Sponsor Message:
Aviation Technical / Operations Forum
My Starred Topics | Profile | New Topic | Forum Index | Help | Search 
Pressure Error  
User currently offlineNovice From United Kingdom, joined Aug 2012, 90 posts, RR: 0
Posted (1 year 5 months 1 week 4 days 1 hour ago) and read 2481 times:

Can someone explain pressure error? in regard to one of the altimeter instrument errors

Cheers

2 replies: All unread, jump to last
 
User currently offlineflyingturtle From Switzerland, joined Oct 2011, 2035 posts, RR: 13
Reply 1, posted (1 year 5 months 1 week 4 days ago) and read 2481 times:

Altimeters should be pretty reliable... except some wasps decide to occupy the static port.

Does your question relate to pressure altitude? Temperature differences can cause wrong altimeter indications. Or do you mean the difference between QNH (standardized altimeter setting to maintain vertical separation between aircraft) and QFE (the correct altimeter setting in regard to the ground)?


David



Keeping calm is terrorism against those who want to live in fear.
User currently offlineJetlagged From United Kingdom, joined Jan 2005, 2532 posts, RR: 24
Reply 2, posted (1 year 4 months 4 weeks 1 day ago) and read 2481 times:

Pressure error is the difference between sensed air pressure (static or pitot) and freestream pressure (static or total) . This occurs because the local airflow affects the pressure around the port. In relation to an altimeter it means that the sensed static pressure will give an incorrect altitude reading unless it is corrected. Air Data Computers have correction tables based on flight test data which apply a correction to the sensed pressure to give a corrected pressure, from which the indicated altitude is derived.

On some aircraft if you select alternate static source in flight you get an uncorrected pressure measurement (or perhaps a less sophisticated correction) which means the indicated altitude jumps to a new value.



The glass isn't half empty, or half full, it's twice as big as it needs to be.
Top Of Page
Forum Index

Reply To This Topic Pressure Error
Username:
No username? Sign up now!
Password: 


Forgot Password? Be reminded.
Remember me on this computer (uses cookies)
  • Tech/Ops related posts only!
  • Not Tech/Ops related? Use the other forums
  • No adverts of any kind. This includes web pages.
  • No hostile language or criticizing of others.
  • Do not post copyright protected material.
  • Use relevant and describing topics.
  • Check if your post already been discussed.
  • Check your spelling!
  • DETAILED RULES
Add Images Add SmiliesPosting Help

Please check your spelling (press "Check Spelling" above)


Similar topics:More similar topics...
The Reason Of Calculating Pressure Altitude posted Thu Sep 6 2012 07:26:14 by mawingho
Pressure And Density Alt posted Sun Jul 1 2012 11:42:51 by smartt1982
Scrapped High Pressure Turbine Blades posted Thu Mar 22 2012 14:38:04 by alexv01
High Pressure Grounds 737's posted Fri Jan 27 2012 10:33:21 by alaskan9974
ERJ170 Cabin Pressure posted Wed Nov 2 2011 17:36:21 by hstrasbe
Pressure Above Vs Below Wing posted Thu Sep 15 2011 04:44:29 by faro
787 Cabin Pressure posted Fri Sep 9 2011 06:49:57 by Chamonix
Cabin Pressure On Taxi posted Mon Mar 21 2011 09:54:02 by ctempleton3
Trying To Understand Cabin Pressure? posted Mon Jan 10 2011 11:48:11 by readytotaxi
Helios 522 And The B737 Pressure Warning posted Sun Dec 19 2010 20:51:31 by rolfen

Sponsor Message:
Printer friendly format