'Not above 500ft'

[Cyclically]

I fly a regular 'low level' survey in an SE helicopter in the UK which, due to its nature, takes us through many MATZs. We do not have any exemptions to fly below 500ft and so fly at 600ft AGL or above. I also make a point of stating on the radio that I am AT 600ft AGL (or sometimes just not above 1000ft). However the military have a habit (or perhaps a standard procedure, I’m not sure) of routinely responding with a clearance/request of "not above 500ft (QFE)". I always refuse this clearance (quite often to the disbelief of the controller!) and repeat that I need to remain AT 600ft (or not below). My reasoning is as follows…

If we assume that the ground I am over is at the same elevation as the airfield datum then if I comply with this clearance I am AT BEST only going to be 500ft above the ground. This therefore means that I will potentially be less than 500ft from any "person, vehicle, vessel or structure" as they are always closer to me than the actual ground. (and of course if the ground is higher then the problem is worse, and vice versa)

Yeah, ok, we are only talking about a few feet in many cases - e.g. I could now find myself at 450ft from a building or less than 400ft from power lines) but how would it stand up if someone were to be taken to court over it? I’m sure it wouldn’t be difficult for a lawyer to convince a jury that if one were to accept this clearance then contravention of rule 5(3)(b) (The 500 feet rule) would be inevitable.

I quite often hear this clearance accepted by other transiting aircraft (normally helicopters) so am I just being too pedantic? I would be grateful to hear other people’s views on this subject.

Oh, and finally, just to add further frustration, after being given this clearance and subsequently requesting a greater height I am quite often told something to the effect of "600ft is approved – there’s no traffic to effect"!! So why did they request it in the first place? Again, if there is anyone who is familiar with military ATC I would be grateful to know if this is a standard military procedure.

When speaking to the military would I do better saying that I am at 600ft MSD?

[What Limits]

You may be as well to request a clearance to operate 'not above' 1000ft QFE then you will have the freedom to change height as required.

[SASless]

Errrr......would it not be 600 AGL without any reference to an altimeter setting?


QFE (ancient and out of date quaint practice that is... would only be used for the single small spot/area on the aerodrome) would not be useful for determining true height above ground outside that location.


It would seem a QNH reference ( altitude requested providing the legal clearance required by the 500 foot rule) would be much more useful.


I assume ground elevation figures on UK charts/maps use height above Sea Level....thus a QNH altimeter setting would apply vice QFE.


The most immediate question is "how does one get nicked for violating the 500 foot rule in the situation described by the original post?"

In light of the F-15 crash following ATC providing an improper altitude clearance and the pointed criticism of the controller by the RAF review board....would not this clearance be improper?

[[email protected]]

SASless - You should fly on QFE within a MATZ because its dimensions are based on the airfield datum and all circuit traffic is using QFE. Regardless of ATC instructions the pilot is responsible for terrain clearance (as with F15s) not ATC.

Not quite sure why so much of the world has a problem with the concept that an altimeter reads zero when you land (using QFE) it's not quaint just because you don't like it.

Cyclically - most MATZ circuit traffic is at 1000' QFE so a standard clearance would be not above 500' QFE to give adequate separation from circuit traffic.

If you want 600' or more then ask for it in your initial call - ATC are not clairvoyant. ie - request MATZ penetration at whatever height on QFE that you think will keep you 500' agl or more inside the MATZ.

If you cannot get the height you need due to circuit traffic then either wait, go around the MATZ or accept that you are flying in compliance with ATC instructions and are unlikely to be reported or prosecuted for illegal low flying.

[212man]

Not quite sure why so much of the world has a problem with the concept that an altimeter reads zero when you land (using QFE) it's not quaint just because you don't like it

They don't: they have a problem with the fact that a) sometimes you won't be able to set QFE if the airfield elevation is too high, thereby requiring a location specific change in SOPs, which is generally considered a bad practice, and b) it's one more altimeter setting to make, with one more potential for error. CFIT being the biggest cause of accidents, tends to focus the attention on limiting altimetry errors.

