Why do eJ and Go fly at 250kt below FL100? [Archive]

EGGW

23rd Oct 2002, 15:27

As far as i'm concerned its a daft SOP. climbing at 250 kts will produce high rates of climb, if the V/S isn't reduced, TCAS TA's and RA's can be produced.
I had some nice gents on the F/deck from LATCC recently, who complained about the Easy SOP, and agreed that acclerating to speeds above 250 reduced rates of climb, as most aircraft would be acclerating below the stacks at BNN, LAM for instance. TA's etc would be reduced in all probabilty.
Obviously turbulence speeds have to be obeyed, when needed.
I believe JMC do the same, please correct me if i'm wrong.

FlapsOne

23rd Oct 2002, 15:49

I believe it's to do with minimising the effect of a birdstrike.

Most aircraft I have flown over the last 23 years have had some guideline or other concerning birdstrike risk, although that was normally below 8000'.

EZ decided, about a year or so ago, to raise this to 10000' and introduce it as an SOP.

Don't know if the decision was based on any specific data.

Rates of climb and descent can be adjusted using V/S to eliminate nuisance TA/RAs but, if this is a big issue, why not write to EZ and seek clarification?

411A

23rd Oct 2002, 15:52

EGGW,

Daft SOP you say?
IF you have ever hit a bird(s) at high speed, you might just have a different perspective.

If it is a big enough bird (or a large flock), the results are not pretty...:eek:

The Grim Reaper

23rd Oct 2002, 16:03

In the Boeing manual the speed restriction applies if the window heat is inop as the windows are more likely to break with a birdstrike (less flexible when cold).

Wouldn't the birds find it more difficult to catch us at 300kts? ;)

PS Breaking the SOP can result in disciplinary action from the company!

lomapaseo

23rd Oct 2002, 16:04

Most birds above a 1/2 kilo will do plenty of local damage to most aircraft structures (except windscreen} at 300 kts or higher (at the min expect at least a hole) between 250 and 300 kts expect a big dent as min damage.

The engines won't much care as long as they are at climb power or more, but if at reduced power for approach they may have substantially increased the chance of damage downstream of the fan.

kinsman

23rd Oct 2002, 16:09

Out of interest 250 kts below 10000ft is the law in the US, ATC cannot clear you to go faster end of story!

It is not such a daft SOP for the reasons already mentioned and high speed below 10000ft can sometimes lead to rushed and unstable approaches. Now I know we are all aces but it does happen.

We as a company also have 250kts below 10000ft as an SOP but an SOP is not a restriction. If briefed, requested by ATC, or operationaly makes sense on the day given weather etc, you can fly faster. Question is how much time and fuel do you save? the answer is not very much.

Since the introduction of OFDM folks have tended to be much more measured in the way they operate the aircraft. The passenger just want a smooth ride after all.:cool:

canberra

23rd Oct 2002, 18:00

ive always been under the impression that only the military can fly faster than 250kts below 10000' am i wrong?

fmgc

23rd Oct 2002, 18:11

Sometimes it is nice to be able to go faster to get the height off so as to not to lead to a rushed approach.

A classic example is suddenly being given a left base to 26 at LTN by the helpfull LATCC people, you really do need high speed to get the height off.

(Before I get the usual argument about having to lose the speed when level so there is no advantage to high speed, lets not forget the square rule)

Spitoon

23rd Oct 2002, 18:35

For canberra and others, in the UK Rule 23 is the one that matters for speed.

