UK) to get a VFR or a non-flight-planned IFR (e.g. Class G) flight elevated (what you call a pop-up IFR clearance) to the Eurocontrol airspace. So basically if you want to fly from the UK to say Austria, FL100-200 etc, you do have to file the IFR flight plan and it has to be validated by the Big Computer in Brussels as I described in the writeup. Developing a route which validates used to be an absolute pig at times, but the very new routing tools have changed all this.

(Most everything below FL180 here is GPS direct except for the busy northeast.) The transition altitude (where you go from feet to flight levels) is 18,000 feet (FL180) here, but IIRC it's much lower there and maybe different in each country?

Yes, the USA has a simple airspace, with E to 17999ft. It would be great to have that in Europe, but it would also mean that you would need an IFR clearance to enter IMC which would mean an IR, which historically has been very hard to get.

The Eurocontrol routes have an airway MEA typically FL070, higher due to terrain obviously in some places, but practically speaking it can be pretty messy to get a flight plan into Big Computer at FL070 (due to shortage of airways that low) and FL100 is a lot more productive. FL140+ is easier still and I normally file for FL160, and then ask for a "stop climb" once in VMC.

The airways are different too. We have a very few, rare NDB "B" airways left, a few "Q" airways (GPS) starting to pop up, but for the most part we operate on Victor airways (between VOR's, 1200 AGL to FL180) and Jet airways (between high-altitude VOR's FL180 to FL650). I see that you have A, B, G, H, R, T, and Y airways in your flight plan! Are those in the different countries, or what are the differences between them?

I have no idea what the letters mean You just print off the waypoints, stuff them into the GPS, and fly...

In general terms L means lower airways (below FL200) and U means upper airways (above FL200) which I won't be going into (ceiling FL200).

One gets a lot of DCTs here too and one always asks ATC for these, but often they are not allowed due to stuff like military/restricted airspace.

 

[john smith]

Yes, the USA has a simple airspace, with E to 17999ft. It would be great to have that in Europe, but it would also mean that you would need an IFR clearance to enter IMC which would mean an IR, which historically has been very hard to get.

I find this statement is confusing.
Are you saying that you can file and IFR flight plan without and IR [instrument rating] so long as you do not enter IMC [instrument meteorological conditions]?

Or do you mean you need an IR to enter FL180 and above?

 

[peter-h]

Are you saying that you can file and IFR flight plan without and IR [instrument rating] so long as you do not enter IMC [instrument meteorological conditions]?

In the UK you can do this, in Class G only I think, because a UK PPL holder can fly IFR so long as the actual conditions are VMC (in simple terms 3000m vis and clear of cloud).

It is however a pretty pointless privilege, because the filing of a flight plan doesn't actually give you anything (unless you crash and then they have some idea of where to look for you) and in Class G nobody really cares what you do anyway. The FP does not get sent to anybody apart from departure and destination so if you come to an ATC unit enroute which controls a piece of Class D, they will know nothing about you in advance.

I think the reason why UK PPLs are allowed to fly IFR in actual VMC is because in the UK all night flight is IFR, and this was the only way to make it work. It then creates some grey areas if a U.S. PPL wants to fly at night in the UK - he has an automatic night privilege, but the FARs require an IR for any IFR flight

I've got some notes on "real" IFR flight in Europe here

http://www.peter2000.co.uk/aviation/ifr-flying/index.html

which were originally written a few years ago following questions from a bunch of American pilots who wanted to fly to Europe.

 

[flyingcheesehead]

You need to file a "flight plan" for all flights in controlled airspace, for both VFR and IFR.

I would say "That's a pain!" but IIRC you have a lot more uncontrolled (G) airspace there than we do here, right? Here's it's mostly E above 700 or 1200 AGL.

In practice this is usually done implicitly with a radio call, so in typical UK messing about if you want to cross a bit of Class D you just call them up and they grant you a transit (or they don't let you in and you go around it).

Hmmm. So in this case you'd be in G-space, and you talk to the tower to try to get through the D-space and that's your "flight plan?" That's not so bad. In practice, that's pretty much how it works here only that's not what we call a flight plan.

But if you want to fly in the "proper" Eurocontrol IFR airspace, it can be very difficult (virtually impossible in the UK) to get a VFR or a non-flight-planned IFR (e.g. Class G) flight elevated (what you call a pop-up IFR clearance) to the Eurocontrol airspace.

How high up is the Eurocontrol airspace? Can you fly VFR up there?