An instrument approach is just to a number, it doesn't matter what datum you are using. The actual landing is done visually, so it doesn't matter what the altimeter says as you land (in a helicopter it will read negatively, while IGE, anyway, until you lower the collective after touchdown due to Pressure Error ;))

Sorry for thread creep :ok:

[Hughes500]

Whats the problem with 500 ft ? The rule is 500 ft away not above. Therefore if you are at 500 ft on the qfe then you are not breaking any aviation rule with the exception of 1000ft rule if flying over a built up area. The CAA will not go for you - how do the muppets prove it ?

[A.Agincourt]

Cyclically: I believe that in the military 500' is either a traditional or standard height preferred for airfield crossing which provides adequate separation from the standard 1000' fixed wing circuit operations. I seem to remember a NATO reference to it somewhere. However, using QFE as the datum is fine and I do not see an issue with using it and all military traffic in the ATZ will be using it. I think that if your intended crossing point were outside the ATZ but within the MATZ you would be asked to set the QNH for the field.

I can see a problem when you are asked to set the QFE and given a height to fly not above when you are transiting within the MATZ and ATZ but clear of the airfield. As you say, the ground may come up to meet you and you might think you need a shovel to comply with the cleared level.

I seem to remember a reference to ATZ/QFE, MATZ/QNH otherwise Regional below transition. No doubt I will be corrected.:E

[somepitch]

i know the canadian air regs have an exemption for the 500' rule for the purposes of aerial inspection...do the JARs have a similar rule? if so would your low level survey fall under such an exemption?

[[email protected]]

212man - a) is not a problem in the UK and we fly around on RPS or QNH outside the MATZ just like everyone else so b) is irrelevant.

Maybe we should all use QNE for landing, that way you never have to reset your altimeter from 1013:)

The instrument approach on QFE is usually to the same numbers eg 150' for helicopters on a PAR or 200' for ILS so you don't have to do maths whilst flying - generally safer all round I would say.

As for pressure error - unless you are at the airfield datum your altimeter could be many feet positive or negative before you take-off - decision height or MDH are well outside ground effect anyway:)

[Shawn Coyle]

Not sure this thread won't slide into a QFE vs QNH debate (that must be on this forum somewhere...)
The problem with QFE is that almost noone else in the world uses it, and if you've been brought up with it, it's difficult to transition to using QNH for instrument approaches anywhere else in the world.
I remember reading a horror story in the mid-80's about an UK helicopter crew that didn't remember they had to use QNH when doing a radar approach at a German airfield with an elevation of 250' or so.
If memory serves me right, Oxford Air Training School doesn't use QFE at all, as their students come from all over the world, as just one example.

[MINself]

A very interesting thread, as I have also have been cleared to transit within MATZ not above 500' QFE (within the ATZ) over terrain that was higher than that of the aerodrome.

Afterwards this led made me think that maybe I should not have accepted this clearance as this meant I had to fly slightly below 500' agl although the aerodrome circuit was very busy with multiple FJs all at 1000' QFE. After consulting the Rules of the Air Regulations it does state that 500' in reference to Rule 5 RoA is measured in all directions and not just the vertical. This leads me to believe that unless your landing or taking off from a Goverment or licensed aerodromes in the UK then regardless of an ATC clearance you should not fly below 1000' of the height of the heighest obstacle within 600m of the aircraft when over a congested area or within 500' of persons, vehicles, vessels or structures which practically speaking means that you should not fly below 500' agl in the UK surely? unless your over a remote area.

Going back to the original question, IMHO no I don't think your being pedantic Cyclically, it shows an awareness that military controllers are not always familiar with the civilian regulations and a clearance offered by them does not necessarily have to be accepted as offered.

:ok:

[Presstransdown]

Cyclically

I consider this a very good post as I have had a similar clearance issued to me.

The various replies are interesting but some do not really answer your question.

I believe that the clearance is issued because of the use of QFE at Military airfields. Once the controller has it in his head that you are low level, then it is easier for him to keep you in that band for other traffic purposes.

You rightly say that rising ground away from the airfield will force you to break the 500ft rule. This is your responsibility alone and I am almost certain a military controller does not have the authority to absolve a civilian aircraft from the ANO rule unless you have a CAA exemption.

