Go Back  PPRuNe Forums > Flight Deck Forums > Rumours & News
Reload this Page >

speed control on final

Rumours & News Reporting Points that may affect our jobs or lives as professional pilots. Also, items that may be of interest to professional pilots.

speed control on final

Old 8th Oct 2002, 16:54
  #21 (permalink)  
 
Join Date: May 2002
Location: UK
Posts: 71
Likes: 0
Received 0 Likes on 0 Posts
Largely I agree with Lazlo,

Maybe what it needs is all this to be published on the plates as is done at some of the spanish airfields (with a bit more thought behind it however!) Something like maintain 180kts until 7 or 8miles then 160kts until 4, unless advised by ATC.

However, to quote my fleet manager in a recent aircrew notice "It's a touch of the tail wagging the dog!" In reference to the increasing number of constraints during descent, approach, landing and runway occupancy. A stablised approach is emphasised as the number one consideration, but to advise ATC if unable to comply with constraints.

I must own-up to being at fault here on occasion. 9 times out of 10 you call established and you get "descend with the glide and 160 until 4." (at Gatwick) So much so that i am guilty of doing it without being asked. As they say assumption is the Mother of all F**k-ups. Thanks for bringing it to everyones attention.

My eyes have been opened....
buttonmonkey is offline  
Old 8th Oct 2002, 20:45
  #22 (permalink)  
BOING
Guest
 
Posts: n/a
It looks as though the US has a slightly better way of communicating speed control than the UK. In the US you are told to "maintain a speed until advised" this speed is maintained even over frequency changes. On frequency changes the pilot adds "x knots assigned" to his check in. When you are "cleared for the approach" speed is at pilot's discretion unless a speed assignment is restated. This usually works quite well, no misunderstandings.

Having said that we are also being squeezed into the speed control box over here. Companies are requiring earlier stabilisation on the approach. Performance monitoring computers are becoming more common so it is more difficult to "cheat" even just a little. ATC is more frequently assigning speeds and these speeds seem to be required further down the approach. A while back our company reduced the flap speeds on all aircraft by ten knots from the manufacturers speeds to reduce flap fatigue so now it takes longer to slow down. All in all, it is becoming more difficult to meet ATC speed requirements and company (FAA approved) speed requirements at the same time.

Since the real problem is RELATIVE VELOCITY why do we not just use lower speed on all phases of the approch? What is so magic about 180 knots, just change to 160 knots at the same point. It will take longer and use more fuel but at least both pilots and controllers will be happy because the pilots will feel comfortable that they have their approch speed under control and the controllers get no more nasty surprises.

Sorry controllers, I am sitting in the seat watching the runway get bigger sometimes "you gotta do what you gotta do" to get the aeroplane on the ground - with you licence intact!
 
Old 8th Oct 2002, 21:44
  #23 (permalink)  
 
Join Date: Sep 1999
Location: United Kingdom
Posts: 929
Likes: 0
Received 0 Likes on 0 Posts
B757's Flap 30 (Full Flap) speed is in round figures 162 Kts.
Makes it D---m difficult in turbulance to take the full flap in time to be on speed (Vref +) and spooled up by 500 ft.
Unfortunatly the new QAR systems tell the management each time you are not, with often a visit to your boss.
So it is easier to slow down slightly earlier and hence avoid the interview.
Human nature I'm afraid.
+ whoever decided on 180/160 seems to have not understood a/c performance. (Note we SHOULD be configed spooled up and on speed by 1000')
IcePack is offline  
Old 8th Oct 2002, 21:52
  #24 (permalink)  
 
Join Date: Apr 2001
Location: a fence in the sun
Posts: 182
Likes: 0
Received 0 Likes on 0 Posts
I strongly suspect that this is (in part at least) outfall from the 'requirement' to fly CDAs. All these speeds are much easier to achieve if you don't try to achieve a CDA. Too much criticism of pilots will lead to their reverting to the old dive-and-drive style of approach, and whilst your speed control will work perfectly, the noise lobby will get uptight about it.

The last four approaches I have flown into LTMA airports all required use of speedbrake below 4000ft, and whilst flap was extended. The old adage goes: 'the speedbrake is there for my mistakes, not yours!'.