You say something about class G IFR too - How does that work? If it's "uncontrolled" then how do you know you're not going to run into another plane in IMC? Here, all airway MEA's and probably all of the off-route obstacle clearance altitudes used for GPS-direct navigation are at least in class E controlled airspace. The only part of an IFR flight here that would be in class G is the first 700 feet after takeoff, or the last 700 feet on the approach.

Yes, the USA has a simple airspace, with E to 17999ft. It would be great to have that in Europe, but it would also mean that you would need an IFR clearance to enter IMC which would mean an IR, which historically has been very hard to get.

So you can go in IMC without a clearance?

We had a discussion about some of this on the Pilotcast forums a while back, and someone was talking about the requirements to get an IR over there. Disgustingly difficult - I think it's harder to get an IR as a Private pilot there than it is to get an ATP here, and the requirements were similar! That seems very counterproductive in terms of safety. I'm guessing that's also why you got your IR over here?

All this makes me want to just go hop in an airplane and go fly without talking to anyone. Well, I still have to talk to someone because I'm based at a class C airport, but I can "escape" pretty easily.

 

[peter-h]

How high up is the Eurocontrol airspace? Can you fly VFR up there?

I use that term for the controlled airspace in which the airways lie. It is usually Class A,B or C. Very occassionally it might be D or E.

If it is E then you can fly VFR there - this is very much applicable to France but the UK has almost no E.

You can fly VFR in C for example but whether you get transit depends on ATC.

You say something about class G IFR too - How does that work? If it's "uncontrolled" then how do you know you're not going to run into another plane in IMC?

The last mid-air in the UK in IMC was in 1942, so it works pretty well

So you can go in IMC without a clearance?

Under ICAO, nobody has the power to give you an IFR clearance (or any other clearance) in Class G. Isn't that how it works in the USA?

In Europe, there are countries where IFR is banned outside CAS i.e. in Class F/G. But in the UK you can do it, and no clearance or even radio contact is required. The VFR/IFR regime is pretty ambiguous, because you can fly IMC (IFR) all over the place, doing your own thing.

I read somewhere that U.S. pilots have been done for flying in IMC (and thus IFR) in Class G, but they got done not for not having a clearance but for not having filed an IFR flight plan.

We had a discussion about some of this on the Pilotcast forums a while back, and someone was talking about the requirements to get an IR over there. Disgustingly difficult - I think it's harder to get an IR as a Private pilot there than it is to get an ATP here, and the requirements were similar! That seems very counterproductive in terms of safety. I'm guessing that's also why you got your IR over here?

Yes, the U.S. ATP is probably easier than the Euro IR, certainly in terms of study. I guess the checkrides are to a similar standard between the JAA IR and the FAA IR.

I did the FAA IR (in the USA) for various reasons - the study volume, the flexibility of where you can do it, etc. There are advantages on the maintenance front; not so much on regular work but on add-ons (STCs etc) and modifications. It is also far cheaper to do the IR in the USA - even with today's exchange rates. How long the regulators here will allow it to continue, I don't know. There is a proposal out (see pages 159-161) to strip European residents of foreign license privileges in 2012 but few believe it can really happen because of the impact on the jet etc ops.

 

[flyingcheesehead]

I use that term for the controlled airspace in which the airways lie. It is usually Class A,B or C. Very occassionally it might be D or E.

Ah yes... Here, class A is from FL180 on up, none below that. We may ***** and moan about the Bravo around Chicago being unfriendly, but isn't the airspace around London class A? What altitudes are the different airspaces over there?

If it is E then you can fly VFR there - this is very much applicable to France but the UK has almost no E.

What does the UK have instead of E?

The last mid-air in the UK in IMC was in 1942, so it works pretty well

Well, when next to nobody flies, I guess it would.

Under ICAO, nobody has the power to give you an IFR clearance (or any other clearance) in Class G. Isn't that how it works in the USA?

Pretty much, but there is so little G here that you wouldn't dare - Plus, it's supposed to be 1 mile vis and clear of clouds in G. Is that different over there?

In Europe, there are countries where IFR is banned outside CAS i.e. in Class F/G. But in the UK you can do it, and no clearance or even radio contact is required. The VFR/IFR regime is pretty ambiguous, because you can fly IMC (IFR) all over the place, doing your own thing.

Yikes!

BTW, we have no F-space over here at all, so I don't even really know what it is. What's the difference between F and G? Where do you find F?