When entering a MATZ I make it clear my position and the hieght band I wish to operate. This may not give ATC an easy time but as a MATZ is not controlled airspace then he cannot get too prescriptive unless you approach the ATZ.

Having said that, I have found, in the main, military controllers to be of the very highest standard in the operation of the airfield and MATZ.
If they no that you are operating in a particular height band then they do not have to bother you or other aircraft with unnecessary traffic information and I think that may be one of the main reasons.

As far as whether QFE/QHN/QNE is the best setting to use then our company uses QNH only for IFR operations which I do not have a problem with and does offer certain advantages as pointed out in an earlier post.

However having recently operated IFR into a military airfield on QFE then that did not seem to be a great problem either providing on the go around you remember, once he has finished with you, to set QNH for terrain clearance and making sure you do not bust into other controlled airspace above.

Regards

P

[SASless]

Not quite sure why so much of the world has a problem with the concept that an altimeter reads zero when you land (using QFE) it's not quaint just because you don't like it.

Crab....I assume you meant why does the UK cling to this practice and the entire rest of the world does not. You are now part of Europe (by means of the railroad and political convention) thus perhaps ya'll might want to change your ways to conform....it really is a simpler method than that practiced now.

Does the altimeter really...really....read "0" when one alights upon the airfield?

[NickLappos]

Leave it to the nitpickers to search for a way to be at 500.00 feet and not, heaven forbid 498.33 feet above the ground.

The rule is "not less than 500", the rule is not "precisely 500".

Try flying at 600 feet away, and if you are wrong, you have margin.

The altimeter is not more accurate than about 70 feet in any case, considering its own imprecision and inaccuracy. So if you set your altimeter to station pressure, and read 500 feet, you could be as close as 430 feet. Deal with it.

[remote hook]

Despite the bugs in summer, and cold in winter, I'm sure glad I fly in Canada...

5ft, 50ft, 500ft, or 5000ft. Doesn't really matter much, pretty much do what we want, when we want. I think the rules in Europe would kill me.

RH

[Gaseous]

Watertight proof of infringement of 500 ft rule is not easy to come by. Prosecution is rare and successful prosecution rarer(Have there been any?). With normal instruments even the pilot cannot be sure of his exact height, let alone those on the ground. Fly sensibly (it sounds like you do) and dont worry about it. The path of least resistance is to accept the clearance and nail it at 500ft.
edit:
Even if you are at 300 ft AGL the complainer has to prove your track was within 400ft of his property, and what your height was, to get anywhere near a rule 5 infringement. (remember 3,4,5 triangles!)

[manfromuncle]

Hear hear, QFE is a waste of time if you ask me. As soon as you leave the airfield it's useless. Even when on the airfield it rarely reads correct. Much more sense to stick to the QNH all the time, like they do in the USA.

[HEDP]

I must admit that having flown both QFE and QNH airfield procedures I do prefer QFE.

Recently in the States I flew at three airfields in close proximity but with different elevations. I have to admit that having specified downwind, crosswind and baseleg altitudes as well as differing joining and departure altiiitudes all combined to ensure that I spent a good part of the circuit in busy traffic having to refer to a kneeboard to remind me of what height I should be at.

At least with QFE and a set of standard operating procedures you are eyes out at the important phases of approach and departure.

Oh and if 500 feet and below is unaceptable then perhaps it would be deemed safer for all to go round that piece of busy airspace..........

IMHO

[ShyTorque]

Shawn, the horror story was possibly the one about one of our squadron aircraft, RAF based in West Germany. If so, it was at Buckeburg and I know the pilot well. They very narrowly missed the trees, which were infesting the clouds.

[SASless]

Thirty seconds to jot down three airfield elevations on a Mars bar wrapper beats fiddling with knobs....and in most locations the elevation difference is a moot point. Now if you are in an area where there is a really huge elevation difference one would not be able to set a QFE setting anyway. The Mark I Eyeball can work wonders in determining height and in theory should trump the altimeter unless one is truly addicted to "numbers on the clock".

