How accurate is your Mode C?

[mad_jock]

There aren't likely to be any non-emergency, non- military heavily loaded heavies operating a climb profile in the UK outside controlled airspace

The only one that springs to mind would be Filton possibly but a turn after departure would take them quite quickly into Cardiff airspace.

[Roffa]

mm_flynn,

There aren't likely to be any non-emergency, non- military heavily loaded heavies operating a climb profile in the UK outside controlled airspace, however, his point is similar to points UK ATCOs have previously made about why cutting a couple hundred feet into the bottom of LHRs departure airspace is a problem (which is not because aircraft are often scrapping the bottom, but sometimes they are - plus the obvious issue of 'it is against the rules')

The only departure that these days is likely to be close to the bottom of CAS on departure from LHR (barring unusual circumstances) is the A343 or A346. Everything else goes up at a reasonable rate.

Around LHR it is 09L/R arrivals that are far more likely to be embarrassed by anyone marginally inside CAS as, out to the west where the CAS base is 2,500ft or 3,500ft, the LHR arrivals are routinely only 500ft above said base altitude.

[SNS3Guppy]

If you don't have it then don't be surprised if folk complain. I know one corporate operator who was warned off and threatened with further action for flying over 250kts.

I very much doubt he was flying an aircraft that had a minimum safe clean speed in excess of 250 knots. If he was warned for flying above that speed, it's because he had the capability of flying at a lesser speed, and elected not to do so.

[ShyTorque]

The UK regulations don't make that distinction. If you need to do it, you still need written permission, or you are still breaking the law.

[soaringhigh650]

you are still breaking the law.

Then I'd rather break the law than put my aircraft in danger.

[BackPacker]

If you need to do it, you still need written permission, or you are still breaking the law.

Well, it doesn't sound like a one-off problem. Wouldn't Mr. Boeing already have talked to the CAA and gotten written permission for the whole 747 fleet, pointing to the AFM, SOPs and such?

If so, the written permission is likely to be lurking in a bottom drawer somewhere.

[ShyTorque]

Then I'd rather break the law than put my aircraft in danger

In an emergency I would do too.

But from what has been written, that isn't the case here. It appears to be pre-planned and carried out on a not uncommon basis.

It's unprofessional to be ignorant of the laws of any country over which we fly, or choose to ignore the ones we don't like, especially if safety may be compromised.

By that I mean the safety of others. The 250 kt rule is one of those rules and needs to be complied with irrespective of how heavy the commercial burden to the company to disregard it.

[lucaberta]

I'm sorry but I fail to see the point in all of these messages about "breaking the law" on the 250kts below 10000' in the UK, when you, ShyTorque, said this a few messages ago:

SNS3Guppy, The reason I asked was because under UK aviation law, you need a written permission to go above 250 kts in Class G airspace. I don't think ATC can give ad hoc permission on the day; Class G doesn't "belong" to ATC.

I trust that SNS3Guppy and his/her 747 spend most of their time during their initial climb in IFR within CAS? Am I wrong?

Ciao, Luca

[mm_flynn]

Originally Posted by BackPacker

Well, it doesn't sound like a one-off problem. Wouldn't Mr. Boeing already have talked to the CAA and gotten written permission for the whole 747 fleet, pointing to the AFM, SOPs and such?

If so, the written permission is likely to be lurking in a bottom drawer somewhere.

As I said earlier, there can't be many (if any) UK airports that cater to fully loaded 747s that are not either in controlled airspace to the ground or have a very short link into controlled airspace. As such, this rule with regard to Guppy's comments would seem to be a non-issue in the UK. (military excepted, who clearly operate on occasion well above 250 knots down low)

Filton was mentioned, but is unlikely, with only 2.7kms of runway, to be handling a fully loaded 747 . Manston is the only civil airport I could think of with a long runway and no controlled airspace (and even this is about 1200 metres less than LHR in ASDA) and no direct connection to controlled airspace. So I guess if anyone ever planned to operate heavy 747s out of Manston they would need to get the permission.

[ShyTorque]

I trust that SNS3Guppy and his/her 747 spend most of their time during their initial climb in IFR within CAS? Am I wrong?

lucaberta, Yes, but my concern was this quote:

As a function of our IFR clearance, and our operations specifications issued to us by the government agency that oversees our operation...which includes operation in uncontrolled airspace. We don't ask what type of airspace we're in during a flight under IFR. We don't particularly care if it's class A, B, C, D, E, G, etc.

