Speed Management/ Cruising Level
Thread Starter
Join Date: Dec 2017
Location: Europe
Posts: 5
Speed Management/ Cruising Level
Hi everyone,
I am wondering about pilot's preferences on speed restrictions . Let's say there's an aircraft (A320) at flight 360, cruising at M.74. Just behind him, there's another A320 climbing which has the same route and requesting FL360 while intending to take M.79. In this case, if my workload allows it, I ask the second one if he prefers to climb at FL360 with a speed restriction at M.74 maximum or if he'd rather stay at FL340 with no speed restriction. I've always felt like pilot prefer to fly without speed restriction, especially if the counterpart is a variation of altitude of 2000ft but what do they really prefer? Does it depend on each case/airline or is there some general rule that may apply? Is finding some middle ground (M.77 for both) a better solution?
Thanks !
I am wondering about pilot's preferences on speed restrictions . Let's say there's an aircraft (A320) at flight 360, cruising at M.74. Just behind him, there's another A320 climbing which has the same route and requesting FL360 while intending to take M.79. In this case, if my workload allows it, I ask the second one if he prefers to climb at FL360 with a speed restriction at M.74 maximum or if he'd rather stay at FL340 with no speed restriction. I've always felt like pilot prefer to fly without speed restriction, especially if the counterpart is a variation of altitude of 2000ft but what do they really prefer? Does it depend on each case/airline or is there some general rule that may apply? Is finding some middle ground (M.77 for both) a better solution?
Thanks !
Last edited by Shamrock2; 30th Dec 2020 at 21:55.
Only half a speed-brake
Join Date: Apr 2003
Location: Commuting home
Age: 43
Posts: 3,218
Similar aircraft would typically follow the restriction and keep their optimum flight level. The required mach adjustment cannot be that penalizing. Your example would be 78 - 76 with narrowbody Airbii in real life.
For different aircraft with larger gaps around .05 M the altitude trade becomes interesting. 2 above or 2 below is 4000. The winds could be quite different and that should enter the crew's choice. As well as what happens next, tactically. For instance, when going to the Canaries in peak summer, lower and faster is the preferred solution to skip the queue even if burning little more.
my 2p.
For different aircraft with larger gaps around .05 M the altitude trade becomes interesting. 2 above or 2 below is 4000. The winds could be quite different and that should enter the crew's choice. As well as what happens next, tactically. For instance, when going to the Canaries in peak summer, lower and faster is the preferred solution to skip the queue even if burning little more.
my 2p.
Join Date: Mar 2013
Location: EU
Posts: 495
I would say the general thought process of our lot (assuming the speed restriction isn't going to make us too fast or slow for comfort) would be to accept a level with a speed restriction if it kept us fast, or to take the lower level if the higher level would keep us slow. Maybe not so much if it's ~0.1-2 different from our requested, but I think most I work with would accept 2000' lower to take .79 over .74.
Join Date: Aug 2000
Location: Costa del Swanwick
Posts: 826
It depends on the length of flight. 4 hours of going faster/slower than optimum is very different than an hour or so. Fortunately most traffic is at pretty much similar speed nowadays not like a B733 @ FL350 @ .75 chased by a [email protected] that we had a few years ago.
Join Date: Aug 2000
Location: Costa del Swanwick
Posts: 826
Originally Posted by mike current
Stick them on headings and allow to overtake? (Sorry, stupid approach controller here).
Last edited by 250 kts; 2nd Jan 2021 at 13:25.
Only half a speed-brake
Join Date: Apr 2003
Location: Commuting home
Age: 43
Posts: 3,218
SLOP downwind for the heavy, 71 and. 82. Call me back when ready with your request to maintain own separation. Next ensuing report in 15 minutes.
(sorry, slightly wet dreaming pilot here).
(sorry, slightly wet dreaming pilot here).
Join Date: Feb 2010
Location: South EU
Posts: 52
My two cents: I would ask the slower ACF what increase in Mach # would he accept for spacing, and would offer that new Mach # to the second ACF. If he's happy with it, he will fly at F360. If I have the time, I also check their routes to see for how long the restriction would have to last.
Join Date: Oct 2014
Location: Ireland
Posts: 74
"Unavailable due traffic" - really though I would offer it but with the speed restriction. Normally however there's something better you can do like ask the guy in front if he wants a better direct, if he wants to speed up, or wants a different level. Then you're in the clear for the guy behind to level change without watching a tight gap.
In my experience pilots jump at the oppurtunity to speed up "yes sir any speed you want!", due to being limited to flying slowly due cost index calculations by the bean counters below. The newer A350's, 787's are brilliant for doing M0.86 or greater for spacing, they jump at it when we ask.
In my experience pilots jump at the oppurtunity to speed up "yes sir any speed you want!", due to being limited to flying slowly due cost index calculations by the bean counters below. The newer A350's, 787's are brilliant for doing M0.86 or greater for spacing, they jump at it when we ask.
Join Date: Jan 2011
Location: Earthville
Posts: 48
Originally Posted by Speed_Alive_V1
In my experience pilots jump at the opportunity to speed up "yes sir any speed you want!", due to being limited to flying slowly due cost index calculations by the bean counters below. The newer A350's, 787's are brilliant for doing M0.86 or greater for spacing, they jump at it when we ask.
Depends what mood I'm in as to whether I 'help'
Join Date: Sep 2010
Location: by the seaside
Age: 71
Posts: 969
Heathrow departures
Not FR but SR..early days of 250 knots departures were obliging to allow VNE to pass under Biggin stack which would knock a couple of minutes off our flight time.
Fokker 100 was a pain (thick wing no droop) as didn’t cruise at Mach .8 +, the Scandinavians soon got fed up, kept us low and out of the way.
Fokker 100 was a pain (thick wing no droop) as didn’t cruise at Mach .8 +, the Scandinavians soon got fed up, kept us low and out of the way.
Join Date: Mar 2014
Location: Way north
Age: 44
Posts: 473
Originally Posted by mike current
Fair enough. Seems sensible 
Only half a speed-brake
Join Date: Apr 2003
Location: Commuting home
Age: 43
Posts: 3,218
A couple of years ago a small group of ATCOs came to visit the SIM as a part of an educative assignment from the ANSP. Same age bracket as the two pilots we were, we made the most of it in a very clever and supportive atmosphere. RNAV and RVSM implementation had been the big thing around 5 years prior and a favourite examination subject when all of us received the ID badges for our respective parts of the airfield. Across the ranks we were keen and well educated on the subject, perhaps with some academic background too.
Given the local geography, typical morning departures from the capital would cross the national border at FL240 or continuous climb, having spent about 7 minutes with the lower ACC after leaving the TMA. I did not see the relevance of that when asking how would they deal with an air data sensor fault and UNABLE RVSM call from us at FL180 if there was a discrepancy during the required altimetry check.
Some lads at once opened their lips to start talking but awkwardly all remained silent for a small lull and then exhaled instead, before one of them after a little more contemplation came with a perfect answer.
I learned something about ATC that day.
Given the local geography, typical morning departures from the capital would cross the national border at FL240 or continuous climb, having spent about 7 minutes with the lower ACC after leaving the TMA. I did not see the relevance of that when asking how would they deal with an air data sensor fault and UNABLE RVSM call from us at FL180 if there was a discrepancy during the required altimetry check.
Some lads at once opened their lips to start talking but awkwardly all remained silent for a small lull and then exhaled instead, before one of them after a little more contemplation came with a perfect answer.
I learned something about ATC that day.
Spoiler
Last edited by FlightDetent; 16th Jan 2021 at 13:15.
