Go Back  PPRuNe Forums > Flight Deck Forums > Tech Log
Reload this Page >

CRJ900 IRS high drift rate

Wikiposts
Search

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

CRJ900 IRS high drift rate

Thread Tools
 
Search this Thread
 
Old 23rd September 2018 | 09:48
  #1 (permalink)  
Thread Starter
 
Joined: Oct 2009
Posts: 255
Likes: 3
From: Close to you
CRJ900 IRS high drift rate

Hi

we are experiencing problems on both IRS units on one particular aircraft individual in our fleet.
aircraft is around 2 years old and the IRS is drifting between 4-8NM per hour flying north/south I in the northern hemisphere.
last days we have started our journeys from around N54, and needed to do full alignment on the turnarounds due to IRS FMS disagree.

any takes on this?
what baffles me is that both IRS drift quite a lot.
imminent failure approaching?
dcoded is offline  
Reply
Old 23rd September 2018 | 16:30
  #2 (permalink)  
15 Anniversary
 
Joined: Jun 2007
Posts: 54
Likes: 3
From: Montreal, Canada
Originally Posted by dcoded
Hi

we are experiencing problems on both IRS units on one particular aircraft individual in our fleet.
aircraft is around 2 years old and the IRS is drifting between 4-8NM per hour flying north/south I in the northern hemisphere.
last days we have started our journeys from around N54, and needed to do full alignment on the turnarounds due to IRS FMS disagree.

any takes on this?
what baffles me is that both IRS drift quite a lot.
imminent failure approaching?

wayyyyy too much drift for a 2 years old airplane. The RC FMS 4200 or the 6000 series will usually post an FMS-IRS disagree when you have 2.5 nm of drift in the first 30 mins of flight, and there after, if the drift is more than 2.5nm per hour of flight...those are typical numbers.
vickers vanguard is offline  
Reply
Old 24th September 2018 | 16:36
  #3 (permalink)  
100 Countries Visited
25 Anniversary
 
Joined: Jul 1999
Posts: 162
Likes: 5
From: Out of a Suitcase
Originally Posted by dcoded
Hi

we are experiencing problems on both IRS units on one particular aircraft individual in our fleet.
aircraft is around 2 years old and the IRS is drifting between 4-8NM per hour flying north/south I in the northern hemisphere.
last days we have started our journeys from around N54, and needed to do full alignment on the turnarounds due to IRS FMS disagree.

any takes on this?
what baffles me is that both IRS drift quite a lot.
imminent failure approaching?
I've experienced a large drift on 1 IRS on a different Type.
An investigation found this IRS had a different part number and shouldn't have been installed in that airframe.

This should be the first thing to check.
Eric Janson is offline  
Reply

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



Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2026 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.