If you're asking about the permission for making a high speed climb, the requirement for 250 knots below 10,000, where applicable, applies only if the minimum safe speed of the aircraft is below 250 knots. We don't need permission. We "ask" as a courtesy, for a high speed climb, but also often simply inform ATC about our climb speed. ATC expects it. The one exception will be times when a departure procedure may require a slower speed and a configuration change may be delayed because until those requirements are met, the SID or DP establishes the speed. At that point, our primary concern is meeting climb gradients and crossing restrictions.

An IFR clearance should normally keep an aircraft inside CAS. If a pilot is unable to comply with the clearance or SID for any reason, ATC would need to be informed.

My concern is that from what was written earlier, in some cases this apparently may not happen due to the lack of performance of a heavily laden aircraft. Pilots were warned that aircraft flying in Class G, and not in contact with the same ATC unit should be aware that they may suddenly be confronted with a "heavy" leaving CAS at 300kts below 10,000ft. The UK ANO specifically forbids this. SNS3Guppy seemed to be unaware of this UK rule. If he doesn't operate in UK (but I think he possibly does, after all the thread was opened by a UK poster) then I don't give two hoots.

[soaringhigh650]

An IFR clearance should normally keep an aircraft inside CAS

But if you look at most airports across the UK, a lot of IFR flight is done outside CAS. Some say this is a problem. Some don't.

[lucaberta]

ShyTorque, thanks for the clarification.

It would be interesting to know precisely in which specific case the issue of seeing an initial climb of a heavy B747 would infact fall outside CAS in the UK, mm_flynn mentioned Manston but I don't believe they operate a cargo facility there. I've seen B747 doing training flights there, yes, but that's a whole different ball game.

Interesting to see the difference between the FAA and the CAA interpretation of the rule. The FAA includes the "safety" aspect in the speed limit (which is also valid inside of CAS) whereby the UK only have outside CAS, and I guess it's mostly for see-and-avoid timing for aircraft with high closure rates.

Ciao, Luca

[ShyTorque]

Re. See and avoid, look back to the post by Roffa who quoted from MATS. There are a number of choke points in UK where a heavy failing to keep within CAS could cause a danger, especially at high speed.

[SNS3Guppy]

My concern is that from what was written earlier, in some cases this apparently may not happen due to the lack of performance of a heavily laden aircraft. Pilots were warned that aircraft flying in Class G, and not in contact with the same ATC unit should be aware that they may suddenly be confronted with a "heavy" leaving CAS at 300kts below 10,000ft. The UK ANO specifically forbids this. SNS3Guppy seemed to be unaware of this UK rule. If he doesn't operate in UK (but I think he possibly does, after all the thread was opened by a UK poster) then I don't give two hoots.

I do operate in UK airspace, actually, and I am aware of the regulation. Perhaps you're not.

http://www.caa.co.uk/docs/33/CAP393.pdf
CAP 393, Section 4, Rule 21:

Speed limitations
21 (1) Subject to paragraph (2), an aircraft shall not fly below flight level 100 at a speed which, according to its air speed indicator, is more than 250 knots.
(2) Paragraph (1) shall not apply to:
(a) flights in Class A airspace;
(b) VFR flights or IFR flights in Class B airspace;
(c) IFR flights in Class C airspace;
(d) VFR flights in Class C airspace or VFR flights or IFR flights in Class D airspace when authorised by the appropriate air traffic control unit;
(e) an aircraft taking part in an exhibition of flying for which a permission is required by article 80(1) of the Order, if the flight is made in accordance with the terms of the permission granted to the organiser of the exhibition of flying and in accordance with the conditions of the display authorisation granted to the pilot under article 80(6)(a) of the Order;
(f) the flight of an aircraft flying in accordance with the A Conditions or the B
Conditions; or
(g) an aircraft flying in accordance with a written permission granted by the CAA authorising the aircraft to exceed the speed limit in paragraph (1).
(3) The CAA may grant a permission for the purpose of paragraph (2)(g) subject to such conditions as it thinks fit and either generally or in respect of any aircraft or class of aircraft.

You've suggested several times that the only method of being exempt from the 250 knot speed limit below 10,000 is to have a written authorization, and this is untrue. That is one possibility, but only one of 7 categories of exemptions from the 250 knot limit.

Is the average private pilot willing to bet his life on compliance or a private pilot's understanding of the regulation, such that he or she insists on "sticking his fin" into the overlying airspace?

