GPS Missed Approach With No GPS?

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Anthony8822

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Anthony
The other day I was out keeping current shooting an RNAV into the local airport, when, inside the FAF, I lost the GPS. Thankfully I was in clear weather, so I had no REAL issue, but what if I hadn't been? With the missed approaches on GPS approaches being - well - GPS fixes - what would you do if the GPS dropped out? My gut reaction was to head to the VOR and fly the published hold for the VOR approach into the same airport, and of course to call ATC had it been for real.

I haven't done much instrument flying in the past year so my apologies if there's some big obvious answer to this that I'm missing.
 
At our airport there is an ILS on 16R so if I were on the GPS to 16L/R I'd probably fly the ILS missed. I alway have the local VOR and Localizer in my Nav 2/standby.
 
If there's an obvious answer, it's, you have an equipment failure, you make do with what you have.

If what you describe happened in the clouds, the very last thing on my mind would be what the FAA wants me to do. I want to go missed and not hit something. Sure, if there were another approach that fit and my hands weren't full (figuratively and literally speaking), I might make the switch. (I'll leave out the iPad for this answer in case the failure was GPS and not my receiver)

OTOH, your comment, "of course call ATC" tells me there's no communications failure which, especially in a radar environment, makes it extra easy. You have an approach plate with a missed that begins with either a straight ahead or climbing turn, right? Do it. Call ATC, Let them know. They'll give you alternate instructions.
 
DesertNomad said:
At our airport there is an ILS on 16R so if I were on the GPS to 16L/R I'd probably fly the ILS missed. I alway have the local VOR and Localizer in my Nav 2/standby.
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I agree - but I forgot to mention that other than a radar vectored/DME VOR-A, this is the only approach to that runway.
 
There was a thread on this not long ago.

I've had a GPS lose signal in the clouds during a missed approach. Worse, it was below radio coverage from Approach at a nontowered airport, so no vectors. What I did was climb out at runway heading until I could get in contact with Approach. This is consistent with the missed approach procedure, but without the positive guidance. As I got high enough for radio contact, the GPS came back.

It all depends on the conditions. You have to wing this, so to speak. Avoid obstructions and terrain while you climb, and get a vector as soon as you can.

The approach in question was KHAF RNAV Z 30. http://155.178.201.160/d-tpp/1703/06675RZ30.PDF
 
MAKG1 said:
There was a thread on this not long ago.

I've had a GPS lose signal in the clouds during a missed approach. Worse, it was below radio coverage from Approach at a nontowered airport, so no vectors. What I did was climb out at runway heading until I could get in contact with Approach. This is consistent with the missed approach procedure, but without the positive guidance. As I got high enough for radio contact, the GPS came back.

It all depends on the conditions. You have to wing this, so to speak. Avoid obstructions and terrain while you climb, and get a vector as soon as you can.

The approach in question was KHAF RNAV Z 30. http://155.178.201.160/d-tpp/1703/06675RZ30.PDF
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Yep. Given the straight ahead climb for about 5500' over the water, sounds like a good bet to me.
 
A potential problem like this reinforces that we need to be situationally aware. If you flew a missed without guidance at some airports, you could run into something! I guess the best solution would be to fly the missed as best you could without the GPS. How common is it to lose GPS signal after the FAF (I don't have GPS)?
 
somorris said:
A potential problem like this reinforces that we need to be situationally aware. If you flew a missed without guidance at some airports, you could run into something! I guess the best solution would be to fly the missed as best you could without the GPS. How common is it to lose GPS signal after the FAF (I don't have GPS)?
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I don't have any stats on it, but the MAP is where you are most vulnerable to interference from local ground sources, if for no other reason than that's where you're closest to the ground.

In my case, there was a well known surfing competition going on underneath those clouds, which implies an unusually large number of people and vehicles underneath the final approach segment. And there is a small but crowded highway right next to the airport.
 
somorris said:
A potential problem like this reinforces that we need to be situationally aware. If you flew a missed without guidance at some airports, you could run into something! I guess the best solution would be to fly the missed as best you could without the GPS. How common is it to lose GPS signal after the FAF (I don't have GPS)?
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Well, its happened to me twice inside the FAF and more than a few times between the IAF and the FAF - but only once under real world conditions and it was an overlay. I switched to a localizer and started the descent, and before I could tell ATC I broke out (only had about a 2000ft ceiling to get down through) and canceled IFR.
 