Controllers need to give us more room to manoeuvre, configure, and slow down.
NorthernSky is offline  
Old 8th Oct 2002, 22:47
  #25 (permalink)  
 
Join Date: May 1999
Location: Manchester UK
Posts: 27
Likes: 0
Received 0 Likes on 0 Posts
The Speed control 160 to 4 DME is managable in suitable conditions in a B757/767. However if you are asked to fly a Non Precision approach forget it. Our SOPS call for V REF speed at the FAF. So on a VOR App we will be flying at Flap 30 Speed 135/ 140 Kts at the FAF - 8 to 10 miles out to ensure a stable Non Precision approach. I will just do this ,and tell ATC about it when I have done it. Speed control is up to me - I am in command of the aircraft - I will decide what my crew can and cannot achieve. We also have QARS fitted and rushed / fast approaches are a real issue in my company. Slow down early is advice we are issuing to our crews to avoid GPWS and Go Arounds - both of which we have had in the last year due rushed approaches.
Lynx is offline  
Old 8th Oct 2002, 22:54
  #26 (permalink)  
 
Join Date: Mar 2002
Location: LONDON
Posts: 314
Likes: 0
Received 0 Likes on 0 Posts
I have started to handle B757s slightly differently. Knowing that they will be slowing early and then like a snail across the threshold I usually tuck them up a little on the one ahead and then stick an extra half mile behind. Same landing rate, everybody should be happy. The trouble is that we can't alter our technique to cover all types, there would be too much to remember. Oddly enough we were developing a machine that combined with Mode S would have done that for us... FAST.

We could all use lower speeds. Of course dragging in from12 miles at 150kts would cause increase in noise and fuel burn and some just won't do it, e.g. B773. We could open out the spacing and give each type more leeway but that would significantly impact capacity. (I have recently been involved in the debate over the B757 and what spacing should be given behind it. I have been told NATS argues that increasing the spacing will significantly reduce capacity and is against it. IT ALSO SAYS THAT SAFETY COMES FIRST!?)

I feel that a stable approach has to come first and capacity second. It is not our fault that we lack capacity and it certainly isn't our job to make up for it.

Point 4
120.4 is offline  
Old 8th Oct 2002, 23:05
  #27 (permalink)  
 
Join Date: Nov 2000
Location: Worldwide
Posts: 51
Likes: 0
Received 0 Likes on 0 Posts
I remember the 160/4 miles being standard at the OLD Singapore airport back in the early 1980's but we were flying 737-200's then before the rudder scares and the Flap 10 (Gear UP ) speed was 160. Unfortunately since the rudder scares our effective min GR UP speed is 170 and I would be failed on a line check for flying anything slower! I take the point regarding the 10 knot tolerance but when one is told " Change Director call-sign only!" it does not seem to be the time to add any speed requests in the initial call! The result of this will be more gear down flying on approach with a ten knot overspeed for Flap 15 (737-300) to achieve the 160 knots to 4D.
lost soul is offline  
Old 8th Oct 2002, 23:50
  #28 (permalink)  
 
Join Date: Dec 2000
Location: Samsonite Avenue
Posts: 1,538
Likes: 0
Received 0 Likes on 0 Posts
Lazlo

Going back to your previous post...

The legal minimum distance to which any speed control must be maintained to is 4D. So if ATC don't say otherwise, you must assume the restriction is to be maintained to 4D.

MG
Mister Geezer is offline  
Old 9th Oct 2002, 01:41
  #29 (permalink)  
 
Join Date: Feb 2000
Posts: 67
Likes: 0
Received 0 Likes on 0 Posts
Wink

geez us lads, what's all the fuss about....if u can't fly 160 to 4D in ANY boeing then it might be time to hang up your spurs......just ask anybody who flys for the any chance airline ( care to guess who?)
jammers is offline  
Old 9th Oct 2002, 02:49
  #30 (permalink)  
BOING
Guest
 
Posts: n/a
Trouble is Jammer that as I mentioned on an earlier post our company has knocked 10 knots off the Boeing speeds to reduce flap stresses. On the 757 we cannot take 30 flap until 152 knots. Sure you can fly an approach at 160 knots till 4D then slow to 152 and take full flap but the "snitch box" will have your "company defined" non stabilised approach recorded. It can all be flown but I would prefer to keep my licence.

Thank Heavens they never had "snitch boxes" on the 727. The reviewers would have had heart attacks!
 
Old 9th Oct 2002, 08:20
  #31 (permalink)  
 
Join Date: Oct 2000
Location: Berkshire, UK
Age: 79
Posts: 8,268
Likes: 0
Received 0 Likes on 0 Posts
Can some pilot please explain the answers to these conundrums, which have fascinated me over the years, more so after reading this interesting thread:

On the rare occasions when I am able to say "no ATC speed control" to someone on final approach it's more than evens that he will fly much faster than one of our "standard" speeds.