Take the case presented earlier of an engine failure after takeoff. We're goin to level at a predetermined altitude, to which ATC is not privy, and we are going to execute a turn procedure, also to which ATC is not privy. We will be dealing with cleaning up the airplane, accelerating to our clean airspeed on that heading (as given in our turn procedure), and then dealing with the problem (or problems), without any particular knowledge regarding the local airspace. In short, we have zero concern whether the airspace is class this or that, controlled or uncontrolled, and we'll resume working with ATC once we have handled our situation and stabilized it. Period.

Rarely is a high airspeed required when descending below 10,000, but in our case, nearly always it's required when climbing away after takeoff. We fly that higher airspeed too, including in the UK, given operational necessity. The only exception will be found in situations when a departure procedure requires a lower speed, such as is often the case in South America (185 knots is common), for the sake of turn radius.

Wouldn't Mr. Boeing already have talked to the CAA and gotten written permission for the whole 747 fleet, pointing to the AFM, SOPs and such?

Mr. Boeing is long since dead, but no, it doesn't work that way.

No need for SOP's. We have our performance, it's well known, and any operator of the type, including British Airways, will fly the minimum speed in the climb when heavy, which is V2 + 100 knots, and always above 250 knots. As a condition of operation, we do not need to abide a 250 knot limit in the climb, and we don't. Further, the regulation doesn't require us to.

During an emergency, of course, we will meet the needs of the emergency as necessary, which will include the clean climb.

If you need to do it, you still need written permission, or you are still breaking the law.

No, we don't require written permission, and no, we're not "breaking the law."

Again, I refer back to your prior statement that "I know one corporate operator who was warned off and threatened with further action for flying over 250kts." This operator did not have an operational need to be climbing above 250 knots, nor a clean speed above that value, did he or she? Of course not.

You seem very hung up on the possibility of a large airplane penetrating airspace frequented by light airplanes. Let me remind you that this is but one example of why vigilance is appropriate, especially when operating near controlled airspace. Those who would insist on their right to "stick their fin" in controlled airspace by flying directly against it should be made aware of potential conflicts. Despite your preoccupation with my clean climb speed, it's but one of many possible sources of conflict. My speed isn't the issue here; it's one's approximate operation to areas of potential conflict.

Yes, mode C may be inaccurate, especially in airplanes typically flown only under VFR. Yes, ATC compensates for standard atmosphere QNE output product from mode C, by correcting for QNH. Yes, altimeters can be off, and yes, separation can suffer. Yes, you can encounter conflicts with high speed and large traffic close to, and either side of boundaries, and no, you should never count on those boundaries to offer any sort of protection. One should not assume that one is free of trouble while skirting the ragged edges of busy airspace (or controlled airspace, for that matter).

No matter what your action or intent, always give yourself a margin, a buffer. You may need it. Plan accordingly.

[Roffa]

SNS3Guppy,

Forgetting emergencies and unusual stuff, this interested me...

No need for SOP's. We have our performance, it's well known, and any operator of the type, including British Airways, will fly the minimum speed in the climb when heavy, which is V2 + 100 knots, and always above 250 knots. As a condition of operation, we do not need to abide a 250 knot limit in the climb, and we don't. Further, the regulation doesn't require us to.

If you were flying out of LHR, where the SID says "Maximum 250KIAS below FL100 unless otherwise authorised" do you feel you should say anything to ATC before accelerating above 250kts?

ATC certainly would expect you to as the departure separations are predicated on the speed limit and I don't believe a BAW flight would accelerate without saying anything.

[SNS3Guppy]

If you were flying out of LHR, where the SID says "Maximum 250KIAS below FL100 unless otherwise authorised" do you feel you should say anything to ATC before accelerating above 250kts?

You bet, and we always notify ATC, as previously described in this thread.

[ShyTorque]

SNS3Guppy,

I'm fully aware of the rules regarding speed limitation, which is exactly why I asked you the question; I could just as easily have copied and pasted your quote from CAP393. You haven't answered my original question so here it is again:

Under what written permission do you exceed the 250 kt rule outside CAS?

In your earlier post you said that you do not care in what type of airspace you fly above 250 kts. Whatever your personal interpretation, the ANO is legally binding. It may not be in your place of main residence, but in UK it most definitely is. If you don't comply, you break the law.

A SID keeps the aircraft inside CAS, there is no issue over that.

