Build Your Own LPV? (Don't get your panties in a bunch its a hypo)

[TheGolfPilot]

Don't get your panties in a bunch its a hypo.

Say I live on a ranch and have a nice paved, uncharted runway. How hard would it be to program a LPV approach or even just a plain RNAV approach into a 430w or 530w? Would it have to be on a separate chip, meaning on gps has approved data and gps #2 has my own concoctions?

Again, all hypothetical I was just day dreaming today thinking about it. I don't need a lecture of why its an awful idea! (but of course you can if your heart desires)

 

[John221us]

Well certainly it has been done... Not saying it is right, but rumor has it that there are one or two airports near me with home grown approaches. It might be better to just get under the layer and go VFR (approach at a nearby field). If it is lower than that, then go somewhere else? Sounds like a bad NTSB report to me. I am a VFR pilot though, so what do I know.

 

[N801BH]

Don't get your panties in a bunch its a hypo.

Say I live on a ranch and have a nice paved, uncharted runway. How hard would it be to program a LPV approach or even just a plain RNAV approach into a 430w or 530w? Would it have to be on a separate chip, meaning on gps has approved data and gps #2 has my own concoctions?

Again, all hypothetical I was just day dreaming today thinking about it. I don't need a lecture of why its an awful idea! (but of course you can if your heart desires)

I have a private ranch with a 3000' runway.......

Easiest way is to fly the approach just like you want in VFR conditions and save that into a "user defined" fix Works good on my old King KMD 150...

Not that I would use it during low visibility conditions.......

 

[Kritchlow]

I have a private ranch with a 3000' runway.......

Easiest way is to fly the approach just like you want in VFR conditions and save that into a "user defined" fix Works good on my old King KMD 150...

Not that I would use it during low visibility conditions.......

As long as you have VFR minis, I don't see why you can't use it for guidance.

 

[FORANE]

I don't know if it can be done with a 430/530. Some of the experimental EFIS's have this capability.

 

[jtheune]

My question would be this: How would ATC release you to a lower altitude for a unknown/homemade approach? Would you cancel IFR while IMC at altitude? If it's VMC then why would you need the approach?

I thought there was a way to request that a approach be created to a private strip although I'm sure it would take a long time and perhaps cost some money.

 

[weilke]

Someone wrecked a commander on a home-brew VOR approack to a private strip in PA in the 70s. It is frowned upon.
There are companies that will design a private approach for you, do a survey etc.it is mostly a helicopter thing, but for the low price of 200k they will design a fixed wing approach and shepherd it through the airspace study and approvals. If you are landing a 3.5mil King Air on your private 4000ft paved strip that's not even money.

 

[flyingron]

I have a procedure to fly the ILS into SVH and if I break out VFR I have some waypoints that take me scud running into my grass strip (NC26). If I don't break out I can continue to the DH and land at SVH (20 minute drive in the car).

Vertical guidance I've never seen the need. I do have a military surplus VASI but we've not really had a lot of success with it.

 

[Gucci Pilot]

You could put them in as user defined waypoints. I don't remember if you can manually change the sensitivity on the 430/530 or not.

 

[Kritchlow]

You could put them in as user defined waypoints. I don't remember if you can manually change the sensitivity on the 430/530 or not.

Right.. You can file lat/long.

 

[Velocity173]

User defined waypoints would work. Since you want LPV, glide path would be the problem. On our old Chelton we could fly "highway in the sky" but I believe it only gave it for established precision or non precision approaches. Some experimental stuff might give you a glide path though.

I've done a bunch of quasi LPV approaches in the Army (below) that you set up yourself but that was TERPd out and emergency only. Wouldn't want to design an approach into my home field unless I had some basic TERPs experience.

 

[RussR]

https://www.faa.gov/air_traffic/flight_info/aeronav/procedures/ifp_initiation/

You can request an IAP straight from the FAA. Instructions above. For a private approach, there will be an associated cost.

 

[aterpster]

Don't get your panties in a bunch its a hypo.

Say I live on a ranch and have a nice paved, uncharted runway. How hard would it be to program a LPV approach or even just a plain RNAV approach into a 430w or 530w? Would it have to be on a separate chip, meaning on gps has approved data and gps #2 has my own concoctions?