MAKG1 said:
There are very few approaches around where you're above the MSA during the final approach segment.
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What does being above MSA while shooting approach have to do with what would I do if I lose NAV while shooting an approach?

MSA is specifically for an altitude that you can climb to/be at when the proverbial hits the fan.
 
jaybee said:
What does being above MSA while shooting approach have to do with what would I do if I lose NAV while shooting an approach?

MSA is specifically for an altitude that you can climb to/be at when the proverbial hits the fan.
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How do you propose using the MSA? Would anyone in their right mind want to remain at low altitude with no positive guidance, MSA or not?

The MSA doesn't help you much unless you're already above it. So, you're 1000 feet below the MSA and the GPS blows a fuse. That means there is something you might hit at your altitude, so you need to climb. Which direction? Choose the wrong one and you make a very small smoking hole.

You can't possibly shoot an approach and remain above the MSA at all times. That's like saying you land at 1000 AGL. Approach obstacle clearances are closer than MSA obstacle clearances.
 
I don't know where you get this idea that I want to stay above MSA while shooting an approach. Without getting into some kind of internet ****ing match, you seem to always want to add stuff into discussions that wasn't there or change the terms of the discussion. I don't know if its a reading comprehension problem or you just have "off days" a lot or what...

The original poster asked what do I do if I lose NAV since I need to have NAV for the missed approach. In the scenario given he was on approach, inside the FAF so we can safely assume he was currently in the protected area that the course provides and had the wind correction to stay on that course. So he loses NAV, the appropriate response would be to climb to MSA on course, as that is exactly what it is there for. The only variables in this situation is what is the MSA predicated on, which on an RNAV is most likely a RNAV waypoint. Since he's inside the waypoint it is pretty safe to assume without looking the plate that he is within a couple of miles, probably 5, of that waypoint and presumably at 90 knots in a bugsmasher he will stay within that normally sized 25 nm circle, that we call an MSA, for roughly at least 13 minutes which is plenty of time to make radio calls and sort things out, change navigation source, get vectors, etc, etc, Shoot for that matter even in an RJ at 200 knots you got roughly 5 minutes to get it together.

So while you might not know exactly where you are when you lose your NAV, you should know roughly where you were - past the FAF and before the runway and you can reasonably SWAG that a climb to the MSA will keep you safe for long enough to figure out what to do next.

I mean really this is all pretty basic instrument flying. I guess if no one ever explained to you how to use the MSA you might not be able to connect the dots but really the term Minimum Safe Altitude itself is pretty self explanatory... in absence of any other directions climb to MSA.
 
jaybee said:
I don't know where you get this idea that I want to stay above MSA while shooting an approach. Without getting into some kind of internet ****ing match, you seem to always want to add stuff into discussions that wasn't there or change the terms of the discussion. I don't know if its a reading comprehension problem or you just have "off days" a lot or what...

The original poster asked what do I do if I lose NAV since I need to have NAV for the missed approach. In the scenario given he was on approach, inside the FAF so we can safely assume he was currently in the protected area that the course provides and had the wind correction to stay on that course. So he loses NAV, the appropriate response would be to climb to MSA on course, as that is exactly what it is there for. The only variables in this situation is what is the MSA predicated on, which on an RNAV is most likely a RNAV waypoint. Since he's inside the waypoint it is pretty safe to assume without looking the plate that he is within a couple of miles, probably 5, of that waypoint and presumably at 90 knots in a bugsmasher he will stay within that normally sized 25 nm circle, that we call an MSA, for roughly at least 13 minutes which is plenty of time to make radio calls and sort things out, change navigation source, get vectors, etc, etc, Shoot for that matter even in an RJ at 200 knots you got roughly 5 minutes to get it together.

So while you might not know exactly where you are when you lose your NAV, you should know roughly where you were - past the FAF and before the runway and you can reasonably SWAG that a climb to the MSA will keep you safe for long enough to figure out what to do next.

I mean really this is all pretty basic instrument flying. I guess if no one ever explained to you how to use the MSA you might not be able to connect the dots but really the term Minimum Safe Altitude itself is pretty self explanatory... in absence of any other directions climb to MSA.
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No, it's just that what you're saying is really, really obvious, MSA or not.

You're saying to climb. No kidding. I thought I'd descend.

Except that climbing on course is sometimes the WRONG thing to do. Check out KTVL GPS 18, for instance. Fly straight out, and you WILL collide with terrain. The correct direction requires RNAV, which you don't have. The best you can do is guess a direction over the lake (i.e., a 180 right turn) and try to reestablish comms with Center, or else switch instantly to the lower LDA approach (but, you can be below the minimum for both of them, as the RNAV has the lowest straight ins). You need to make the turn right away in this case. Being late means sniffing granite. The MSA is a mile over your head. You will not get there before you make a smoking hole in wilderness.

