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Hydraulic system loading

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Hydraulic system loading

Old 6th Jan 2022, 16:14
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Something seems to have been lost in translation when Airbus delivered the planes to the US. I've spoken to a few of my friends at different airlines, and nobody's ever heard of waiting for gear down to select F3. I restricted my survey to fleets of 100 planes or more, and it seems we have at least 1,500 planes moving gear and flaps simultaneously.

Now just because everyone does it doesn't make it right, but it doesn't seem like a death sentence either.
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Old 6th Jan 2022, 16:46
  #42 (permalink)  
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Originally Posted by Check Airman View Post
Hahaha. I think airbus technically refers to the various positions of the high lift devices as config 1, 2 etc


But I take your point
Yeah, in the middle of writing that, I remembered that that's what's also written on the control and the ECAM, so official Airbus-speak through and through.

Anyway back to the topic at hand, someone earlier cited Boeing standard procedure to call out "Gear down, flaps xx" simultaneously. But then someone else said it's prohibited. So what's the verdict?

As another data point, my manufacturer's (Bombardier, now Mitsubishi) manual does not specify, but my airline's manual says "gear down, flaps 30."
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Old 7th Jan 2022, 00:54
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Originally Posted by Check Airman View Post
Even for visuals. You can be a bit fast at 1000, but if you're not fully configured by 1000, automatic GA.

(and no, you can't cheat and reconfigure for a flaps 3 instead of full at 980ft)

What altitude do you use for visuals?
It seems really safe because in my company FOM states that on VMC ( they specified it in CEIL/VIS values , 1500'x5000m), you must be stabilized at 500' AAL. In IMC 1000'. Inependently on chosen type of approach.
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Old 7th Jan 2022, 01:32
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Originally Posted by Check Airman View Post

What altitude do you use for visuals?
Ok thank you!

Now, sadly we don’t do visual anymore as we only fly into Mainland China and it’s ILS everywhere in our destinations. Before the pandemic we were doing Visual in Fukuoka, Japan and we used 500 feet AAL as last gate same as Airbus SOP. For ILS and NPA we use 1000 AAL in any case.
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Old 7th Jan 2022, 02:04
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There's a difference in landing in VMC of IFR flight and landing of VFR visual circuit. Most IFR flights land in VMC but stabilisation criteria remain 1000ft. But íf you cancel IFR or cleared for a visual circuit/approach then it is 500ft. But now ATC asking for higher speeds like 160kt till four or five miles, in a light aircraft it becomes difficult to get the speed within the parameters. So, Airbus has suggested that only for speed and thrust the stabilisation altitude can be lowered to 500ft if the speed is decreasing towards the the criteran after approval from the authority. There's a video on this in Airbuswin.

Last edited by vilas; 7th Jan 2022 at 02:58.
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Old 11th Jan 2022, 16:36
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Originally Posted by Check Airman View Post
Thanks. This is exactly what I was looking for. I'll note 2 things though:

1. The response concludes with them saying there's no technical objection. I take that to mean the hydraulics aren't an issue.........
Well, actually Airbus said there is no technical objection to you selecting Conf 3 and Conf Full before lowering the landing gear.

Do we use TOGA on every take-off ? No because it will wear out the engines more quickly. So why move more than one big hydraulic service user at a time, (and put a big demand on the hyd pump), if you don't need to, (and Airbus SOPs do not require it)

Sideline gripe on linguistics and not hydraulics. I read this sentence: "The SOP philosophy regarding landing gear extension is to get it down and locked before reaching the final landing configuration..........."
It's not perfect English, but I think its meaning is very clear?. "Select gear down and wait to ensure it is down and locked before selecting any further config, e.g Conf 3 or Full, i.e. final landing configuration.
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Old 12th Jan 2022, 19:22
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Originally Posted by Uplinker View Post
It's not perfect English, but I think its meaning is very clear?. "Select gear down and wait to ensure it is down and locked before selecting any further config, e.g Conf 3 or Full, i.e. final landing configuration.
In the English I know, "final landing configuration" means the configuration in which you can land the airplane. (And just in case there's some uncertainty over potential multiple stages along the process of landing configuration, the phrase clarifies which stage, namely the "final" one.)
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Old 15th Jan 2022, 13:17
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Yes. Had they used the word 'selecting' instead of 'reaching'' in the quoted sentence:

"The SOP philosophy regarding landing gear extension is to get it down and locked before reaching the final landing configuration...........",

there would be no ambiguity
. English is not their first language of course.
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Old 16th Jan 2022, 02:09
  #49 (permalink)  
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Re Boeing “gear down, flap XX” from memory there’s a priority valve in the flap power control package that gives priority to the gear should the pressure drop below 2000psi, with two hydraulic pumps running this likely never occurs. With one then you may notice the flaps moving slower / stopping until the gear is down and locked and the pressure returns adequately to run the flaps.


Last edited by CCA; 16th Jan 2022 at 05:23.
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