A320 QNH Correction to V2
Joined: Oct 2007
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From: World
To have the proper answer you must check the Maximum Permissible Take Off Weight for the airport and runway in use. After that compare the speeds . Remember that no correction on speeds is required if applying bleed and qnh correction to flex take off. Refers to PER-TOF-TOC-20–10 P 5/14 “Correction produced on the RTOW chart” para 2 last sentence.
Thread Starter
Joined: Nov 2009
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From: PK
Thread Starter
Joined: Nov 2009
Posts: 195
Likes: 0
From: PK
To have the proper answer you must check the Maximum Permissible Take Off Weight for the airport and runway in use. After that compare the speeds . Remember that no correction on speeds is required if applying bleed and qnh correction to flex take off. Refers to PER-TOF-TOC-20–10 P 5/14 “Correction produced on the RTOW chart” para 2 last sentence.
Joined: Mar 2012
Posts: 2,605
Likes: 154
From: Having a margarita on the beach
Hi,
the reference is in PER-TOF-TOC-12-10 P 5/14 (TEMPERATURE ENTRY).
(...)Check that the resulting speeds are higher than the minimum speeds displayed on the RTOW
chart and that V2 is higher than the VMU limited speed (Refer to PER-TOF-TOD-25-20 MINIMUM
V2 LIMITED BY VMU/VMCA (KT IAS)).
(...)If OAT is higher than TVMC (line 3) or if the above speed check is not fulfilled, apply ΔW correction
from line 3 and ΔV1/ΔVR/ΔV2 corrections from line 4. No speed check is required.
Your speed are 149/150/151.
the reference is in PER-TOF-TOC-12-10 P 5/14 (TEMPERATURE ENTRY).
(...)Check that the resulting speeds are higher than the minimum speeds displayed on the RTOW
chart and that V2 is higher than the VMU limited speed (Refer to PER-TOF-TOD-25-20 MINIMUM
V2 LIMITED BY VMU/VMCA (KT IAS)).
(...)If OAT is higher than TVMC (line 3) or if the above speed check is not fulfilled, apply ΔW correction
from line 3 and ΔV1/ΔVR/ΔV2 corrections from line 4. No speed check is required.
Your speed are 149/150/151.
Thread Starter
Joined: Nov 2009
Posts: 195
Likes: 0
From: PK
Hi
The Note on the same page say: "No speed check is required for the first correction".
In any case the min V speeds on that chart are:
which are way below.
How did you determine that? You've only reduced V1 whereas the correction applies to all.
Hi,
the reference is in PER-TOF-TOC-12-10 P 5/14 (TEMPERATURE ENTRY).
(...)Check that the resulting speeds are higher than the minimum speeds displayed on the RTOW
chart and that V2 is higher than the VMU limited speed (Refer to PER-TOF-TOD-25-20 MINIMUM
V2 LIMITED BY VMU/VMCA (KT IAS)).
(...)If OAT is higher than TVMC (line 3) or if the above speed check is not fulfilled, apply ΔW correction
from line 3 and ΔV1/ΔVR/ΔV2 corrections from line 4. No speed check is required.
the reference is in PER-TOF-TOC-12-10 P 5/14 (TEMPERATURE ENTRY).
(...)Check that the resulting speeds are higher than the minimum speeds displayed on the RTOW
chart and that V2 is higher than the VMU limited speed (Refer to PER-TOF-TOD-25-20 MINIMUM
V2 LIMITED BY VMU/VMCA (KT IAS)).
(...)If OAT is higher than TVMC (line 3) or if the above speed check is not fulfilled, apply ΔW correction
from line 3 and ΔV1/ΔVR/ΔV2 corrections from line 4. No speed check is required.
In any case the min V speeds on that chart are:
which are way below.
Your speed are 149/150/151.
Only half a speed-brake
Joined: Apr 2003
Posts: 4,459
Likes: 136
From: Commuting not home
Haroon, you need to check with your Flight Operations Engineering department, and they probably with Airbus.
It makes no sense, and I think the explanations provided so far are valid for something else than you asked about.
To reiterate my understanding of your original question:
In case you needed to apply the speed corrections for low QNH, the resulting V2 is invalid. How come?
It makes no sense, and I think the explanations provided so far are valid for something else than you asked about.
To reiterate my understanding of your original question:
In case you needed to apply the speed corrections for low QNH, the resulting V2 is invalid. How come?
Last edited by FlightDetent; 23rd May 2019 at 14:54. Reason: undone auto-correct
Thread Starter
Joined: Nov 2009
Posts: 195
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From: PK
In case you needed to apply the speed corrections for low QNH, the resulting V2 is invalid. How come?
I would be grateful if some A320 pilots could have a quick glance in their books to see if they could find similar sort of stuff. Thanks.
Joined: Mar 2012
Posts: 2,605
Likes: 154
From: Having a margarita on the beach
Haroon, I haven't seen initially the minimum speed You have published, hence my answer does not apply to Your question. Best thing as suggested is to mail Your perf dept. and check with them.
Joined: Mar 2012
Posts: 2,605
Likes: 154
From: Having a margarita on the beach
) I believe it will end up by applying the corrections from line 3 and 4 so that V2 is not lower than Vr.
Thread Starter
Joined: Nov 2009
Posts: 195
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From: PK
The reply was:
"Software is designed to calculate Charts including speeds and corrections separately. After applying corrections if V2 decreases from VR then apply the basic performance rules and take V2 equal to VR."
"Software is designed to calculate Charts including speeds and corrections separately. After applying corrections if V2 decreases from VR then apply the basic performance rules and take V2 equal to VR."
