170kt to 5 at LGW
 

I just wondered how everybody is getting on with the 170kt to 5nm trial at LGW?

No worries. Just fly two dots below the glide to 6d and then execute a 5g pull up to wash off the speed. (extending the gear and land flap as you do).

Maybe time to move some traffic out to the regional airports rather than compromise safety at the overcrowded London hubs dontchathink? Ah, but that would inconvenience the travel plans our our dearly beloved government employees mebee?

:ugh:

you can also config to gear down and F15 before 5NM, but keep the bug at 170. not very economic, but than you are already in a "drag" config when you come to 5NM, so the speed fades quickly and you can go to landing flaps.

Probably as allways depends on type or even variant. In a 737 800 i do not see any problem even with SOP required gear extension at 2000RA and 1000ft established (configures, checklist done, >40% N1). However in a -700 it is a completely different kind of game as Vrefs are so slow with usual values between 110 and 125kts (F30), nearly impossible to get that right with 170 to 5 if you have stringent SOP restrictions.

On a serious note (for which I am seriously not famous) 160 to 4d has been standard for a while. If asked to to 170 to 5d you still have a mile to lose ten knots to be back where we started. Anyone fly a type that struggles to do this?

What does this achieve at LGW? Surely it gives less chance to get the O/B's on their way??

At the higher weights, flaps 10 works too.

I believe this came about because airlines asked for it. At least that is what I was told happened at STN were the same 170 to 5 has been in use for some time now.

160 to 4 doesn't work on on our type because the F5/F10 speed is often in the 165K range. We don't lower the gear until 4nm on a standard low drag approach (weather permitting), so would have to lower the gear early (and waste fuel) to select F15 to comply with 160kts.

What about the well accepted 1000´ AAL establishment criterium (speed/rate/thrust/config)?

Or r u guys flyin Cessna´s and Piper´s around?

B738. Landing gate 500' VMC, 1000' IMC.

ATC recognizes this and understands the fact that on some aircraft gear and flaps would have to be extended to maintain 160 knots on the nose, resulting in a larger noise foot print to those on the ground.

With that being said 164 knots has not been and still is not a show stopper for traffic separation with traffic 4 to 5 miles ahead flying 4 knots slower, which equates to a closure rate of 1 mile in 15 minutes… or 404’ per minute.

Yep, I know that. But I have been told off by ATC before when their mode S readout showed I hadn't bugged 160k. In addition, the auto throttle in the Boeing has a tendency to fly on the fast side. This is due to the way the A/T logic works. Selecting 165 often results in the A/C flying around 170 kts.

170 to 5 gets around all of this just nicely.

Except that the traffic ahead is not flying at 160 kts any more, since they have slowed down to their final approach speed. If their final approach speed is 115 kts (and they started configuring early to get the speed off, as seems to be required on a light -700 according to earlier posters) and mine is 145 kts, that 10 kts extra speed to 4nm might just become a factor.

'continue approach, expect late landing clearance'

To maintain 170 to OM is very often required in FRA.

But flying the big bus it's not so easy to decelerate to Vapp, 'round 135 Kts, AND comply with profile stabilization criteria when required to maintain 170 to 5.

IRR I would be "surprised" if your Mode S reports "bugged" speed... If so, and this principle applied to an Airbus, ATC would have the delight of figuring out GS Mini ;)

Our Mode S shows actual IAS (and other parameters). The only "bugged" parameter it shows is Altitude/FL.

See FlitePartners Ltd - Mode S Elementary & Enhanced Surveillance (EHS and ELS) for a list of "Enhanced Mode S" parameters...

NoD

738 behind 319. Both supposedly flying 170kts. A 5 mile gap will rapidly turn into a no mile gap. Which is fun.

Nigel,

Quote from our ops manual:

But that came from ops, therefore not guaranteed to be technically correct. This exact wording was introduced in the ops manual in 2006. I'll ask some questions.

This site give good information about Mode S operations.

EUROCONTROL - Mode S Operational Overview

http://www.caa.co.uk/docs/7/DAP_SSM_..._Factsheet.pdf

Both documents state that ATC can interrogate selected altitude and Aircraft call sign.

Enhanced Surveillance

Mode S Enhanced Surveillance provides all the functionality of Elementary Surveillance but, in addition, it provides Data Link functionality and access to further DAPs. In order to achieve this, the aircraft must have an interface between the transponder and its avionics system. The additional DAPs available are divided into the following 2 categories:

Aircraft Current State Vector Information

The aircraft current state vector information indicates the current state of motion of the aircraft. The information available includes:

(1) Ground Speed.
(2) Track Angle.
(3) Turn Rate.
(4) Roll Angle.
(5) Climb Rate.
(6) Magnetic Heading.
(7) Indicated Air Speed.
(8) Mach No.


Aircraft Intention Information

Aircraft intention information may be available from the avionics to indicate the future path of the aircraft. This information may be displayed to controllers and used to enhance Safety Net systems such as Short Term Conflict Alert (STCA). The information available includes Selected Altitude and the Barometric Pressure Setting on which this is based.

My old airbus has a full flap extension speed of 175kt,and the athr is quite sloppy.160 to 4 was always better as you were not lowering flaps against the placard limit.We have had a lot of flap problems over the years and I wonder just how much of it can be blamed on the extra wear and tear from doing this.

Seems fine in the A321 so far. Gear just before 5 miles, and still passing 4 dme at 160kts or less.