Slowing down on final approach.....

[Right Way Up]

Del Prado,
Just out of interest had you watched what his speed was before 4nm, because there is the chance they suffered some shear just before.

[Del Prado]

Intruder, he was stable by 1250' AGL. Isn't it reasonable to expect the stable approach criteria to be met closer to 1000' ie. an extra half mile before starting the speed reduction?
Don't many airlines allow approach to continue below 1000' if they're going to be stable by 500' and it's VMC?


Right Way Up, good point but I did monitor the speed throughout approach and didn't see anything to suggest windshear nor was windshear reported on the day.
Also the flight in question is typical of one where we start to get concerned with spacing/separation and was only meant as an example.

[Intruder]

My airline defines "stable" as

• Airspeed +5 / -0 kts from target.
• Aircraft is within, and tracking to remain within, the lateral confines of the runway extended.
• No unusual roughness or excessive attitude change after the middle marker. Pitch, power, and heading stabilized (not transient), and aircraft in trim.
• No more than 1/3 dot displacement from the localizer, and 1/2 dot displacement from the glideslope at 100’.

So, by 1,000' (500' VMC) the airspeed, pitch, and power must be stable -- I cannot be "stable" when 20 kt above target speed, or with power at idle and decelerating! Do you realize what it takes for an airliner to lose 20-30 kt while descending on the glideslope? Maybe the "light twins" decelerate in a heartbeat, but the heavies do not!

You did not mention whether the Easyjet was IMC or VMC. Neither did you mention the weather. Even if the airport was VFR, he may have been IMC at 2,000 or 1500', and would be following IMC procedures.

[Del Prado]

Thanks for that, I did mention above that it was more or less CAVOK (cloud ceiling was above 5000' and vis in excess of 10kms) that's partly why I'm querying the speed reduction on here. But you're right they could have been IMC in the scattered cloud reported at 2000'.

Do you realize what it takes for an airliner to lose 20-30 kt while descending on the glideslope?

I wish it took a mile longer, then this crew (and many more at Gatwick) would be complying with their clearance.


I'd take issue with your statement

Maybe the "light twins" decelerate in a heartbeat, but the heavies do not!

In my experience A320s, 737NGs and 757s aren't great at decelerating but DC10, Tristar, 747 classics all lose speed much more quickly.

[Roffa]

Intruder wrote:

Maybe if more Captains told ATC "unable 160 to 4; will be at 145 at 5" the ATC planners will rethink their restrictions that put expediency before safety.

ATC can accomodate whatever speed anyone wants to fly. Just always remember however that the pressure to get the maximum number of aircraft through the system comes from the airlines, your employers, not ATC.

We're reacting to your companies desires to fly ever more schedules and ultimately we'll do whatever you want. It makes no odds to me personally if the knock on effect is it reduces capacity, I'd welcome not having to work quite as hard!

[411A]

In my experience A320s, 737NGs and 757s aren't great at decelerating but DC10, Tristar, 747 classics all lose speed much more quickly.

The TriStar certainly will, if you close the throttles.

Oh dear, I can hear it now....shock, horror, close the throttles at lower altitudes, and die.

Well, this sure as heck was (somewhat) true with the engines on the 'ole straightpipe 707, but certainly not now, and especially not with airplanes powered by three shaft Rollers.

[FlyingCroc]

Please 411A

not again, the times of museum aircraft like Tristar and B707 are over. You can close throttles whenever you want but you have to be established at 1000ft, that means engines spooled up, regardless of engines make and models.

[West Coast]

Well said croc. Our body of work along with our collective experience and wisdom's will have minimal application in 30 years from now as aircraft and SOP's evolve. Just as those from 30 years past now try to provide with diminishing relevance. Learn what you can from the old timers, keep moving forward. There's a reason flying keeps getting safer. To give them credit, much of what we know is paid for in their blood. Many times we learn what not to do from some of the standards they used "back in the day"

[NigelOnDraft]

Thanks for that, I did mention above that it was more or less CAVOK (cloud ceiling was above 5000' and vis in excess of 10kms) that's partly why I'm querying the speed reduction on here. But you're right they could have been IMC in the scattered cloud reported at 2000'.

You guys criticise us when we "play ATCO", can we ask you not to second guess our SOPs IMC / VMC might be a factor for some airlines... but e.g. for BA it is not... i.e. we should always be stable prior 1000R (not 1000'aal for some reason either ).

Intruder, he was stable by 1250' AGL. Isn't it reasonable to expect the stable approach criteria to be met closer to 1000' ie. an extra half mile before starting the speed reduction?

Afraid not IMHO, it is very imprecise science, and the actual wind in the 1000'-2000' area, and more changes in that wind, need for Anti-Ice, crew experience / technique, and as you can see from this thread, the complete lack of training / instruction form airline in how to balance the contradictions of ATC and SOPs... but I know which ones gets me the phone call....

For all the ATCO whinging here, understandable, if it is such an issue how may reports have you submitted e.g. to BA "complaining" about our non-adherence? They certainly don't think it is an issue judging by the one way stream of material from them imloring us to slow down and be stable ever earlier... with pictures on unfortunate SWA 737's in gas stations

An Easyjet A319, instructed to do 160 to 4, is at 144kts IAS at 4 (1250' AGL) and still at 144kts at 1dme in more or less CAVOK. Why?

I am afraid such details are meaningless unless you also tell us his G/S exactly at the same instants... I am sure you appreciate that whilst you instruct us to fly IAS, and might think we do:

• Monsieur Airbus fits a random speed generator called "ground speed mini". Suggest you read up on it and if you understand it, please let me know
• Mr Newton III dictates the aircraft preserves G/S in varying wind, not IAS...

[BOAC]

I cannot believe this is still rumbling on. Now we are into 'I am 'elpless, it is zee French zat have done zis thing' technicalities.

You guys and girls can either do it or you cannot. If you cannot, say so. If it becomes a problem with traffic volume for ATC, I'm sure someone will notice. How many of the 'whingers' above have taken FORMAL action with their companies? Hands up?

I repeat maui's post #221

Beat your gums here as much as you like. It will not solve the problem. Pressure the people who can make a difference.

But above all, for all our sakes, if you can’t or won’t comply, SAY SOMETHING.

Maui

It is sound advice.