Managed descent, altitude constraints, radar headings
CaptainMongo
I agree, this is not in line with the SOP. But years of experience tell me how easily we get distracted. A preset FCU can safe you lots of paperwork and explaining.
pineteam
Setting the speed bug below green dot or any min manouvring speed is a clear no go. Failing to set the flaps accordingly will put you below min speed which is unacceptable. Again it is distraction that can put you in a very tight corner here.
My general opinion: Setting up backup gates in your AP management does not hurt and can safe you from unpleasant experiences.
I agree, this is not in line with the SOP. But years of experience tell me how easily we get distracted. A preset FCU can safe you lots of paperwork and explaining.
pineteam
Setting the speed bug below green dot or any min manouvring speed is a clear no go. Failing to set the flaps accordingly will put you below min speed which is unacceptable. Again it is distraction that can put you in a very tight corner here.
My general opinion: Setting up backup gates in your AP management does not hurt and can safe you from unpleasant experiences.
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Um what? Since when was it unsafe to fly below F/S/green dot? I set the speed bug to the target speed.
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FlightDetent
I haven't had much opportunity to let the plane manage the decel. It's mostly impractical here in the US. The few times I have used it, it always seems to slow down WAY too early, and I wind up intervening so we don't drag gear and full flaps in from 10 miles out. I've tried it at local and foreign airports, and it always seems overly conservative.
I haven't had much opportunity to let the plane manage the decel. It's mostly impractical here in the US. The few times I have used it, it always seems to slow down WAY too early, and I wind up intervening so we don't drag gear and full flaps in from 10 miles out. I've tried it at local and foreign airports, and it always seems overly conservative.
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Gimbal Error you might want to check the FCTM. You can select speed below characteristics speed provided it’s above VLS + 5kt. It’s only at high altitude that you should not intentionally fly below Green dot speed. This is a common misunderstanding.
FCTM -PRO-NORMAL PRO- SOP-APPROACH
Like B2N2 mentioned beautifully: There is no substitute for experience.
If you were flying into China where ATC ask you to fly at 180kt nm 60 miles from touchdown and your S speed is 185kt you will get use to actually fly below S speed. It’s usually more than 25kt from VLS. Totally fine. Of course you can select flaps 2 but you will burn more fuel.
the 3 times I will definitely select speed below characteristic speed that I can recall are when:
I’m flying at 250kt and ATC asked me to reduce speed to 180kt ( again very common in China) I will immediately activate approach phase if not done already and select 180 kt and ask for flaps 1 at Green Dot and Flaps 2 if required. Yes you can do the Fcom way and managed speed when speed reaches Green Dot ask for flaps 1 and so on but doing so the engines will spool up and down. Not so great.
Second case it’s when I fly a very heavy A321 and green dot speed is less than 5kt from VFE. If VFE is 230 and Gd is 227 and you don’t select a lower speed the engines won’t be on idle and flying into turbulence or cloud you would easily overspeed. The safest way there is to select a speed below Green Dot, allowing the engines to go on idle and once the speed goes below Green dot with a speed trend going down then ask for flaps 1.
3rd case. Anytime during configuration if it will prevent thrust variation.
FCTM -PRO-NORMAL PRO- SOP-APPROACH
Like B2N2 mentioned beautifully: There is no substitute for experience.
If you were flying into China where ATC ask you to fly at 180kt nm 60 miles from touchdown and your S speed is 185kt you will get use to actually fly below S speed. It’s usually more than 25kt from VLS. Totally fine. Of course you can select flaps 2 but you will burn more fuel.
the 3 times I will definitely select speed below characteristic speed that I can recall are when:
I’m flying at 250kt and ATC asked me to reduce speed to 180kt ( again very common in China) I will immediately activate approach phase if not done already and select 180 kt and ask for flaps 1 at Green Dot and Flaps 2 if required. Yes you can do the Fcom way and managed speed when speed reaches Green Dot ask for flaps 1 and so on but doing so the engines will spool up and down. Not so great.
Second case it’s when I fly a very heavy A321 and green dot speed is less than 5kt from VFE. If VFE is 230 and Gd is 227 and you don’t select a lower speed the engines won’t be on idle and flying into turbulence or cloud you would easily overspeed. The safest way there is to select a speed below Green Dot, allowing the engines to go on idle and once the speed goes below Green dot with a speed trend going down then ask for flaps 1.
3rd case. Anytime during configuration if it will prevent thrust variation.
Last edited by pineteam; 14th Jun 2021 at 03:02. Reason: Added one sentence
My understanding is the ADS-B sends the altitude set in the window to ATC. Had another pilot flying the step by step way. Rhein Radar asked us to confirm the level we were descending to because it was different from what was in the window.
