When GPS going down is no longer a theory

BobDDuck

Island Bus Driver
I think our lack of curiosity is a crying shame. Pilots should be incredibly curious. Knowing "why" is often more important than simply knowing "how" in the airplane.
Knowing why is fine... as long as the information is provided from a reputable source.

Being curious and trying to figure it out leads to an uneven application of knowledge and some pilots getting themselves in trouble. We had a plane shut down HND for a few hours once because they got curious about a hydraulic system.
 

ppragman

FLIPY FLAPS!
Knowing why is fine... as long as the information is provided from a reputable source.

Being curious and trying to figure it out leads to an uneven application of knowledge and some pilots getting themselves in trouble. We had a plane shut down HND for a few hours once because they got curious about a hydraulic system.
Well don't experiment, but that doesn't mean curiosity is bad. In fact quite the contrary. Talk to maintenance, call the manufacturer, learn the systems!

If you're dumb enough to try unapproved procedures out of sheer boredom that's a very different problem than being curious.
 

Autothrust Blue

"...I know bait when I see it..."
I think our lack of curiosity is a crying shame. Pilots should be incredibly curious. Knowing "why" is often more important than simply knowing "how" in the airplane.
I’ve seen it in abundance. My punishment for having eyes and knowing what they are for runs something like this:

“Hey, what’s with that speed tape remark on the release?”
“Dunno brüh, good airplane.”
MX Control: “uhhh call dispatch”
Dispatch: “uhh call MXC”
MX Control: “uhhh”
 

OldGuy1

Active Member
Sorry, been trying very hard to get it, ... but just. cannot. understand. ... ??? ... Please tell me I'm missing something. Even with the ARCDUs out, we still have a tune-able spare VOR receiver (3 required for Cat III at my shop) ... and that's all we ever had in the 80's. Can still navigate the whole continent with just one of those, right? Fly all kinds of approaches with LOC/ VOR, maybe NDB in Canada. WX is usually not at mins. everywhere at the same time ... FMS and GPS just sort of a nice toy, but not really essential to aviation ... ??? What am I missing???
 

BobDDuck

Island Bus Driver
What am I missing???
On some aircraft this glitch also took out the transponder. Need one of those to operate in most of the airspace jets fly in. It also took out the ADSB-out functionality, which also caused airspace restrictions.

On the CRJs, DME/DME position resolution isn't accurate enough for the higher end rnav procedures (including a lot of sids and stars) so that precludes a large number of operations.
 

Alchemy

Partner, Ally, Friend
MEL stuff aside, can the INS/INU not operate independently of GPS with whatever acceptable drift component it would have, like INSs used to do before GPS ever existed? Or will it not work at all without it. That’s what I’m curious about....a technical question.
Ignoring the bombardier products for a moment, apparently this was even grounding MD11s, 767s and 747-4s with the affected Rockwell-Collins Multi-mode receiver. Of course those airplanes have a full IRS with triple IRUs (ADIRUs in the 747-8's case at least). Exactly why they were grounded, I'm not certain, but I can speculate:

On the 747 at least (both -400 and -8), deferring both GPS's is allowed. The Collins Multi-Mode Receiver is apparently completely failing due to the GPS error, it is crapping the bed and becoming completely inoperative. Some MMR's (from what I'm reading) can be responsible for (in addition to GPS reception), ILS and VOR reception. If the MMR totally craps the bed (as the DoD GPS satellite "leap second" update was causing it to do), you are down to uhhhhh DME/DME/IRS, NDB and pilotage/dead reckoning? No-go. I've even read from some sources that DME is tuned through the MMR as well.

I'm guessing that a lot of affected airplanes could've operated with increased ANP/RNP if it were just the GPS's being knocked out by the loss of the MMR, but not with GPS+ILS+VOR being gone. The 747-400 for instance has "3" ILS systems, with at least 1 needing to be operative or the jet is grounded. Also if the left VOR is inop the jet is grounded. It would seem really dumb to have all these radios wired through a single point of failure, but it would also be really dumb to have the loss of a single AOA sensor to cause a jet to become uncontrollable.....
 
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Autothrust Blue

"...I know bait when I see it..."
If you can't manipulate it, you don't need to know it. The only thing build a plane did was make instructors feel good about how smart they are and how dumb trainees are.
This is something that can be manipulated, or at least controlled from the cockpit.
 

jtrain609

I'm a carnal, organic anagram.
This is something that can be manipulated, or at least controlled from the cockpit.
Exactly.

Can I flip a switch to pull cross side data because of erroneous speed indications? Great. We should talk about pitot tubes. Can I change the position of the bypass valve on the precooler for the FCOC? No? Then maybe our time would be better spent elsewhere.
 

thevideographer

Well-Known Member
Exactly.

Can I flip a switch to pull cross side data because of erroneous speed indications? Great. We should talk about pitot tubes. Can I change the position of the bypass valve on the precooler for the FCOC? No? Then maybe our time would be better spent elsewhere.
Are you simultaneously ridiculing people who think pilots should know more systems and showing off your systems knowledge?
 

z987k

Well-Known Member
If you can't manipulate it, you don't need to know it. The only thing build a plane did was make instructors feel good about how smart they are and how dumb trainees are.
I didn't say we should go back to build the airplane.
Given the failures this thread is dedicated to and it seems that almost all the responses are along the lines of shut up and color, no one knows how integrated that system is, and it looks like it could be quite useful information.

I figured quoting roger and the AoA problems of late would help emphasize that point.

And last it's more than passing a check ride. It's intellectual curiosity. It's about learning more than you have to in order to skate by. Continuing to learn far past when the training event is over.
 

Autothrust Blue

"...I know bait when I see it..."
Are you simultaneously ridiculing people who think pilots should know more systems and showing off your systems knowledge?
Three spheres.

Need to know.
Nice to know.
Don’t need to know.

What the controls on the flight deck do is need to know. Some of the higher order systems stuff is nice to know. Things you cannot do anything about? don’t need to know. Especially if you displace anything from the former two categories.

“This engine has a variable geometry compressor.”
“Can I do anything about it?”
“Well, no.”
 
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