Tech Log The very best in practical technical discussion on the web

QNH 1050

Old 20th Jan 2020, 10:17
  #1 (permalink)  
Thread Starter
Join Date: Mar 2017
Location: everywhere
Posts: 198
QNH 1050

Current qnh at some fields in England have reached 1050. I understand this to be the limit for many aircraft altimeters. Any ideas what happens if it exceeds to 1051? Also i believe there is a regulation prohibiting ops in pressures exceeding 1049.8hpa.
A320LGW is offline  
Old 20th Jan 2020, 11:00
  #2 (permalink)  
Join Date: Jul 2006
Location: Somewhere over the rainbow
Posts: 839
I just checked in the FCOM for A320 and there is a procedure for operations at QNH above 1050. You can find it in PRO-SUP- miscellaneous: Operations at QNH Above 1050hpa.
Iím not familiar at all with this but they explained this is due to engine limitations on the nacelle and thrust reversers.
I would be interested to know more about it. =)
pineteam is offline  
Old 20th Jan 2020, 13:10
  #3 (permalink)  
Join Date: Sep 2007
Location: Windsor, UK
Age: 33
Posts: 268
For the A320 family, it’s in the FCOM.

PRO-NOR-SUP-MISC - “Operations at QNH above 1050hPa”.

Essentially you have to check whether you’re exceeding the flight envelope of -1000’ based on STD.

Otherwise, the procedures vary slightly depending on the fit of the aircraft. The old standby altimeters have to be set to 1050 or less with some mental maths added (in 100s of feet). The ISIS fit aircraft can all be set up to 1100hPa (although you’d likely exceed the flight envelope before getting anywhere near that!).

There is a slight amendment to the way the PERF page is set up and possibly a transponder procedure to apply too.

champair79 is offline  

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright © 2021 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.