Why do so many 737s ask for 170kts to 4DME if some remarks on here are to be believed? I ALWAYS give them 170 now and adjust the spacing accordingly so am I doing something wrong? Not if one charmless pilot is to be believed - he was given 160kts recently and went bananas, even to the extent of moaning to the Tower man too.

Who was the BA pilot I met once who said he couldn't understand why we didn't always use 180 kts to 4DME to increase the landing rate? (In fact I believe that was being seriously considered as a standard procedure not too long ago).

I'm sure I've misunderstood the remark about 727s and the snitch box... I presume they actually wanted to fly much faster than our standard speeds? One crew flying a straight-in off LAM one morning doing 300kts+ asked what speed I wanted "No speed control" said I - so he said he'd keep "240 to the marker". In very, very recent times I've observed MD80s flying 280kts at 10DME and well over 200kts at 4DME.

As I think I've said elsewhere - ATCOs would love to sit back and do 5-6 mile spacing into Heathrow but it's YOUR employers who want us to thrash you guys in 2.5nm apart.

Lastly, I sympathise with you if the approach requires a lot of concentration but think about the final director - he doesn't just have to do it once; in one session he might land 50-60 of you guys and every single flight requires 110% concentration.
HEATHROW DIRECTOR is offline  
Old 9th Oct 2002, 09:48
  #32 (permalink)  
 
Join Date: Nov 2000
Location: Worldwide
Posts: 51
Likes: 0
Received 0 Likes on 0 Posts
Heathrow Director- I can understand your confusion because of the tone of some of the comments here (e.g. Jammers) This indicates the different levels of compliance with Boeing SOP's by different airlines! FACT- the minimum speed GEAR UP speed that can be flown using STD procedures on a "Classic" 737 (3-4-500) is 170 knots at Flap 10. I am fully aware that flying at 160 will not necessarily cause a crash BUT that is the speed that Boeing say to fly and in my airline that is what we do! The fact that some airlines are much less rigorous in their procedures is their concern but I'm not an aerodynamacist so I stick to the makers manual!
I hope that clears the air!
lost soul is offline  
Old 9th Oct 2002, 10:04
  #33 (permalink)  

the lunatic fringe
 
Join Date: May 2001
Location: Everywhere
Age: 67
Posts: 618
Likes: 0
Received 0 Likes on 0 Posts
On the rare occasions when I am able to say "no ATC speed control" to someone on final approach it's more than evens that he will fly much faster than one of our "standard" speeds
Lots of reasons.. If there is no ATC, no height or speed restrictions. The descent profile would be, Close the thrust levers at top of descent. Manage your speed, height, flight path, flaps and gear such that you spool up at 1000' aal in the landing configuration. ie. Thrust at idle from TOD to spool up. Very nice feeling if it all works out. Not too often with me! So 300kts at 20 miles 5000', bleed the speed off, run the flap, pop the gear, more flap and up comes the power. The speed is never static. On average it is faster and more efficient than with ATC speed controls. Some aeroplanes speed brakes are much more efficient than others. A "T" tail aeroplane has better speed brakes because the turbulance form the speed brakes does not impact the tailplane. So faster till later. The groundhugger let you deploy the reversers in flight. That slowed things up. So left to our own devices, the descent profile is very different to that witch ATC impose on us.

Why do so many 737s ask for 170kts to 4DME
The 737 has a fixed flap speed schedule. Flap 5 is flown at 170Kts. 160 needs Flap 10. Flap 10 is non standard. It should be after flap 5, Gear Down, Flap 15. And that is flown at 150 kts. Also a 737 will sit on a 3 degree slope at Flap 5, and 170kts and not accelerate, or decelerate... normally. Depends on the weight and the wind component. So for a 737 pilot 170kts is a good place to be.

Who was the BA pilot I met once who said he couldn't understand why we didn't always use 180 kts to 4DME
Indeed who is he! He sure never flew an A320/ 319s or a 747.

Lastly, I sympathise with you if the approach requires a lot of concentration but think about the final director - he doesn't just have to do it once; in one session he might land 50-60 of you guys and every single flight requires 110% concentration.
Eeeer this is a wind up? Yes? Or do you wish to open another thread entitled, "Pilots have it easy, ATC guys work for a living" We can deal with your point in that thread.

L337
L337 is offline  
Old 9th Oct 2002, 11:31
  #34 (permalink)  
 
Join Date: Mar 2002
Location: LONDON
Posts: 314
Likes: 0
Received 0 Likes on 0 Posts
Er, not entirely a wind up L337.