(1) Subject to paragraph (3), an aircraft shall not fly below flight level 100 at a speed which according to its air speed indicator is more than 250 knots unless it is flying in accordance with the terms of a written permission of the Authority.
(2) The Authority may grant a permission for the purpose of this rule subject to such conditions as it thinks fit and either generally or in respect of any aircraft or class of aircraft.
(3) Paragraph (1) shall not apply to:
(a) flight in Class A airspace;
(b) VFR flight or IFR flight in Class B airspace;
(c) IFR flight in Class C airspace;
(d) VFR flight in Class C airspace or VFR flight or IFR flight in Class D airspace when authorised by the appropriate air traffic control unit;
(e) the flight of an aircraft taking part in an exhibition of flying for which a permission under article 61 of the Order is required, if the flight is made in accordance with the terms of a permission granted to the organiser of the exhibition of flying under article 61
of the Order, and in accordance with the conditions of a display authorisation granted to the pilot under article 61 of the Order; or
(f) the flight of an aircraft flying in accordance with the â€˜A Conditions' or the â€˜B Conditions' set forth in Schedule 2 to the Order.
In simple terms, if you are flying in airspace where other pilots may be flying VFR and aren't getting some for of ATC surveillance and traffic information, the limit is 250 kts.

Outdated rules? Yes probaby. A bit too simplistically summarised above? Yes probably, but that's what it seems to boil down to.

YouNeverStopLearning

23rd Oct 2002, 18:37

Canbera:

In answer to your question, you are wrong.

In class A airspace in UK you can fly above 250KIAS below 10,000'. This of course is notwithstanding any other speed restrictions, ATC, etc...

...except of cause Ryanair, who fly above that speed anywhere they like, particularly into Prestwick when they’re late, i.e. OFTEN.

filejw

23rd Oct 2002, 18:47

I think the 250 rule dates back to the mid 60's.After two midairs the FAA thought it would enhance the ability to see VFR traffic..:)

kinsman

23rd Oct 2002, 19:17

FMGC depends how close in you are! You are often better to slow down and config, then use speed. Depends on the day but leaves you better placed for a stable approach, most times. All depends on the day I guess.

Raw Data

23rd Oct 2002, 19:49

As a matter of interest, often the weakest part of the forward structure is not the windscreen, but the fuselage structure immediately above the windscreen- plenty of aircraft (including at least one 737) have had holes punched in the this area due to birdstrike.

Many moons ago, a F/O was killed after a bird entered the structure just above his windscreen...

411A

23rd Oct 2002, 19:54

Personally viewed the damage a large bird can do to a jet transport in Khartoum years ago.
A buzzard was struck by a Boeing 727 at 4000agl, and the bird went,
thru the radome, forward pressure bulkhead, broke the First Officers left leg, went thru the cockpit door, and what was left of him was splattered all over the first class lounge.

The aeroplane was doing 340 KIAS at impact.

Definately not pretty.

FlapsOne

23rd Oct 2002, 20:17

The Grim Reaper

If a bird chases me when I'm doing 300kts, and shows the slightest chance of catching up, then hitting it is the least of my worries !!!!!!!!!!!!!!!!!!!!

Engee73

23rd Oct 2002, 22:18

I think it is because the aircraft are only certified to withstand bird damage up to 250kts (no testing after that) and also that the risk of birdstrike (worldwide) is low above 10,000 ft therefore as EJ has suffered a few birdstrike problems it has been decided that safety is more important than the economy or expediencey and that is now the SOP.

I would prefer something like 'above transition' but hey, they don't ask me!

Seriously though is it that hard for a controller to ask for high speed rather than cancel speed seeing they seem to know (and have been advised) what we do?

If you have further issues about this why not contact the company ATCers who I'm sure would be happy to discuss work arounds.

in the meantime feel free to ask me to go fast! ;)

NG

sfomarc

24th Oct 2002, 00:32

From a company stand point you are going to burn a whole lot less gas at 250 then at 300kts. Why go 300kts in the oposite direction?