 

[John in England]

This might be fun reading for you American pilots - you will appreciate your fantastic facilities and privileges even more http://www.peter2000.co.uk/aviation/granada/index.html

Hi Peter,

Excellent report. When I was flying corporate (N-reg C340 & C421c), I used to fly to continental destinations regularly, especially Spain, namely Barajas (Madrid) & Malaga with others thrown in at the last minute to keep me on my toes!!, so reading your report brought back many memories.

well done.

regards

John

Comm; AMEL IR (US)

 

[peter-h]

Ah yes... Here, class A is from FL180 on up, none below that. We may ***** and moan about the Bravo around Chicago being unfriendly, but isn't the airspace around London class A? What altitudes are the different airspaces over there?

It varies all over the place. Where I live, Class A base is 2500ft.

What does the UK have instead of E?

G, I suppose There isn't the relatively regular airspace structure you have. It's basically G, with bits of D around airports (sometimes A) and big chunks of A for the airways.

Well, when next to nobody flies, I guess it would.

The UK has a pretty busy GA scene, but very few pilots fly in IMC, and I think this is true everywhere - even the USA?

Pretty much, but there is so little G here that you wouldn't dare - Plus, it's supposed to be 1 mile vis and clear of clouds in G. Is that different over there?

3000m vis and clear of cloud, though above 3000ft (I think) there are cloud spacing rules (which are basically pointless).

BTW, we have no F-space over here at all, so I don't even really know what it is. What's the difference between F and G? Where do you find F?

Very few places. I think F is advisory VFR routes - irrelevant. VFR flight, outside controlled airspace, can just go DCT.

Thank you John - you used to fly 421Cs across the Atlantic?

 

[sba55]

The UK has a pretty busy GA scene, but very few pilots fly in IMC, and I think this is true everywhere - even the USA?

Peter,

That's certainly not the case here. Not everybody has an IFR rating, but for those that do, flying IFR in IMC is routine. I'm surprised (or maybe not, going by what I've read here and what a good friend of mine who used to fly in the UK all the time has told me) this isn't true in the UK, too....

-Felix

 

[peter-h]

It is and it isn't.

Here in the UK, a lot (maybe 10-20% ?) of PPLs have the IMC Rating, which is basically an IR but UK-only, no Class A, 1800m min vis for t/o or landing. I used to have this until I got the full IR. In this case, one cannot file the big-boys IFR flight plans for high altitudes so you often fly at 2400ft, 3400ft, etc, just under the base of various chunks of Class A. And yes, in IMC.

But on a given day when it is say OVC010, very few people are flying anyway. Obviously, the near misses are never detected.... you can get a radar service but often you cannot; it depends on the workload.

Once you get the full IR (maybe 1-2% of UK PPLs have this) then you can file flight plans which are vertically limited essentially only by aircraft performance - just like in the USA and everywhere else. In this case, you get some data on cloud tops (that's another story) and file for a few thousand feet above that. Typically one files for FL150 etc, you climb to sunshine and sit there the whole route. Only hardened de-iced hacks fly for hours in IMC, because the airway levels (FL070+) place you into icing conditions more or less any time of the year, anywhere in Europe. And in this mode, you get an automatic radar service with separation.

So.... flying enroute in IMC is fine at low levels, typically done outside CAS, and also occassionally done by traffic flying illegal VFR (the ambiguity here between VFR and IFR in Class G makes the distinction meaningless, but not above 1999kg when you pay enroute charges if IFR) but you generally cannot do it at higher levels due to icing.

US airspace is clever because you have widespread Class E which makes it illegal to fly in IMC without an IFR clearance. This works because of your much more accessible IR so lots of people can fly in the system properly, and it works because airports etc do not get billed by the IFR control units for the radar service. Here they do get billed which makes it very hard for GA airfields without ATC to get GPS approaches - they could not afford the charges from the controlling unit. So the UK free-for-all Class G model works quite well - nobody wants to pay, so nobody charges, but nobody gets an assured radar service. France is quite close to the USA - Class E to FL110, Class D above, Class A FL200+, or so and subsidised ATC facilities like the USA.

 

[john smith]

The last mid-air in the UK in IMC was in 1942, so it works pretty well

Fighters or bombers? )

 

[sba55]

Peter:

Thanks for the insight!

-Felix

 

[peter-h]

The 1942 one was allegedly a military on civilian. There is allegedly no record of a civ on civ mid-air in the UK, ever.

The UK has about 20k GA aircraft and about 20k private pilots who kind-of fly (measured by how many renew their medicals). This is probably the biggest population in Europe, with Germany being similar I believe. France is lagging behind as #3 and the rest of Europe is well behind, with e.g. Greece having only about 200-300 aeroplanes total.

The UK is pretty busy on a nice day. Flying at say 2000ft in the south, there is a LOT of traffic. But most fly at/below 2000ft which is why I tend to fly as high as airspace allows, even if sometimes it puts me into IMC. Nearly all midairs (the UK gets on average one per year, all in VMC) have happened at 1000ft AGL or below.