[check]

Unless I am misinformed QFE as from 1st September is no longer used for landing in the UK. Certainly on an instrument approach you are no longer given the QFE. On one of my last approaches in the UK I was given only QNH but was asked as it was early days , would I like the QFE.

I really don't have a problem with QNH as SASless says every one else uses it and like everything else you get used to it.

[Cyclically]

Thanks for everyone’s comments but perhaps I didn’t phrase the question(s) quite right.

Firstly let’s not turn this thread into an argument about pressure settings – that’s not the issue here (I’m sure there are many other threads where that can be done). Regardless of what pressure setting they use they are still asking you to be in the piece of airspace. i.e. 500ft AAL.

The point I am trying to make is that if I were to accept this 500ft AAL clearance then (from a lawyer’s point of view in the unlikely event of being prosecuted) even if the ground is at the same elevation as the airfield then whilst I am going to be 500ft away from the ground I am NOT going to be 500ft away from the top of buildings, pylons etc that I have to fly over. Ignoring instrument errors and pilot accuracy then, albeit pedantic, this is fact and so if one flies directly over anything on the ground then this would be contravening rule 5. Once you then introduce elevation differences the separation may be even less (or more but that’s not the issue here). We have to follow a specific route so I can’t avoid over flying every object on the ground and it also takes us right to the airfield boundaries so I can’t avoid the ATZs without loosing some of the survey due to ‘ATC restrictions’

With regard to being prosecuted, I appreciate unlikely but, I am considering the instance where one is heard to be accepting the clearance and therefore 'must' be breaking the rules rather than simply being reported for low flying by someone on the ground. Therefore I don’t accept the clearance as I don’t want to put my licence on the line. If we have to miss a bit of the survey out it’s not my problem – ‘I’m just the pilot!’

So my questions are therefore:

Do others agree that it is (potentially) a contravention of rule 5?
Do others happily accept this clearance?
Would I do better using the expression 600ft MSD? (and would the military accept this from a civvy aircraft)
As this seems to be a military expression can someone confirm the exact definition of Minimum Separation Distance? Does it mean ‘I am flying no closer than 600ft from any object and am not authorised to fly any closer’? If so then perhaps this would be a better statement when making the initial RT call.

[Hummingfrog]

Why hasn't your company got an exemption from the CAA to:-

"fly closer than 500ft to any person, vessel,vehicle or structure whilst flying over Great Britain for the purpose of photographic or geophysical survey".

The company I work for has this and has to follow various restrictions such as informing the police and recording the times of such low flying along with CANP iaw the UK Air Pilot ENR 1.10 - Flight planning.

You wouldn't then have to worry about what clearance a Mil Unit gives you.

HF

[Bravo73]

Why hasn't your company got an exemption from the CAA

Because I suspect that his company is carrying out surveys but without adhering to the various requirements if operating <500ft (ie helmets, TCAS, etc etc IIRC).

I could be wrong, of course...

[212man]

Crab, what maths are we talking about? You look at the approach plate, it says DA or MDA 430 ft (or whatever), and that's what you fly to. You don't add the DH/MDH to the airfield elevation to derive the DA/MDA.

[[email protected]]

212 - see HEDPs post. At cloudbreak on mimimas using QFE you know that a 150' DH on PAR means the runway centreline is 150' beneath you - with a QNH approach you have to subtract the elevation from the DH to know how much space below the cloud you have. It also means that METARS (based on airfield elevation) are directly relevant to your DH/MDH when looking for diversions.

Nick - I can't see how writing 3 pieces of information on a kneeboard is easier than adjusting one knob on an altimeter - I'm sure the Human Factors guys would have a field day with that one:)

Cyclically - don't bother asking for a MSD clearance, it doesn't exist. My question for you is - when outside the MATZ and operating on QNH are you using a rad alt to determine your height agl? If you are using altitude on QNH compared to ground elevations on the map then you are still very likely to go below 500' agl unless you add a healthy margin. My answer to your original question is still - look at the map and ask for a suitable clearance through the MATZ based on QFE that will keep you above your 500' agl. Alternatively give the unit a ring before you launch and tell them what you want to do to see if they can suggest a suitable clearance height.