mainecoon

24th Oct 2002, 00:33

nice idea iomapaseo

but to prove you wrong

nimrod (raf maratime patrol aircraft based on the comet(first jet airliner)) on departure from kinloss scotland due injestion of birds in i believe 3 out of four engines freinds of mine had fathers either injured or worse so think again about your turbine integrity

ps i was told whil'st working fishery protect aircraft that diving birds (oops) become blind in old age
we struck one of the such in our fk27 damage to starboard side after shredding by prop and also radome underside

ps if you route outside regulated airspace (in my case into the vale of york) more than 250 below 10000 is up to you it's in the aip so don't ask

lomapaseo

24th Oct 2002, 01:59

>nice idea iomapaseo

but to prove you wrong

nimrod (raf maratime patrol aircraft based on the comet(first jet airliner)) on departure from kinloss scotland due injestion of birds in i believe 3 out of four engines freinds of mine had fathers either injured or worse so think again about your turbine integrity<

I fail to see how this proves me wrong.

Aircraft at high speed and birds do not mix well

http://images.prosperpoint.com/images/2245/113295-221.jpg

Hippy

24th Oct 2002, 06:52

mainecoon:
ps if you route outside regulated airspace (in my case into the vale of york) more than 250 below 10000 is up to you it's in the aip so don't ask

I've got to ask - Are you sure about that?

ps not related to canberra are you

eyeinthesky

24th Oct 2002, 08:46

Some odd assumptions from my ATC colleagues in places.

'No ATC Speed Restriction" means just that. You are not limited to, for example, 250 kts on departure from KK/LL. You can speed up if you wish to, but you don't HAVE to. Indeed, if speeding up means you will not make the SID low level restrictions or 'level by' expectations, then don't do it. Likewise, if you are given 'No speed' on arrival and then end up unstable on the approach, that is your fault, not ours! (This excludes ATC instruction to fly a specific speed (e.g. 160 to 4)).

The fact that many airlines accelerate to 300 kts on departure once derestricted should not mean we expect them ALL to and then get caught out when they don't.

Mainecoon: 250 kts below FL100 in Class G is the LAW, it is not 'up to you'! Like all these things, you break the law at your own risk.

Ref birdstrikes: Aren't you supposed to give way to unpowered aircraft?!:D

outofsynch

24th Oct 2002, 09:53

Definitely a lot lest stressing, but a lot less fun too!

Having flown both sides of the argumnent b4 Go joined Easyjet SOP, I think it has more to do with stability of approaches etc. I have seen far less 'sweat' since we changed procedure, and as already said it makes stuff all difference in flight time.

What I cant understand, is why the restriction on departure/climb? When it could save quite al lot of time on some of the CPT departures and associated hold-downs.

I guess its just standardisation.

What amazes me is why ATC continue wasting radio time with 'no atc speed' when they know we can't increase?

acm

24th Oct 2002, 11:55

EGWW, your rate of climb at 300kts would probably be the same than at 250kts. Only the angle of climb will be affect. So if you want to avoid TA/RA you should control your V/S not your IAS.
What do we gain in term of time and fuel by flying faster than 250 kts below FL100 ? (1 minute maximum and probably burning more fuel)
Bird strike (square root of the speed ?) and encounter with VFR traffic is a bigger issue and that why 250 kts below 10'000 is a good SOP.
I heard that easyJet introduce this SOP after one of their aircraft had GPWS warning a couple of year ago in high terrain south of LPL, descending at 300 kts or above ?

LordLucan

24th Oct 2002, 12:15

As well as bieng a company SOP the airspace around EGGD is 250 kts < FL100 and that is non negotiable.

Sorry if it slows down you boy racers, however it certainly cuts down the number of rushed approaches FLIDRAS picks up and that can only be a good thing !

:D

Ace Rimmer

24th Oct 2002, 15:42

Just flipping back to the FAA 250kt restriction. I understand that there was a trial going on at KIAH with the limit being raised to 300kt for departing a/c... something to do with improving flow or some such...anybody know what happened to that?