I looked at getting the Avidyne 600 TCAS put in but at $10-15k it is an expensive way of achieving very little since much traffic is nontransponding (esp. the low level stuff) and the aeroplane would need to have all the existing antennae moved around, which makes it a huge job trim-removal job. So I never did it, but a good number of the higher end GA owners have got it.

Once out of the UK, you can fly thousands of miles without getting visual with another GA aeroplane.

 

[flyingcheesehead]

It varies all over the place. Where I live, Class A base is 2500ft.

Yikes! Are you near a large city, IE is the 2500 feet part of the base of an "inverted wedding cake"?

The UK has a pretty busy GA scene, but very few pilots fly in IMC, and I think this is true everywhere - even the USA?

I think Felix is correct - There's a lot of IMC flight that happens here. Roughly 1/3 of US pilots are instrument rated. We don't have an "IMC rating" it's either nothing or the full-on instrument rating which allows you to fly a turbo bugsmasher up as high as you can get it (provided other requirements like oxygen, DME, RVSM, high-altitude endorsement if needed, etc. are met).

3000m vis and clear of cloud, though above 3000ft (I think) there are cloud spacing rules (which are basically pointless).

Well, the point of cloud-spacing rules is to allow you to see and avoid another aircraft that may pop out of that cloud.

It also sounds like you can't go in the clouds in class G without an instrument rating, or is that the IMC rating you speak of below?

Here in the UK, a lot (maybe 10-20% ?) of PPLs have the IMC Rating, which is basically an IR but UK-only, no Class A, 1800m min vis for t/o or landing. I used to have this until I got the full IR. In this case, one cannot file the big-boys IFR flight plans for high altitudes so you often fly at 2400ft, 3400ft, etc, just under the base of various chunks of Class A.

Interesting. At least there's an intermediate step on your way to the full instrument rating.

And yes, in IMC.

Are you in contact with ATC at all? Do you file some different kind of flight plan? Do you have to stay on airways? Is there anything besides the big sky theory that keeps you from hitting another plane in IMC?

But on a given day when it is say OVC010, very few people are flying anyway. Obviously, the near misses are never detected.... you can get a radar service but often you cannot; it depends on the workload.

I'm beginning to understand why that plane I ferried to Maine before it crossed the pond to start its new life in Europe had an active traffic system installed!

So.... flying enroute in IMC is fine at low levels, typically done outside CAS, and also occassionally done by traffic flying illegal VFR (the ambiguity here between VFR and IFR in Class G makes the distinction meaningless, but not above 1999kg when you pay enroute charges if IFR) but you generally cannot do it at higher levels due to icing.

Another interesting thing. Here, we call the Great Lakes an "ice machine." I bet the ocean makes it a lot worse!

US airspace is clever because you have widespread Class E which makes it illegal to fly in IMC without an IFR clearance. This works because of your much more accessible IR so lots of people can fly in the system properly, and it works because airports etc do not get billed by the IFR control units for the radar service. Here they do get billed which makes it very hard for GA airfields without ATC to get GPS approaches - they could not afford the charges from the controlling unit. So the UK free-for-all Class G model works quite well - nobody wants to pay, so nobody charges, but nobody gets an assured radar service. France is quite close to the USA - Class E to FL110, Class D above, Class A FL200+, or so and subsidised ATC facilities like the USA.

Man, I hope some senators are listening to this.

 

[peter-h]

Yikes! Are you near a large city, IE is the 2500 feet part of the base of an "inverted wedding cake"?

Not a lot of 'wedding cakes' here. We tend to get Class D zones, reaching up to say 2500ft and above that is a large area of Class A. If I could post a section of the chart I would. It's not a regular cake structure like you tend to see in the USA.

It also sounds like you can't go in the clouds in class G without an instrument rating, or is that the IMC rating you speak of below?

The IMC Rating is same privileges as an IR except

- IFR privileges are valid UK airspace only
- no flight in Class A
- min 1800m hor. vis for t/o and landing

The IMCR has an additional benefit which is that the UK issued PPL requirement to be in sight of surface for all VFR flight, is removed, so you can fly VMC on top (still VFR). This is not limited to the UK and is dead handy for long VFR touring around Europe. All my early trips (on my website peter2000.co.uk) were VFR and all relied heavily on VMC on top. This works well outside the UK, in many places, because the UK is one of only a few countries with lots of low level Class A.

However, EASA is planning to kill it off c. 2012, which is really stupid. I hope the USA never joins the European "Union"

Interesting. At least there's an intermediate step on your way to the full instrument rating.

