160kts to 4 miles? (LHR)
 

Could one of you superb controllers tell me if the 160 to 4 instruction could be modified/changed to 170 as I fly a B737 that requires the gear down flap 15 to achieve this speed sometimes from 4000 ft obviously noisy and very wasteful on fuel.
Comments please.

wardeep,

Probably not on a general basis, but on an individual one not a problem.

Please just mention the request in plenty of time ie just before base leg at the latest.

That'll give us enough time to build in the extra little bit of space required in front of you.

B.

Hi Wardeep. Discussions are taking place with a view to changing the standard speed to 170kts to 5DME but I understand that there are some major problems. It's very difficult to accommodate all preferences - Conc like 190, some of you guys prefer 170, 757s would prefer less than 160, etc. One or two airlines will happily do 200+ to 4DME!!!

I will always accommodate speed requests if they're given in good time, ie before the final turn onto the ILS. I always give 170kts to BMI 737s (and they generally indicate their gratitude) but have to admit that I do not know which other 737 operators prefer that speed. Eg I've always used 160kts for BA and last week I asked a BA 737 which speed he would prefer to 4DME, 160 or 170, he said "whatever you like" which leads me to believe that different types of 737 have different speed requirements. I always use 160 for all foreign 737 operators and none has ever queried it. An Air France 737 given "no ATC speed control" came back to walking speed and nearly caused a go-around!!

Any comments from 737 jockeys would be appreciated.

Most of the old 737-300's in the UK now have a min GR Up speed of 170. (Flap 10) It used to be 160 but the scare about rudder hard-overs changed that. I've flown these aircraft for two UK operators and both were the same. The next stage of flap (15) has a min speed of 150 but requires GrDn to avoid loud horns!! 767 and 757 use variable flap speeds with weight so at lighter weights can actually fly slower than the 737. Some operators of the NG 737's (700/800) use variable flap speeds from the Speed tape indicator so at light weights can meet your requirements with gear up.

"HEATHROW DIRECTOR"... "BURP"...B737 OPERATORS FOR THE PAST COUPLE OF YEARS HAVE BEEN USING A MODIFIED FLAP SPEED SCHEDULE...THIS...TO GIVE CREWS BETTER CONTOL MARGINS IN THE EVENT OF A MISBEHAVING RUDDER...CONTROLLERS CAN PROBABLY TAKE IT AS READ THAT B737 FLYING AT 160 KTS WILL REQUIRE "GEAR DOWN FLAP 15" A HIGH NOISE AND DRAG CONFIGURATION...170 TO 4NMS WOULD WORK BETTER FOR OUR A/C...TR3

You might want to have a look at this page from R&N a while ago.
Approach sequencing etc

TR3,

NO NEED TO SHOUT.

We'll happily accomodate whichever speed best suits but, as HD mentioned, if you offer the option of either 160 or 170 there is usually no consistency in the answer.

It's probably fair to say that 160kts suits the majority most of the time, but I reiterate, it is not a problem to accomodate something different provided the request is made early enough.

B.

Sorry "BURP" wasn't shouting just didn't release Caps Lock key on the keyboard...TR3 :p :p :p :p :p

Hi guys!
How about a procedure that could be initiated by ATC, and not the pilots having to ask for it. When traffic permits, the controller could issue a clearance that could sound like this: "Flight No., speed 160 to 175 to 4 dme". Not included in the clearance, fly the published speed. Could be on the STAR plate in the notes somewhere (if one can find room for it): "Fly published speeds. If able, controller will advise if higher speeds can be flown". Pretty busy out there at times, so let's find a way to reduce the r/t to minimum.
What do you think?

Flew into Gatwick yesterday afternoon and (without asking) got 170k to 4 DME! Someone muxt have been listening! Great!

The older types 737 do indeed require gear down and flaps 15 for 160 kts, but the NG 737 can fly 160 or close enough with flaps 5.

However, with the NG 737 and a little wind you could be looking at a minimum approach speed of 170 with flaps 30.
Strange wing design, eh?

Ready;

There is already something published to use. We can say disregard the speed OR issue another speed. It doesn't really matter what we publish, there is always going to be a pilot or two out there who is going to ask to do something else <G>.

Wish that I had a dollar for each time a pilot asked, is that pilot discression?

wardeep

It is my understanding that a speed instructed must be kept within 10 KIAS (ICAO). So if instructed to do 160 you may fly between 150 and 170. This may be different in the UK or at specific airports.

Skytalkert,

Speeds should be flown as accurately as possible. This is what it says in the UK ATC manuals. Any one not able to fly the assigned speed (give or take one or two knots only) should inform ATC ASAP.

This is especially true on the approach side of things, where 2 aircraft on the ILS instructed to maintain 160kts to 4DME, in trail on the ILS 2.5 miles apart, will cause much trouser browning if the second decides to fly at 170kts and the first decides to fly at 150. The further out on the ILS the aircraft are, the worse it becomes as the second a/c has more time to catch the first a/c up!

Certainly at Heathrow (can't comment on others) pilots should expect at least a go-around or maybe being broken off the approach and resequenced depending on exactly how close the two aircraft get!

AI

[ 11 August 2001: Message edited by: Aluminium Importer ]