Anthony Carn

24th Oct 2002, 20:45

A large proportion of the time I don't increase climb airspeed when given "no speed control". 250 kt gives me a good rate of climb above the frequently present turbulence, however light or otherwise, in the lower levels. Any acceleration kills rate of climb almost dead for that period of acceleration. Cu clouds are a good guide. Above the tops, I'll take the "no speed" concession, though it's usually not even worth the effort of dialling it in by then, since PROFILE gives acceleration at FL100 anyway.

Operation from Heathrow, Luton and the like, which I don't do much of these days, is the exception, when acceptance of a longer period of poor ride during the early climb, in order to clear the inbounds, may well prevent a longer period of level flight in the self same turbulent lower levels. An even better option is the "give you a good rate" call which used to (still does?) get hot(ish) ships above the inbound traffic and the turbulence and may well mean LESS than 250kt for a quick "zoom"(energy exchange). Body angle, for comfort but mainly cabin crew, is the limitation in this case.

So my deciding factor is ride quality, basically.

Descent depends upon many more factors, not least getting the height off in these slippery modern ships.

All IMHO -- more than one way to skin a cat as the previous posts demonstrate.

eastern wiseguy

24th Oct 2002, 22:11

What amazes me is why ATC continue wasting radio time with 'no atc speed' when they know we can't increase?
Probably because the next guy in the line will ALWAYS ask "any speed control for the Midla*d xxx?" .We know the rules at LEAST as well as you guys:D and it does become a bit of a habit.

NudgingSteel

24th Oct 2002, 23:09

as a couple of people have mentioned, "no ATC speed" from approach control, means no requirement to fly a certain speed to fit in with our radar sequencing or vectoring - usually the traffic is light enough or spaced in such a way that the gaps on final will never get too tight. I know this comes up time and again, but the phrase doesn't override the 250kt requirements of the UK AIP. For example, Class E airspace round Belfast and the Scottish TMA is a see-and-be-seen environment in which VFR traffic (and fast jets occasionally not transponding) legally operate without speaking to ATC, and not always showing on radar. Therefore your 737 has to give way to the hot-air balloon or microlight at 5000' somewhere ahead of you... Consider this if you fancy keeping high speed all the way down!!!!!!

Also, by us not imposing a particular speed, doesn't this allow for a more efficient approach profile and/or slightly less cockpit workload?

break dancer

25th Oct 2002, 09:18

Isn't there something in the go/ easy manual about a requirement to increase speed to to 280 kts if turbulence is forecast for the departure, and being able to reduce to 250 kts if below MLW? Which SOP takes precidence, besides common sense.

Also, how long before FLIDRAS will pick up infringements of greater than 250 below 10,000 with disciplinary action to follow?

Few Cloudy

25th Oct 2002, 09:25

So what is different in the sky below FL100? (10,000ft for the States guys).

a) Traffic slowing for initial approach anywhere from Fl60 downwards.

b) Traffic off-airways being vectored or on a standard SID or STAR or positioning for one.

c) Lots of Indians - Navajos, Cherokees etc.

d) Helicopters.

e) Police flights.

Anyway - a lot of traffic. The same applies here as when you drive your car - the slower you go, the more time you have to get out of trouble. That is the basic reason why not only easy/GO but quite a lot of other airlines have the 250kt restriction. That is a company SOP.

Having said that, I can understand that the ATC have have me out past his holding stack faster (Lambourne for example) if I can speed up, then I can be given an earlier climb etc. If he has the situation under control and asks me - and the SOP allows for this case - fine.

The other case - the rapid descent - works well with all the drag that the airframe produces at high speed and if planned and followed up properly gives time to reduce speed for the final turn on. This also requires a hands on attitude by ATC - as the ship is descending into ever more populated airspace at high speed and rate.

My personal thought is that it is very satisfying (fun as one writer put it) to use the speed to get in and out but it is demanding of all involved. There are times to accept and times to refuse - you can't generalise - and the SOP allows for this.

A further thought is that it would be very useful for ATCs to be supplied with this part of airline SOPs, so that forum queries should not be needed.