Only half a speed-brake
The last I flew was a -500 in '03 with U8.5 and it outperformed the Airbus VNAV 4:1.
I could provide a nice explanation why it is a desirable feature and not a bug if someone paid me to, still I hate it when it does what it does the best.
What you read above is folks feeling the same and trying to tweak it. Back before now, choking the throttles did the trick although it was seldom needed.
I could provide a nice explanation why it is a desirable feature and not a bug if someone paid me to, still I hate it when it does what it does the best.
What you read above is folks feeling the same and trying to tweak it. Back before now, choking the throttles did the trick although it was seldom needed.
Last edited by FlightDetent; 14th Jun 2021 at 03:33.
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I never flew Boeing but I have to admit. The A320 predictions are heavily conservative. If I’m not seeing “more drag” or the v dev at the bottom of the scale on PFD then I know I’m too low already for an idle approach xD.
Only half a speed-brake
Check Airman
We need pictures. The question is - how bad can the crew meals get before the table becomes irrelevant and the wish for an airplane with movable throttles resurfaces.
We need pictures. The question is - how bad can the crew meals get before the table becomes irrelevant and the wish for an airplane with movable throttles resurfaces.
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SFO guys who flew Boeing into the boundary wall found Thrust hold complicated. Dubai guys who tried a go around after touchdown and came crashing down never knew that autothrottle/FD is inhibited. Complications never end.
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ATC here - with modern Mode-S downlinked aircraft parameters, we can see your MCP selected altitude downlinked to your aircraft coupled tag on our radar screen.
If your downlinked level is different to the cleared level that we have selected, a breakthrough warning message pops up and we will say over RT "confirm your cleared level is FL100" etc. It's a really great tool to prevent level busts. The other day I said "Climb to FL230" which was readback correctly, but FL320 was set in the MCP. Error message, inquire with crew, error fixed. Level bust prevented 10,000 feet below where it might have been an issue.
Anyway just a point to say, I don't think I've ever seen this radar warning about a selected level above your cleared level, when speaking about meeting ALT contraints. But I'm in EASA land. I can see the benefit of changing your MCP alt when approaching the waypoint to the next FMC alt, as long as it's all above your cleared level, but just a note from the ATC side that I don't often if ever see it happen. Unless your Mode-S output is deceiving us
If your downlinked level is different to the cleared level that we have selected, a breakthrough warning message pops up and we will say over RT "confirm your cleared level is FL100" etc. It's a really great tool to prevent level busts. The other day I said "Climb to FL230" which was readback correctly, but FL320 was set in the MCP. Error message, inquire with crew, error fixed. Level bust prevented 10,000 feet below where it might have been an issue.
Anyway just a point to say, I don't think I've ever seen this radar warning about a selected level above your cleared level, when speaking about meeting ALT contraints. But I'm in EASA land. I can see the benefit of changing your MCP alt when approaching the waypoint to the next FMC alt, as long as it's all above your cleared level, but just a note from the ATC side that I don't often if ever see it happen. Unless your Mode-S output is deceiving us
I would like you to imagine this kind of day out and offer your views on the situation particularly with regards to automation, trust in automation, monitoring, ATC.
Monitoring is so important, across all timescales; FMAs all the way to re-routes. As soon as you start to deviate laterally or vertically from plan *anywhere*, it’s essential to project the flight path forward as far as is practicable. It may be of no consequence whatsoever but it is easy to paint yourself into a corner before realising it.
ATC bear a heavy burden when it comes to keeping the flight path of an aircraft safe, but as the guys at the front you have the ultimate responsibility and suffer the consequences of any mishaps in a very personal fashion...
Luckily, for me, Australia is not overly busy, and the STAR’s have improved somewhat with many joining RNAV-X (RNP-AR’s). These have built in slow downs, so now, if there is no ATC intervention, the whole thing can be flown managed and flap taken on speed all the way to the threshold.
It’s a beautiful thing to behold.
What’s even more fun is to watch the F/O (or Check Capt) squirm because I haven’t played the FCU like Billy Joel the whole way down to follow the Managed DES and SPEED all the way to the Threshold, taking flap as required. 😂
But, when ATC get involved, a simple 3x calculation, and a liberal use of Speed Brake usually does the trick.
As to the OP’s question, SOP’s allow the dialling in of cleared ALT, if we are then instructed to turn off the STAR/level off, new HDG/ALT is to be entered on the FCU. (In this case, I would usually enquire if the ALT restriction still applies)
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FWIW, my company's version of the FCTM (B737 and 787) tells us to only select the next step down altitude in the MCP once you're sure the current constraint will be respected, either due to ALT HOLD or the altitude trend indicator. So in case of a "descend via" clearance, we're still supposed to set all stepdown altitudes in sequence. Same for climb restrictions.