GPS jamming becoming a real problem
#31
Gets Weekends Off
Joined APC: Feb 2006
Position: B-737NG preferably in first class with a glass of champagne and caviar
Posts: 5,886
Operated across the Pacific with IRS’s. Average leg was 10 hours plus. Required to log velocities and distance errors 10 minutes after the parking brake was set. Trying to remember the greatest distance error was about 2 miles. That said No biggy, unless you need to accomplish a LPV approach.
#33
Operated across the Pacific with IRS’s. Average leg was 10 hours plus. Required to log velocities and distance errors 10 minutes after the parking brake was set. Trying to remember the greatest distance error was about 2 miles. That said No biggy, unless you need to accomplish a LPV approach.
And now we have tighter airspace and stricter required navigational performance requirements.
#34
Banned
Joined APC: Oct 2008
Position: Window Seat
Posts: 1,430
Good idea.... but since I already do that do you mind telling the Syrians and Russians to stop jamming the GPS on the Turkey/Iraq border as well? Smartass.
It might raise relatively rapidly immediately following GPS loss, but it should quickly settle down at a reasonable (for non-GPS RNAV) value.
If you're oceanic, on INS only, then ANP should very gradually increase over time without GPS. Same for a hypothetical total jamming of all sat and ground based nav over land.
If you're oceanic, on INS only, then ANP should very gradually increase over time without GPS. Same for a hypothetical total jamming of all sat and ground based nav over land.
Yeah, but this isn't 1998, some of the ways ANP is being calculated and implemented (as well as the software) have changed since then. I sure how you wouldn't consider ANP values in the 3-4 range as acceptable for any kind of RNAV based approach in 2019.
#35
Disinterested Third Party
Joined APC: Jun 2012
Posts: 5,925
Ah, an intellectual.
You tell them. It's a combat zone. Go figure.
If you're already flying better equipment, then it's not really an issue, is it?
If you're already flying better equipment, then it's not really an issue, is it?
#36
Gets Weekends Off
Joined APC: Dec 2005
Posts: 8,883
It's a bit like not verifying the fuel upload. I see most look at the fuel indication and if it matches what's wanted, the crew is happy. It seems to be a lost basic that one should look at the previous ending fuel, fuel upload, add them and note any discrepancy that isn't explained by APU burn, etc. Simply things, but important, and should be done every time.
Before the merger, our own airline delivered fuel slips that showed previous arrival fuel and gallons added and I would do that math just like you said to verify it. It was actually part of the our procedures. Not anymore. I don't see how that can be done now, we just don't get that info anymore. SOPs call to 'only' verify the FOB on the screen.
As for jamming issues: while there may come a time when ground based navaids or gone, that time is not today. I've never been an advocate of an all-eggs-in-one-basket approach, and am not today. There are locations, of course, that rely only on RNAV and GPS for approaches, arrivals, departures, etc, but when operating IFR to such locations, good airmanship dictates having options that do use ground based navaids, including alternates in mind. It's been mentioned that these concerns are chiefly for general aviation aircraft. Again, good airmanship dictates having a plan B.
It's possible to paint one's self into a box. Don't do that.
I also fly general aviation, sometimes in aircraft with no nav systems; it's either charts or a handheld GPS (and charts); with loss of GPS, then it's pilotage and dead reckoning.
The latter two still work. If one insists on going IFR, and has only RNAV capability, then we're back to good airmanship, which means having a plan to get to VMC and to fly visually.
It's possible to paint one's self into a box. Don't do that.
I also fly general aviation, sometimes in aircraft with no nav systems; it's either charts or a handheld GPS (and charts); with loss of GPS, then it's pilotage and dead reckoning.
The latter two still work. If one insists on going IFR, and has only RNAV capability, then we're back to good airmanship, which means having a plan to get to VMC and to fly visually.
#37
Gets Weekends Off
Joined APC: Feb 2006
Position: C47 PIC/747-400 SIC
Posts: 2,100
There is absolutely no justification for initializing the IRU without verifying current position. Doing otherwise is poor airmanship.
One should verify what the former residual IRU performance was, if available, before bringing the system up, however, to get an idea of which unit might be the most efficient in the event of a fail down and a need to rely on one without other nav input. Again, just good airmanship to now which unit shows the strongest and most accurate, before starting the flight. I very seldom see anybody do this.
It's a bit like not verifying the fuel upload. I see most look at the fuel indication and if it matches what's wanted, the crew is happy. It seems to be a lost basic that one should look at the previous ending fuel, fuel upload, add them and note any discrepancy that isn't explained by APU burn, etc. Simply things, but important, and should be done every time.
As for jamming issues: while there may come a time when ground based navaids or gone, that time is not today. I've never been an advocate of an all-eggs-in-one-basket approach, and am not today. There are locations, of course, that rely only on RNAV and GPS for approaches, arrivals, departures, etc, but when operating IFR to such locations, good airmanship dictates having options that do use ground based navaids, including alternates in mind. It's been mentioned that these concerns are chiefly for general aviation aircraft. Again, good airmanship dictates having a plan B.
It's possible to paint one's self into a box. Don't do that.
I also fly general aviation, sometimes in aircraft with no nav systems; it's either charts or a handheld GPS (and charts); with loss of GPS, then it's pilotage and dead reckoning.
The latter two still work. If one insists on going IFR, and has only RNAV capability, then we're back to good airmanship, which means having a plan to get to VMC and to fly visually.
One should verify what the former residual IRU performance was, if available, before bringing the system up, however, to get an idea of which unit might be the most efficient in the event of a fail down and a need to rely on one without other nav input. Again, just good airmanship to now which unit shows the strongest and most accurate, before starting the flight. I very seldom see anybody do this.
It's a bit like not verifying the fuel upload. I see most look at the fuel indication and if it matches what's wanted, the crew is happy. It seems to be a lost basic that one should look at the previous ending fuel, fuel upload, add them and note any discrepancy that isn't explained by APU burn, etc. Simply things, but important, and should be done every time.
As for jamming issues: while there may come a time when ground based navaids or gone, that time is not today. I've never been an advocate of an all-eggs-in-one-basket approach, and am not today. There are locations, of course, that rely only on RNAV and GPS for approaches, arrivals, departures, etc, but when operating IFR to such locations, good airmanship dictates having options that do use ground based navaids, including alternates in mind. It's been mentioned that these concerns are chiefly for general aviation aircraft. Again, good airmanship dictates having a plan B.
It's possible to paint one's self into a box. Don't do that.
I also fly general aviation, sometimes in aircraft with no nav systems; it's either charts or a handheld GPS (and charts); with loss of GPS, then it's pilotage and dead reckoning.
The latter two still work. If one insists on going IFR, and has only RNAV capability, then we're back to good airmanship, which means having a plan to get to VMC and to fly visually.
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