I don't think anyone else intends to, nor mentioned "sticking a fin" into CAS, which is obviously highly stupid because as well as being dangerous it will always be investigated in depth and the CAA do prosecute pilots for CAS infringements.

However, UK airspace is very constricted in places and aircraft do need to fly in Class G under control areas. They have been given the perfectly legal right to do so. In much of the area under the London TMA, MSA sits right under the CAS (the CAS was designed that way) so it must be expected that aircraft will fly under the lower limit.

Sometimes transitting aircraft will be on a different frequency to the traffic climbing from an airfield, in fact this is commonplace around the London area. Not ideal, but that is the way it works.

If your heavily laden aircraft cannot make a normal climb gradient without breaking the terms of the ANO because it is unable to follow a SID inder normal circumstances, it must be overloaded.

Btw, I'm not merely presenting my personal interpretation of the ANO. Only last Friday I was under a traffic service in Class G and overheard a pilot ask the Birmingham Radar controller:

"Are you happy with our present airspeed".

Reply: "What airspeed do you have?"

"300 kts" came the pilot's reply.

The controller replied: "Not above 250 kts below FL100". I don't know if the other pilot was climbing or descending, or if he was inside or outside of CAS but that is irrelevant.

[Jumbo Driver]

Originally Posted by Roffa

SNS3Guppy,
ATC certainly would expect you to as the departure separations are predicated on the speed limit and I don't believe a BAW flight would accelerate without saying anything.

Of course, this is quite correct. The 250kts below 10,000' speed restriction in UK is normally relaxed for an "operational requirement". This means that a 747 departure at high weight (for example) will need to climb at greater than 250kts when clean to maintain an optimum climb gradient, as part of the normal operational profile. ATC will normally approve this as a matter of routine but it is a professional requirement to advise ATC at the time of requesting/receiving clearance.

In the example of a departure from EGLL at high weight, the EGLL departure procedures cover this in exactly this way, viz.

6. Departure Procedures
a. Standard Instrument Departure (SID) procedures for aircraft departing from London Heathrow Airport are detailed at AD 2-EGLL-6-1 to 6-7 and incorporate the Noise Preferential Routes (NPRs) detailed in AD 2.21.
b. Speed Limit: In order to optimise the departure flow and assist in the separation between successive departing aircraft a speed limit of 250 kt is applicable unless removed by ATC. ATC will endeavour to remove the speed limit as soon as practicable after departure, using the phrase ‘No ATC Speed Restriction’. Pilots are reminded that this phrase does not relieve the pilot of the responsibility to adhere to the ground track of the Noise Preferential Route, which may require a speed/power limitation.
c. If for any reason pilots are unable to comply with the 250 kt IAS speed limit the pilot should immediately advise ATC and state the minimum speed acceptable. If a pilot anticipates before departure that he will be unable to comply with the speed limit he should inform ATC when requesting start-up clearance, stating the minimum speed acceptable. In this case the pilot will be informed before take-off of any higher speed limitation.

Can we now get back to something more interesting and closer to the thread topic, please ... ?

JD

[SNS3Guppy]

I don't think anyone else intends to, nor mentioned "sticking a fin" into CAS, which is obviously highly stupid because as well as being dangerous it will always be investigated in depth and the CAA do prosecute pilots for CAS infringements.

Perhaps you missed post #64, when Mar1234 said "When the controlled airspace is 1000ft AGL, and I have little hope of a clearance, you can bet your last dollar I'm going to have my fin right up against the bottom of it. You might equally well ask why the professionals need fly so close to the base, and the wild, uncontrolled chaos that reigns beyond.."

The controller replied: "Not above 250 kts below FL100". I don't know if the other pilot was climbing or descending, or if he was inside or outside of CAS but that is irrelevant.

AGAIN, that controller wasn't speaking to an aircraft with a clean speed higher than 250 knots, was he?

He was not.

AGAIN, you're obsessed with the issue of speed here, when there are many aspects to the conversation, and the topic is mode C, not speed. You appear to have globbed onto one example, and appear to be unable to let it go.

Can we now get back to something more interesting and closer to the thread topic, please ... ?

Quite so.

[ShyTorque]

AGAIN, that controller wasn't speaking to an aircraft with a clean speed higher than 250 knots, was he?
He was not.

How do you know?

SNS3Guppy, you seem to be unable or unwilling to provide any answer to my question and prefer to divert the issue so regrettably, it appears pointless to discuss it further.

I'll have to assume you have no written permission.