There is no one rule, except perhaps for the obvious one that the ground is not over your head. You must know what's going on, and the MSA is not very useful in practice.
 
You're going to be surprised how many people argue you're not supposed to climb if you decide to miss the approach.
 
flyingron said:
You're going to be surprised how many people argue you're not supposed to climb if you decide to miss the approach.
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He seemed to be one of them:

John777 said:
Lastly, If I do not see the one of the visual reference for the runway, can I start climbing even before reaching MAP?
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MAKG1 said:
The last question has a much more straightforward answer. Do not start the missed approach before the MAP. You'll turn earlier, and there may be terrain or obstructions. On some VOR approaches, you can tootle along at the MDA for miles.
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dmspilot said:
He seemed to be one of them:
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Context.... it really matters.

This is not flying a missed approach. It's making up your own because your only usable nav instrument just went TU and you CAN'T fly the missed approach.

Turning early on a missed approach is a bad idea in the general case, as it can turn you directly into terrain or obstructions. If you don't know where "early" or "late" is, it may be your best option. Particularly if you're flying into a valley like the area around KTVL.
 
We didn't say squat about turning. We said CLIMBING. I've had people tell me that I can't start the climb until I hit the missed approach point, which is silly. If I'm off the published approach (either because I've lost the radio or the needle pegged), you darn right the first thing I'm going to do is start the climb.
 
flyingron said:
We didn't say squat about turning. We said CLIMBING. I've had people tell me that I can't start the climb until I hit the missed approach point, which is silly. If I'm off the published approach (either because I've lost the radio or the needle pegged), you darn right the first thing I'm going to do is start the climb.
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There are some situations where you can't climb early, either. Not common, but some approaches have maximum altitudes, usually due to another approach overhead. Examples are all of the eastbound approaches at KOAK, where you are not allowed to exceed a maximum altitude on the final approach and missed approach segments due to overhead approaches into KSFO.

You have to know the approach you're flying.
 
In the KOAK approaches, the missed approach procedures actually has the restrictions on the climb in them.
 
flyingron said:
In the KOAK approaches, the missed approach procedures actually has the restrictions on the climb in them.
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They also have hard altitudes at the FAFs. On some of the approaches, if you were to go missed immediately after the FAF, you would have to descend 200 feet.
 
For starters climb, that should be the first part of just about any missed procedure and one you don't need the GPS for, that will keep you from hitting ****. Then if it doesn't have a heading to fly after getting to the altitude, which it probably does, ask ATC for vectors once you tell them the situation, and if all else fails, 7600 and and the good ole VOR should get you out of trouble.
 
I like finding odd approaches that'll really fry your bacon if you don't pay attention. (I don't go out of my way to go fly them, though.)

KGUC's GPS-B looks rather entertaining.

There's some segments on that one where your better not get lost if the GPS quits before the FAF.

Or you might meet cumulogranite in person.
 
denverpilot said:
I like finding odd approaches that'll really fry your bacon if you don't pay attention. (I don't go out of my way to go fly them, though.)

KGUC's GPS-B looks rather entertaining.

There's some segments on that one where your better not get lost if the GPS quits before the FAF.

Or you might meet cumulogranite in person.
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Yeah, but if you're anywhere on that approach above minimums, you can fly direct to the missed approach point -- a VOR -- without hitting anything. Not a pleasant situation to be sure, but you do have an out. Assuming you dial that VOR in....
 
MAKG1 said:
Yeah, but if you're anywhere on that approach above minimums, you can fly direct to the missed approach point -- a VOR -- without hitting anything. Not a pleasant situation to be sure, but you do have an out. Assuming you dial that VOR in....
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Yup. It's just fascinating how well they wedged it into the Gunnison valley. W Mountain pretty much grows right out of the side of the runway there.
 
denverpilot said:
Yup. It's just fascinating how well they wedged it into the Gunnison valley. W Mountain pretty much grows right out of the side of the runway there.
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If you don't have the required visual reference until the step-down, the descent angle is over 10 degrees. Not a happy prospect for a jet airplane. That's why the RNP AR approach to Runway 24 was one of the early designs of that category of approach. Not many can fly it, but the well-equipped higher-end airplanes that can have a far safer approach.
 
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