Is it time to forgo VHF navigation?

[rocketman1988]

"... IRS/INS is the last backup source, after VOR and DME..."

Might want to tell Boeing that, because that is NOT what they are training...

Also, in my previous aircraft (757/767), there were no GPS receivers...and the VOR/DME was used to update the IRS...

Again, when you are 2000 miles out over the ocean, there are NO VOR/DME stations...

[SPX]

Originally Posted by rocketman1988

Might want to tell Boeing that, because that is NOT what they are training...

I have sent a PM to rocketman1988 to get further information on this. I have committed to work with Boeing training to get the issue worked out.

[Thermos]

Originally Posted by DCBrown198

Is it time to forgo VHF navigation?

Not for me...

https://www.gps.gov/governance/advis...-06/martin.pdf

https://www.gps.gov/multimedia/prese...IS/kolasky.pdf

https://www.gps.gov/cgsic/meetings/2018/lawrence.pdf

...but only you can decide how much you?ll be impacted if there?s a GPS outage in your operating area. Take a look at the last briefing to see what the FAA intends to provide as a backup to GPS nav.

Dave

[rongawer]

Originally Posted by DCBrown198

Anyone else been pondering this?

David

Pondered and decided to not install a NAV unit. I haven't looked back or missed it in over 300 approaches since.

[Jpm757]

Bob,
Originally (before GPS) the Boeing birds (757,767) had triple IRS units that were updated by Vor/Dme signals, over water they went into IRS nav only mode, once back over land they updated. Most of these have been upgraded to the Pegasus flat panel displays utilizing dual GPS receivers.

[rocketman1988]

If you are replying to me, yes I know. I flew the 757/767 for 16 years through the pegasus upgrade...

[RV6_flyer]

I like the idea of having the VHF Nav receiver in the airplane even if I do not use it for much navigation.

There have been a number of airports that have the AWOS, ASOS, or ATIS transmitting over a VOR frequency. There also is the possibility of communication with Flight Service by receiving over the VOR frequency.

The communication signals that I can receive over the VHF / VOR Nav receiver makes the added cost, weight, and panel space worth it to me.

Being able to use if for an ILS is just a plus.

I have been using ADS-B in for about 6-years. Yes I have ADS-B out as of May 2019 but have not used the ADS-B IN Wx enough to feel safe without hearing it on VHF.

Unfortunately my certified GPS approach receiver requires a VHF nav receiver. Yes it is an older unit dating back over 15-years. I have a VHF nav receiver in my RV-6 and would like to have one in the RV-8 project but when it becomes time to part with money, I may end up not having one.

[unitink72]

Originally Posted by woxofswa

The primary source is Inertial navigation. GPS serves, along with old school NAV, as a cross checker, verifier, position tweaker to the primary INS/IRS/IRU?s.

Losing Inertial NAV in a Boeing is a big deal. Losing GPS is a nuisance light and a yawn.

There will be a difference between fly by wire aircraft and the older ones. I think the 787 was the first. IRS is extremely important to the "inner loop" control laws. I can't speak for the "outer loop" navigation/autopilot laws though.

We are well along in the process to have the 777X fly by wire certified. Wish that bird would fly already!

[gmcjetpilot]

Originally Posted by rocketman1988

"...Might want to tell Boeing that, because that is NOT what they are training...

Also, in my previous aircraft (757/767), there were no GPS receivers...and the VOR/DME was used to update the IRS...

Again, when you are 2000 miles out over the ocean, there are NO VOR/DME stations...

Bob. The 757767 came out in the early 80s and there was no GPS. Most have been upgraded with dual GPS.

You're correct out over the ocean IRU was all you had and HF radio for voice position reports. (Use to be INS inertial nav system, but IRU's are not only nav they drive flight instruments.) However to fly North Atlatic today you are required to have "navigation precision", "surveillance and communication precision", part of Future Air Navigation System (FANS). You need GPS as well as digital satellite communication. Clearance comes direct to your CDU/FMS. You use the HF radio only to make initial contact with Gander or Shanwick as a backup, and that's it. The vertical and in trail separation across the Atlantic has been reduced which requires very high level of nav, surveillance and commuication. There may be no radar or ground base navigation over the water, but the game has completely changed in the last 10-15 years, much less since early 80's. GPS is part of FANS....

You might recall before GPS flying Atlantic seeing your 757/767 nav display jump as you got close to land again and FMS started updating on DME and VOR. IRU is accurate but after a few hours it will have error. GPS is more accurate indefinitely.

[sailvi767]

Originally Posted by rocketman1988

"... IRS/INS is the last backup source, after VOR and DME..."

Might want to tell Boeing that, because that is NOT what they are training...

Also, in my previous aircraft (757/767), there were no GPS receivers...and the VOR/DME was used to update the IRS...

Again, when you are 2000 miles out over the ocean, there are NO VOR/DME stations...

To allow RVSM and reduced track separations there have been changes. In the original 757/767 configuration the aircraft never used VOR?s. It navigated off DME/DME and downgraded to IRS Nav if two valid DME signals could not be received. This caused the infamous 30 AOB wake up turns at two in the morning when the aircraft grabbed two DME?s at track exit and the magenta line moved 1 or two miles instantly. This could put the aircraft into buffet. They added a algorithm to smooth that out but the aircraft did not blend position sources. It was one or the other. With the retrofit of GPS they are 100% GPS for actual position however the GPS position is used to update the IRS?s. If you have a GPS loss the IRS?s should be right on. Different airlines and boxes may have different solutions.