Yes, perhaps for a different thread but... Very few jockeys visit the Centres and I think some might be suprised.

The final director at Heathrow has an r/t loading measured at over 90%. That isn't planning or co-ordinating, it is just talking to the traffic, the rest comes on top. The clever bit about the job is not what you say but when you say it and that requires control of the r/t. It is amazing how quickly the FD starts swearing under his breath when he cannot get in or has to repeat. Now, we could relax, if you like, but you will be landing after midnight.

The need to keep traffic tight is what is making final speeds an issue and that leads us back to runway redundancy.

Point 4
120.4 is offline  
Old 9th Oct 2002, 11:43
  #35 (permalink)  
 
Join Date: Nov 2001
Location: Inside the M25
Posts: 2,404
Likes: 0
Received 0 Likes on 0 Posts
Couple of points here.

Firstly, although we requested 170 to 4 on the B737, in actual fact what we really need is about 170 to 7 - 'cos procedures were to have gear down and locked by 2000 AGL.

Secondly, the replier who remarked about 160 being flap 10 is out of date - as has been pointed out already, with the rudder problems, it is now 160/flap 15. 170 kts allows flap 10 (non-standard) and gear up.

Thirdly, for DIRECTOR and 120.4, please could you pass the word that, no matter how frustrated you are, there is no point in saying "one at a time please" when two people transmit - if we both start at the same time, then we have no way of telling that anybody else is transmitting.
Young Paul is offline  
Old 9th Oct 2002, 11:54
  #36 (permalink)  
 
Join Date: Nov 2000
Location: Worldwide
Posts: 51
Likes: 0
Received 0 Likes on 0 Posts
L337-- I'm afraid that you are out of date as I pointed out earlier! CURRENT Classic 737 speeds are F1 190k, F5 180, F10 170, F15 150. (F10 is not a standard config for landing but may be used as a minimum gear up config.)
lost soul is offline  
Old 9th Oct 2002, 12:56
  #37 (permalink)  

the lunatic fringe
 
Join Date: May 2001
Location: Everywhere
Age: 67
Posts: 618
Likes: 0
Received 0 Likes on 0 Posts
Sorry.



I should have remembered the earlier post about the change in 737 speeds. So 160 to 4 is even more of a pain than it use to be.

L337
L337 is offline  
Old 9th Oct 2002, 14:55
  #38 (permalink)  
 
Join Date: Nov 2001
Location: Inside the M25
Posts: 2,404
Likes: 0
Received 0 Likes on 0 Posts
Yes, but 170 to 7 and 150 to 4 would be ideal!!!!!!!!!!!!!
Young Paul is offline  
Old 9th Oct 2002, 15:26
  #39 (permalink)  
 
Join Date: May 2002
Location: uk
Posts: 165
Likes: 0
Received 0 Likes on 0 Posts
Vertigo

Just thought i'd add my 10 pence worth

160 till 4 can sometimes be difficult to achieve on the 737-800 due to it being very 'slippy' . I don't know which airport you operate at but we are 'generally' required to be 180 at 7, from there to to ruduce 160 till 4, this generally can only happen by ' gear down, flap 15', which is noisy for the locals. Perhaps a call to the aircraft of ' no less than 160 to 4 miles' would show that there is no room for them to slow further, were as ' 160 to 4 miles ' can ( but i know it shouldn't ) be misunderstood to be a max speed, therfore allowing a reduction .

It seems an easy problem to sove but it's obviously a widely misunderstood. Perhaps a word with the chart markers to add a note highlighting this problem, and a rewording of the speed control policy to leave no open interpretation of this speed rule.
brownstar is offline  
Old 9th Oct 2002, 16:47
  #40 (permalink)  
BOING
Guest
 
Posts: n/a
Heathrow director. When I mentioned the 727 it is not so much a matter of what the pilot wanted to do but what the aeroplane was capable of doing. With the 727 you could be at 250 kts on the glide slope eight and a half miles from the field and still be easily stabilised for landing at 1000 agl. At a push you could do better than that . Tons of drag when you needed to slow down. Comparatively speaking the 757 is a glider. You get very little drag till you get to 20 flap and the gear down. The 757 will barely descend on a three degree glideslope at 15 flap and no gear.

What this means is that you need much more space to configure a 757 than you did a 727 and similar ideas apply to the other aircraft types you mention. Each aircraft has an optimum way it can be flown if no ATC restrictions apply and that is what you are seeing.

Of course, there may be a little pilot "joie de vivre" involved in some of those approaches also!
 

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.