View Full Version : Domestic Jets - What Navigation System?
HotPete
30th Mar 2010, 05:17
Whilst long-range jets (like the B747) use Inertial Navigation System (INS), do domestic jets (like B737) use the same? Or GPS?
littlehurcules
30th Mar 2010, 05:22
IRS & GPS
The GPS updates the IRS
blueloo
30th Mar 2010, 05:23
Older 737-400s use IRS (Inertial Reference Systems - which is an updated INS) with ground based updated DME/VOR. They have 2 IRS's. Newer 737-800s also have 2 IRS's with ground based and GPS input for very accurate navigation.
767's use 3 IRS's mainly with ground based updates and a few newer ones with GPS updates.
Not sure on the minibuses.
In this day and age all of the large RPT jets should have the precision from GPS updates - but it costs dollars. With the introduction of ADSB - hopefully GPSs will become mandatory.
Going Boeing
30th Mar 2010, 05:38
HotPete, the other reason that IRS's are used is that they supply the Attitude sources for flight instruments and other systems as well as being a source of navigation data. Most aircraft that are certified for Cat III Low Visibility approaches have three IRS to give the required level of redundancy.
Icarus2001
30th Mar 2010, 07:46
Then there are the "modern" jets like the F100 and B717 that do not have GPS or cannot do RNAV approaches.:eek:
CasperA320
30th Mar 2010, 08:06
Airbus have 3 IRS and updated by VOR/DME[ on old a/c ]
The new a/c also have 2 GPS which know update the IRS
The nav system is very accurate to about the size of a tennis court!
Mach E Avelli
30th Mar 2010, 08:30
You can fit GPS to any aeroplane but the problem with some older types is getting the GPS to interface with the other navigation systems and autopilot.
Icarus the problem is not with the F100, but with the tightass operators not willing to pay for an integrated GPS modification.
Wizofoz
30th Mar 2010, 10:10
Hot Pete-
Recent Long Range aircraft also use IRS updatted by GPS. Most 747-400s have had GPS updatting for 15 years or so, as it is a requirement for FANS navigation.
The 777 has had 2 GPS sources as primary IRS updatting since it's inception.
RENURPP
30th Mar 2010, 10:45
ICARUS,
I was sure the 717 I flew last week had 2 x IRS and GPS.
:confused::confused:
smiling monkey
30th Mar 2010, 10:54
This is how they do it in some of the really old aircraft in some parts of the world ... a Boeing 737-200 with a Garmin 296! LOL!
http://i42.tinypic.com/2rqbo0w.jpg
Seems to work quite well inflight, although I doubt whether it's coupled to the autopilot!
http://i39.tinypic.com/kdq4ib.jpg
Capn Bloggs
30th Mar 2010, 11:21
Looks like a popular GPS...
http://i521.photobucket.com/albums/w334/capnbloggs/RIMG2933copy.jpg
Led Zep
30th Mar 2010, 13:38
That'd be the Globalnaya navigatsionnaya sputnikovaya systema version of the 296, right? :}
Checkout the pictures on the overhead panel.
boofta
30th Mar 2010, 16:23
There not pictures, thats the divine guidance system!
VH-XXX
30th Mar 2010, 21:12
Actually I think in that second pic the photo shows a 196 Garmin!
I was a little surprised on a recent QF flight to see that the old 737 banger we were in didn't have GPS. Not that I care, you'd just think that they all would have it these days, but I guess they survived this long without it :)