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Civilian plane crash in New Mexico tied to military GPS blocking

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Re: Civilian plane crash in New Mexico tied to military GPS blocking

#221

Post by xnx »

idlewords wrote: post #188
mrngld wrote: post #15

When I used to fly in Florida in the 2005-2015ish timeframe, NOTAMs for GPS interference (it didn't say that exactly but that's what it meant) were an everyday occurrence along my path, it became boilerplate. I experienced it a few times. One moment the GPS thinks you're plodding along next to Ocala, next moment it thinks I've teleported a thousand miles away, and then it'd just quit. But that's what we train for. Th…

The highest mountain summit in Florida is 105 meters above sea level.

And even that is basically Alabama.

Re: Civilian plane crash in New Mexico tied to military GPS blocking

#222

Post by sokoloff »

scott00 wrote: post #207
inoffensivename wrote: post #84

Airline captain here... A visual approach to an airport in mountainous terrain on a moonless night is very risky. In our operation, departing to an airport with missing weather reports would not be permitted, so in a Part 121 scheduled service this flight may not have been able to dispatch legally. Airliners have DME/DME triangulation which allows them to achieve area navigation (RNAV) without GPS. The interference w…

Would using the ILS without the local altimeter actually be a safe way to land the plane? (Ignoring whether or not ATC is allowed to give you clearance for that.) Is the requirement of a local altimeter just overly cautious?

It would be safe. The ILS projects a localizer signal (left/right deviation compared to runway alignment) and glideslope signal (up/down deviation versus the intended flight path, usually about 3°).

The only thing you need a precision altimeter setting for is to determine the safe decision altitude (point at which you need to see the runway environment to continue, else initiate a missed approach) and a fairly theoretical chance to intercept a false glideslope lobe.

With the clear weather, knowing the decision altitude with precision was not important and the false glideslope is easy to identify by comparing outside view and descent rate needed to stay on the glideslope.

Re: Civilian plane crash in New Mexico tied to military GPS blocking

#223

Post by michaelt »

lbriner wrote: post #47
K0balt wrote: post #17

GPS is not essential to air navigation. It’s nice to have, and there are some approaches that legally require it to be operational in order to fly them (IFR procedures) but aviation has other systems in place to guide aircraft under conditions where visual flight navigation is impossible. In this case, IMHO, the pilots had become complacent and lax in their navigational rigor because of the fact that GPS makes a lot…

This was the partial cause of Air France 447. Pilots were so used to "the plane won't make a mistake" that they were not aware/not trained properly about things that are nothing to do with the FMS like frozen pitot tubes and also that the autopilot has a number of "modes" which mean you need to go back to basics like altitude, attitude and air speed.

> Pilots were so used to "the plane won't make a mistake" that they were not aware

Of course there have also been crashes where pilots wrongly dismissed sensor data.

In the Kegworth air disaster [1] the pilots had sensor data telling them the left-hand engine was at fault - but a previous model of the plane had a reputation for unreliability in that sensor, and the pilots shut down the right-hand engine on the basis of other evidence.

So we don't want pilots blindly trusting broken sensors - but we also don't want them to dismiss working sensors as broken.

[1] https://www.faa.gov/lessons_learned/transport_airplane/accid...

Re: Civilian plane crash in New Mexico tied to military GPS blocking

#224

Post by collabs »

I don't know how to phrase it in military lingo but based on what I've read here on this thread, the military must stop these tests.

1. Use self contained "unit tests" or "dry runs" if you will for day to day scheduled or training purposes

2. Do precise (far fewer) "end to end" tests only where justified like for new hardware certification, never for shits and giggles

Re: Civilian plane crash in New Mexico tied to military GPS blocking

#225

Post by wombatpm »

rdtsc wrote: post #55
ceejayoz wrote: post #48

Earlier quoted context omitted.

HN threads on aviation are always a bit goofy to anyone who's actually flown a plane, yeah.

I never flew a plane just know enough that a visual approach means “visual” rules. Hitting a mountain at that point is hard to argue for blaming anyone else but the pilot error? Did I get it right?

Night flying, mountain terrain, little moonlight. Pilots focused on distant landing point and hit intervening ground on descent.

A crash is usually the end result of several previous bad decisions.

Re: Civilian plane crash in New Mexico tied to military GPS blocking

#226

Post by 2PqboPPmKegvanx »

rob74 wrote: post #125

Unfortunately I can't access the article, but this video by Juan Browne (IMHO one of the most knowledgeable and no-nonsense aviation YouTubers) also provides a very good summary: https://www.youtube.com/watch?v=Dcyup4xVQuM What I found shocking is that there are so few road ambulances in that region that medevac flights are routinely ordered for transporting patients to keep ambulances available in case there is a ro…

Neither here nor there but that whole upper NE corner of the state only has a handful of hospitals - in part because there just aren't that many people who live there.

NMLEG map of counties and population | https://www.nmlegis.gov/publications/handbook/counties.pdf

wiki 2020 census map | https://upload.wikimedia.org/wikipedia/commons/a/a2/New_Mexi...

Re: Civilian plane crash in New Mexico tied to military GPS blocking

#227

Post by alistairSH »

cdot2 wrote: post #210
alistairSH wrote: post #200

Earlier quoted context omitted.

You're not wrong, but that doesn't necessarily mean Uncle Sam should be dicking around with GPS jammers as a normal thing (at least not without acknowledging that doing so changes the risk profile of aviation to some extent).

" acknowledging that doing so changes the risk profile of aviation to some extent" Isn't that what the NOTAM is?

Clearly the NOTAMs aren't doing the job, as this isn't the only instance of issues. It's just the only instance of a crash with fatalities.

Re: Civilian plane crash in New Mexico tied to military GPS blocking

#228

Post by PhaedrusV »

jjwiseman wrote: post #179

I run GPSJAM.org, have been studying and tracking the effects of GPS interference on aviation for the past 5 years, and I was a source for this article. I'm not a pilot and I don't work for any aviation agency. I'm very curious to see what the final NTSB report says, but their preliminary report along with commentary from other analysts seems to show that this was a crew that made bad choices and died because of it.…

The problem here is the assumption that if the US mil weren’t jamming GPS it wouldn’t be getting jammed. GPS is trivially easy to jam for any state actor, and it’s not “macho” to say that pilots always need to be able to safely conduct flights in its absence.

Re: Civilian plane crash in New Mexico tied to military GPS blocking

#230

Post by kunai »

scott00 wrote: post #207
inoffensivename wrote: post #84

Airline captain here... A visual approach to an airport in mountainous terrain on a moonless night is very risky. In our operation, departing to an airport with missing weather reports would not be permitted, so in a Part 121 scheduled service this flight may not have been able to dispatch legally. Airliners have DME/DME triangulation which allows them to achieve area navigation (RNAV) without GPS. The interference w…

Would using the ILS without the local altimeter actually be a safe way to land the plane? (Ignoring whether or not ATC is allowed to give you clearance for that.) Is the requirement of a local altimeter just overly cautious?

ILS, yes (the G/S vector and angle is calibrated to account for terrain), LOC on the other hand (i.e. non-precision with no G/S information) would have probably ended up in the same situation as it requires pilots to manually manage rate of descent. Not all runways have ILS equipment on both sides of the runway, let alone on all runways available or one that is active. At some airports it's possible you only run a 30% chance or lower that you can actually use the ILS to land, because the one with the equipment may not be the active one (and which runway is active changes depending upon wind and weather)
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