[Jumbo Driver]

The point I am trying to make is that if I were to accept this 500ft AAL clearance then (from a lawyer’s point of view in the unlikely event of being prosecuted) even if the ground is at the same elevation as the airfield then whilst I am going to be 500ft away from the ground I am NOT going to be 500ft away from the top of buildings, pylons etc that I have to fly over. Ignoring instrument errors and pilot accuracy then, albeit pedantic, this is fact and so if one flies directly over anything on the ground then this would be contravening rule 5. Once you then introduce elevation differences the separation may be even less (or more but that’s not the issue here) ...
...
So my questions are therefore:
Do others agree that it is (potentially) a contravention of rule 5?
Do others happily accept this clearance?


As I see it, if you are not exempt from the 500ft Rule, then inevitably such a clearance as "not above 500ft" must put you in contravention of that Rule, unless the QFE datum on which it is based is on a significant plateau with respect to the area over which you are flying. I don't think it is pedantic to be concerned - put simply, in most circumstances this clearance would produce a prima facie breach of Rule 5(3)(b).

My answers to your two questions above are:

Yes, absolutely
I have not been put in this position (and I am not a rotary flyer) but if I were, the answer would be No, for the reasons given above.

Why do military controllers appear to be happy offering a clearance of "not above 500ft"? I had understood the military equivalent (in the relevant JSP) of the civilian low flying rule relates to 250ft rather than 500ft. Thus, such a clearance to the military would represent flying in a relatively "safe" band, i.e. between 1) above the absolute (JSP) minimum (unless specifically authorised) of 250ft and 2) below the civilian (Rules of the Air) minimum of 500ft. Now, I may have been misinformed, as the military rules contained in JSPs are not normally available to civilian pilots, (they certainly should be, but that is for another thread!) - but no doubt this belief can soon be confirmed - or corrected!

So, in summary, there could be several reasons for such a clearance being offered, viz

1) As you are on a survey, a military controller might assume you have an appropriate exemption from the relevant low flying rule,
2) They might be accustomed to basing their low-level clearances on a 250ft minimum rather than 500ft,
3) They might take the view that their responsibility within the clearance relates to other traffic in the area but the responsibility for terrain and obstacle clearance under VFR is yours.


Just a few thoughts ...


JD
:)

[Arm out the window]

Apologies if this doesn't apply in the UK, but the low flying regs in Australia have a clause saying something along the lines of, you're not illegally low flying if it's because of the inevitable stress of weather or compliance with an air traffic control clearance.
Our company have some low flying approvals but we don't do it willy nilly, only if it's required and doing things approved on the AOC. However, most of our flying around the local control zone is at 500 ft on QNH. That's usually the clearance, but I've been instructed sometimes to 'commence descent early to the pad' for example, and as long as I'm satisfied it's not a safety hazard, I'm happy to comply.
Do you guys not have a similar rule?

[Brain Potter]

crab,

I too am a UK military pilot that was brought up on QFE and I was undergoing flying training when we went over to QNH for a short time. I remember thinking that sense had prevailed when we reverted to QFE. However, after many years of flying around the world I am now strongly in favour of adoption of QNH for the following reasons:

1. Standardization. Just about everywhere else in the world uses QNH, including the majority of aviation in our own country. During the cold war we operated almost exclusively in UK mil environment, but nowadays deployed ops are our raison d'etre and virtually every fleet is undertaking QNH-based ops somewhere around the world. Interoperability is improved by adopting worldwide practices.

2. Training. As we have to adapt to QNH on ops - why even create a difficulty by having a different practice at home. Train as you fight?

3. Terrain awareness. Having QFE set whilst being vectored on an instrument approach removes a lot of terrain awareness from the cockpit. Yes, you know how high you are above the airfield, but its much harder to build awareness of separation from the surrounding terrain. In practice, this puts the onus for terrain avoidance totally on to the controller. The relationship between the approach minimum and height above the runway is quite easily read from the plate, but I suggest it is much harder to mentally calculate that 2000 feet QFE is safe separation from terrain which is higher than the airfield. I believe that use of QFE creates pilots who are culturally trained to place a great deal of trust in ATC not to fly them into a hill. Perhaps that's fine in RAF Lincolnshire, but what about in Kabul or even at Nellis? CFIT happens when aircraft fly into hillsides, not when they fly into runway thresholds. Which pressure setting is better near mountains?

