Stoicescu
Topic Author
Posts: 79
Joined: Sun Sep 11, 2005 2:39 pm

IRU Question

Wed Sep 14, 2005 11:28 am

Let's assume the following scenario:

You move the IRS switches to Nav and during the 10 minutes (more or less depending of aircraft) the aircraft gets moved because of some reason...You get IRS failed! How far back do you have to go with the IRU setup to restart it? (do you just move it to off and than to Nav again or you have to enter your position again also)

What is your company SOP saying about the economy setting in the FMS. It is said 80 is the standard option to use however I guess because of the current fuel prices some companies will go for lower numbers.

All my respect,
Stoicescu
 
nonfirm
Posts: 426
Joined: Mon Sep 12, 2005 3:04 pm

RE: IRU Question

Wed Sep 14, 2005 1:02 pm

I HAVE SEEN SEVERAL IRU FAILURES AND WE HAVE SWITCHED THEM OFF AND BACK ON AND ALL WENT WELL.NORMALLY GET THIS AS A RESULT OF THE TOW FROM GATE TO GATE.
 
DeltaGuy
Posts: 3965
Joined: Wed Sep 12, 2001 5:25 am

RE: IRU Question

Wed Sep 14, 2005 1:31 pm

Back in the day, I saw 100, and even 300 one time when the FO needed to get home quickly. High cost indexes compared to now.

DeltaGuy
"The cockpit, what is it?" "It's the little room in the front of the plane where the pilot sits, but that's not importan
 
PhilSquares
Posts: 3371
Joined: Sun Mar 28, 2004 6:06 pm

RE: IRU Question

Wed Sep 14, 2005 4:13 pm

If the aircraft is moved while tha IRU are aligning, on the 744 they have to be recycled to off and then to nav. The PPOS has to be inserted. The route might or might not stay in there.

At my airline we use 130 on the cost index. If the flight is late then we can go up to 250.
Fly fast, live slow
 
avioniker
Posts: 1099
Joined: Tue Jan 01, 2002 5:38 am

RE: IRU Question

Wed Sep 14, 2005 9:34 pm

That's one of the nice features of the ADIRU's installed in the 737NG fleet. The software has been programmed to simply stop the alignment until the aircraft is still again and it picks up where it left off. It's also very tolerant of position errors so moving the aircraft across the field probably won't cause a position crash.
That's a bit simplified but that's how it works.
Ah software...
 Smile
One may educate the ignorance from the unknowing but stupid is forever. Boswell; ca: 1533
 
PW2040
Posts: 58
Joined: Thu Nov 04, 2004 1:40 am

RE: IRU Question

Sat Sep 17, 2005 11:00 pm

Hi Guys.

On the B767-200 in my company we use 65 as a standard which approx. gives around .80 and on the B757 we used 40 ( .80 ) as standard.

Greetings,
PW2040

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