Yes, very much so. However, the European (JAA) IR gives zero credit for the IMCR training time. You still have to do the full 50/55hrs dual training (SE/ME). The FAA however recognises all previous foreign training and allows the credit. I think the majority of UK based FAA IR holders (like me) started off with the IMCR, built up experience, and then went to the USA to do the FAA IR, which is achievable in something like 20-30hrs if you are already fairly good. Of course the FAA IR is not achievable in the min 15hrs dual training requirement.

The funny thing is that if you have an FAA (or any other ICAO) IR, you can do the JAA IR with just 15hrs dual training requirement, not 50/55 anymore. (You still have to sit all the IR exams though; 7 for PPL/IR and 14 for CPL/IR).

So, perversely, an efficient route to the JAA IR is to get the IMCR, get good, get the FAA IR (which even with today's fuel price is still pretty cheap, if done in the USA), and then do the JAA IR. That is the only way to get credits all the way up. But there is NO way to avoid all the silly exams.

Are you in contact with ATC at all? Do you file some different kind of flight plan? Do you have to stay on airways? Is there anything besides the big sky theory that keeps you from hitting another plane in IMC?

ATC (radio) contact is optional in Class G.

You can file a flight plan, formally or on the radio, VFR or IFR as you wish. Even if you file a VFR FP you can go into cloud because the VFR -> IFR change is purely in your mind (if you are non-radio) or you advise ATC (if on a service of some sort).

The exception is if you have been granted a crossing of a piece of CAS (say Class D) in which case they will allow it as VFR or IFR and they kind of expect you to be one or the other because they apply different separation standards to the two.

There is a belief that if you declare yourself "IFR" you are more likely to get a service, especially a radar service. IMHO this is true. Same goes for pilots who route via IFR waypoints (VORs etc) rather than routing via little village names. But ATC people dispute that this happens. When VFR and going a long way I always route fully as if IFR, and in some countries (e.g. Greece) ATC expect you to fly the published airways! However since I got the IR I have flown abroad IFR only.

The big sky theory works very well

I'm beginning to understand why that plane I ferried to Maine before it crossed the pond to start its new life in Europe had an active traffic system installed!

Yes but these see maybe 50% of the low level traffic, which is the only time you are like to get hit.

It would be better to fit powerful gas lights. These kits are on the US market (STCd) and I looked into them, but ideally I would like to fit a light cluster on the RH wing too and that is a massive certification exercise.

Another interesting thing. Here, we call the Great Lakes an "ice machine." I bet the ocean makes it a lot worse!

I read that too. We get icing here also, plenty of it. I avoid it as I have only a TKS prop, so for me it is VMC enroute at all costs.

Man, I hope some senators are listening to this.

The USA, from what I read (I get the Flying and AOPA mags from the US) is facing a unique once in a lifetime opportunity to shaft its GA activity, and if they do they will never be able to go back.

Route charges by themselves don't seem a problem, if set at a low level, but they encourage illegal VFR (best done in de-iced types, obviously) and DIY instrument approaches because even if every airport had a GPS approach you won't be able to use it if you are "VFR"...

In Europe, a Seneca (without the 1999kg STC flight manual mod) would pay about $200 for a ~ 600nm flight from the UK to the bottom end of France. That is a lot of money; a significant fraction of the cost of the fuel. The incentive to fly illegally VFR, or just (legally) scud run VFR under the cloud, is pretty big. It also reduces the pool of IR holders because the IR is devalued.

And if the USA introduced the "user pays" principle, hell would break loose because how do you then schedule traffic onto a GPS approach at some non-towered airfield?

We also have landing fees which range from say $10 (fine) to $800 at say London Gatwick (EGKK). I pay $20 where I am based. Obviously "nobody" in GA flies to Gatwick, except as a joke to show your mates the logbook entry Unfortunately a lot of nice places (e.g. Prague LKPR) are now around $200 which is OK for a rare trip but not if you go often.

You people need to work hard at this. But you have an excellent AOPA. European AOPAs are in comparison toothless.

I have met Phil Boyer, at Athens in 2008. There were several presentations; a few by various stuffy European regulators about how GPS is not good enough by itself and they want to mandate INS (for GA, no kidding) or LORAN, for PRNAV, and then Phil B takes the stand, and without actually saying anything dramatic completely wipes the others off the floor, just talking about what the USA has had for years. Airports with GPS approaches but with NO TOWER (we Europeans cannot do that, surely everybody will be killed!!). I think the other speakers wished they could vapourise.

Things are happening here. GPS approaches have just started. In 10 years' time...?