4. Combined zone pressure settings. It is utter nonsense that aircraft land at Kinloss on the Lossiemouth QFE, whereas a zone QNH would be entirely reasonable.

I can see the logic of the arguments for QFE and historically, in the isolation of ops from our own airfields in UK/Germany, it worked. However, with smaller but more deployed forces I think it is time to wake-up and realise that we swimming against the tide. The transition will be painful for those fleets that don't deploy and for mil ATC - but an expeditionary force really should not be so parochial.

To address the original question. Most military aircraft can accept a 500 foot clearance as they are not subject to the ANO. The military controller is trained to apply military rules and may not have knowledge of regulations contained within the ANO.

[Gaseous]

inevitably such a clearance as "not above 500ft" must put you in contravention of that Rule

Surely it depends on the terrain. There are plenty of places where it is possible to fly at less than 500ftAGL without infringing rule 5. It is not inevitable rule 5 will be infringed by accepting such a clearance.

[Max_Chat]

As I understand it you don't need a clearance to transit a MATZ, therefor telling ATC that you intend to be at 600' agl should suffice as long as you are outside the ATZ, and they should be happy to accept what you are doing and deal with it.

Is the 500' rule negated if instructed, by ATC, to fly lower?

[Gaseous]

Is the 500' rule negated if instructed, by ATC, to fly lower?
No. The pilot must comply.
Your suggested method of crossing a matz wont make you popular if it is full of fast jets.:eek:

[HEDP]

Interestingly the Apache requires to operate on QNH for targetting but I still prefer to operate on QFE for landing and take-off.

One other thing that has been mentioned is the added requirement to change an altimeter pressure setting as a point of distraction; this is a slight red herring as you have to change from RPS to another setting anyway whether it be QFE or QNH.

As intimated earlier there is much more 'heads in' checking of altitudes to be flown under the QNH system as opposed to the ease of QFE practices. Again the terrain clearance issue is negated by procedure.

On deployed operations, most of the time, UK forces will be operating with UK military air traffic so issues are negated. That said it is not a problem to operate on QNH with other nationalities air traffic, just more heads in at the plates and detracting from lookout, IMHO.

The point about a common QFE at Kinloss/Lossie is another red herring as either way it would be a common QFE or QNH and height errors at the non manster airfield would still be evident for landing and take-off. The common QFE is to facilitate seperation between traffic on different frequencies in close proximity to each other. Incidentally the height errors are negligible as they are both near sea level.

It worries me greatly that anyone one would advocate disregarding either the MATZ in toto or indeed ATC request/direction within a MATZ. A height allocated by mutual consent is far better than to insist that you will do things at your height and air traffic 'be damned'. Military traffic can be of a vast variety of types and in the event that the airfield in question was dealing with an emergency for example, how would you as an aircraft captain feel if you were instructed to go around with an emergency because another aircraft insisted they were going to erode the seperation criteria required for a safe approach?

As for the below 500 feet rule, would the same question be valid for the Heathrow routes that require you to be not above 800 feet when over what I would assess to be a congested area? Does the same principle apply?

The same rules apply to a military helo that has not been authorised to low fly in any event, the question does not lie entirely in the civil arena. If not authorised to low fly would I comply with the instruction, sure I would if my risk assesment led me to believe that it was safer to comply with the air traffic instruction. This doesn't however answer the underlying question of whether it is legal or not, that I dont profess to know............

[Brain Potter]

HEDP,

I speak as a pilot of large jets, so please forgive my perspective as I very rarely operate VFR.

I don't understand what you mean by saying that there is more heads-in checking of plates when operating on QNH. The cleared altitudes are flown and the procedure followed until visual or at DA. The only extra work is to make a mental note of the airfield elevation at briefing stage - so that correct height for range judgement can be made once visual. In return for that one calculation you can have a warm feeling of knowing exactly how high you are above the terrain whilst IMC. Having experienced some appalling ATC around the world I am glad that they were not using QFE - which would have left me with a much more difficult task of trying to maintain awareness of "I'm that high above the airfield, so where does that put me relative to the mountain". Hence I am not quite so trusting of terrain clearance being left to correct procedural interpretation by a person on the ground. Perhaps your different view comes from VFR ops, where you are usually in sight of the ground?

In my experience UK deployed ops take place on QNH in accordance with host nation AIP. Even where we provide the ATC we usually share the airfield with the Americans and our own charter flights, both of which will operate on QNH. Traffic on different pressure settings always seems like a bad idea.

I disagree that Kinloss/Lossie is a red herring. There are many TMAs/CTZs in the world that serve multiple airports in close proximity and operate a common altimeter/QNH. The barometric pressure in the zone will be the same, and the precise pressure at each TDZ is not required and the differences in elevation are taken care of by having discrete DAs. There are no height errors as everybody is using altitude. Take the case of parallel runways - either you have a seperate QFE for each runway or operate on the same QNH with different DAs - each of which give the required OCH. Kinloss clutch procedures are based on Lossiemouth QFE, so an aircraft at DH at Kinloss is referencing the precise pressure at a TDZ several miles away! Yes, these procedures are workable, but the degree of reverse-engineering required highlights the anachronistic nature of QFE ops - why not just use QNH like the rest of the world?

The UK military operates several ATC procedures that are at odds with worldwide practice. Each can be justified on an individual basis, but net consequence is an unnecessary lack-of-commonality which, in my view, actually reduces the safety margins. As we concentrate our remaining forces on fewer bases the number of MATZ has been reduced, but traffic around those that remain has increased. Perhaps it's time to make a case for giving the bigger bases proper Class D CTZs? Transiting civilian traffic could not then ignore the airspace. In return the military could offer to standardize it's practices with ICAO/JAR to allow civilian traffic to use these zones more comfortably.

[HEDP]

Brian,

My 1st post was certainly refering to VFR operations where on three close airfields with differing elevations you had to be aware of different altitudes for crosswind, base leg and downwind as well as arrival and departure altitudes. This meant at least 8 different altitudes had to be at hand to fly in three different circuits. Most certainly more reference required to heads down info rather than eyes out in the circuit. A difference to IFR operations I admit.

It seems we have differing experience of deployed ops, for example an AT location may adhere to host nation procedures but Tac ATC in more austere locations work on QFE. A difference in requirement and situations guess.

You miss my point about the Kinloss/Lossie red herring. Whether QFE or QNH it will be the pressure reference of the master airfield therefore regardless of setting, it will be from an airfield some distance from the other. In this instance whatever is used there may be an innacurracy by virtue of the distance and therefore pressure differential whether common QFE or QNH. It was your comment that it utter nonsense to have a common QFE but your subsequent post counteracts that line by stating that a common QNH would be better. The same innacuracy would be present in either.

[purge98]

If you are worried about a foot or two then at what point in the aircraft the actual static pressure is detected by the altimeter is important.
Is it at the entrance to the static vent on the side of the fuselage or at the actual instrument?
You may find that you are even lower than you think you are if the instrument is 5 feet above the bottom of the fuselage and the pressure is detected at the instrument :eek:
I'll get my coat...

[Brain Potter]

As you say, different perspectives relative to IFR or VFR ops - although I suspect if you'd been taught to fly anywhere else but the UK then you would find QNH more natural. I see your point about the differing altitudes at 3 close airfields. However, remembering varying VFR pattern altitudes is another one of those airmanship-type things that the UK QFE system does not equip people for. Instead it engenders a "visual circuit = 1000 feet" (or whatever) pavlovian reponse. Which is all very well in the UK but, like it or not, the rest of the world aren't going to change and we are not doing ourselves any favours by training obscure practices into our youngsters - even if the underlying logic is sound.

You are not convincing me about clutch pressures.

A QFE is relevant to a specific runway - so that the altimeter reads zero at touchdown on that runway. A different runway, even at the same field, will have a different QFE unless the TDZE is identical. Some countries allow QFE inside the final approach fix - for example Paris De Gaulle offers 4 QFEs for the parallel runways.

Conversely, QNH is relevant to the whole airfield and the differences in runway elevations are accounted for by publishing different DAs and TDZEs for each runway. The pattern, approaches and missed approaches to the different runways are all flown on the same pressure setting and are thus coherent. A zone QNH is equally valid at all airfields in the zone, provided that barometric pressure does not change markedly over a few miles (not likely) and if it did the zone would adopt the lower QNH.

A zone QFE is not really a valid because, the altimeter only reads height above the TDZ of one particular runway within the zone. Aircraft flying to other fields/runways are not landing on QFE, they are landing on a pressure setting that gives neither height nor altitude. The special procedures that are published for Kinloss/Lossie are a case of bending conventional procedures and definitions to fit in with the Brit Mil QFE policy. I have not seen this practice anywhere else in the world.

Perhaps I should get back to plank forums? :)

[Presstransdown]

Cyclically

Yes you will be in contravention of rule 5
You do not accept the clearance.

You certainly do not need to accept the clearance in a MATZ

Do not let yourself be talked into illegaly flying. You are the Pilot in command, not under command.

As an aside we have a dispensation to rule 5 (and a few others) but I never use it unless I need to.

If a young person gets tipped off a horse and gets paralysed(Ive been to one or two) and daddy has a few horses and a lot of money then he will screw you to the wall in a civil court if he thinks you are responsible.

Your feet wont touch the ground.

The CAA or anybody else do not have to become involved at all.

You will have to hire a lawyer.

Regards

P

[[email protected]]

Max Chat - I think I see what you are getting at in that non-mil aircraft theoretically only have to recognise the standard 2nm/2000' ATZ part of a MATZ - however you will look v stupid flying inside the MATZ boundary without clearance if you have an airprox and anyway it's just bad airmanship to ignore airspace restrictions.

One of the reasons Mil controllers use the not above 500' QFE is that if we (the mil) are operating in accordance with ATC instructions, we are not illegally low flying - a similar dispensation does not appear to exist in the ANO for civ traffic.

Clutch QFEs are for deconflicting circuit and transit traffic, not for giving neat zeros on the altimeter for touchdown.

Strangely enough the military can manage to use QFE at mil airfields and then magically switch to use QNH at civvy airfields without disaster or confusion - most of us do it all the time so we are hardly unversed in the ways of the world outside. Many of us just prefer QFE to QNH as it does give standard heights for standard procedures and is one thing less to think about.

The NATO standard helicopter join used to be 500' QFE at right angles to the active runway so it wasn't just UK being difficult....people will be moaning about why the US still uses inches of mercury for pressure settings instead of millibars or hectopascals next.:)

[Bertie Thruster]

Presstransdown. I didn't know UK CIV SAR had a 5. 2. b. permission!

The CAA will not issue any UK HEMS operator with a written permission to not follow the "500ft rule".

[Presstransdown]

BT
It is written into the CAA AOC of SAR operator, for training and Ops
I do not know about HEMS. I Understand that HEMS has its own JARs section
although JAR OPS 3 does not apply to SAR.
regards
P

[Max_Chat]

My point is:

a. If a civilian helicopter needs to be low level to carry out his job and
b. needs to transit a MATZ and
c. is required by law to be above 500' agl

then what is he /she to do if a military controller should deny a clearance when in fact a clearance is not a legal requirement? An interesting conundrum.

I do get your point about blindly bumbling around in an active MATZ, very very stupid I agree. However, just to add another dimension, how do you square the circle of gliders without radios flying in an active MATZ, do they not operate without clearances?

[[email protected]]

Max, I know of plenty of MATZs where gliding sites operate close to the boundaries and some MATZs where gliding takes place when normal ops have ceased but I haven't seen non-resident (for want of a better term) gliders routinely penetrating MATZs without prior arrangement or normal clearance.

If they are doing it then they are barking and show very poor airmanship.

I think the real answer to cyclically's problem is the 6 Ps or is it 7?:)

[Max_Chat]

Yes and Yes (inside or outside a MATZ a very barking pastime indeed). Shame that MATZ's could not be CTZ's and given a status that would make sense (IMHO).