Again, all hypothetical I was just day dreaming today thinking about it. I don't need a lecture of why its an awful idea! (but of course you can if your heart desires)

Disregarding the hypothetical violations of 91.175 and 91.177 you can't home brew an LPV approach. There is a complex path record that must be in the database. An emulated LNAV-only approach is possible but you would have to force terminal sensitivity. Approach sensitivity, accuracy, integrity are not possible. Again, those have to be in the database.

Speaking hypothetically again, if the FAA or one of the approved third-party vendors were to design it, so it could be in the database, the runway would have to have an approved survey (vertical survey for LVAV or LPV), appropriate runway markings and the required surfaces would have to be free of obstacles. Finally, ATC would have to accept it, but they usually do except in congested airspace.

 

[aterpster]

https://www.faa.gov/air_traffic/flight_info/aeronav/procedures/ifp_initiation/

You can request an IAP straight from the FAA. Instructions above. For a private approach, there will be an associated cost.

For a public approach, presently there would be approximately a two-year wait once the surveys were completed and the regional flight procedures team approved it.

 

[AustinPilot]

Better off just installing your own PAPI since you'll need to be VFR anyway.

 

[FORANE]

Synthetic Approach to Your Backyard Strip


http://www.vansairforce.com/community/showthread.php?t=82914

 

[JHW]

no pavement needed

the way we do it is to file and fly the approach to a "real" airport nearby. When I switch to tower I check in with "ILS blah blah option for VFR to the south". They know us. After breaking out I can look down the valley and make a judgement call. If i like what I see, I tell tower I'm breaking off the ILS to fly down the valley and have a look. The peaks will be sticking into the clouds, so I won't commit to it until I get far enough down the valley to see around the first corner. At that point if I tell tower goodbye then I'm on my own to land somewhere. We then have about 50NM to cover through the valleys. Along the way if the weather comes down too much for comfort, there are a couple places to bail out and follow railroad tracks through passes that lead to open country where there is a gliding club and another turf runway, both with wide open approaches.

The weather here is a lot like british columbia, we have plenty of clouds, rain, and ice. But there's almost always a path to get back to the farm underneath it. Here's what it looks like at the end.

 

[FORANE]

the way we do it is to file and fly the approach to a "real" airport nearby. When I switch to tower I check in with "ILS blah blah option for VFR to the south". They know us. After breaking out I can look down the valley and make a judgement call. If i like what I see, I tell tower I'm breaking off the ILS to fly down the valley and have a look. The peaks will be sticking into the clouds, so I won't commit to it until I get far enough down the valley to see around the first corner. At that point if I tell tower goodbye then I'm on my own to land somewhere. We then have about 50NM to cover through the valleys.

So when breaking off the ILS, you request cancel IFR correct?

Before my home field had an approach we typically would fly the ILS at the nearby TRSA field, then cancel and fly scud run VFR to my home field.

 

[JHW]

So when breaking off the ILS, you request cancel IFR correct?

Before my home field had an approach we typically would fly the ILS at the nearby TRSA field, then cancel and fly scud run VFR to my home field.

yes, exactly, but in reality they are still holding the ILS airspace for me until I tell them I'm not coming back. The airline traffic is concentrated around certain times of the day so as long as I avoid those times, it's easy for everyone to get along.

 

[poadeleted20]

https://www.faa.gov/air_traffic/flight_info/aeronav/procedures/ifp_initiation/

You can request an IAP straight from the FAA. Instructions above. For a private approach, there will be an associated cost.

...somewhere around $30K. You'll have to hire a private contractor to develop the approach, and then the FAA will flight test and approve it. It will appear in the regular database for your GPS, although you will control distribution of the approach chart to use it.

As for just programming your own LPV approach without going through the process, it cannot be done. You can certainly program a series of waypoints, but you cannot get vertical guidance. If you do program a sequence of waypoints in the FPL, the system will not go into approach mode, leaving you with only terminal precision lateral guidance. Further, ATC will not be able to clear you for such a procedure, so you'll be stuck with the MVA as the lowest altitude they can give you, and, of course, it would be illegal to descend further without the airport in sight and clearance for a visual approach (or being in VMC and able to legally cancel IFR).

 

[cheemsaf]

This brings out terms like "contact approach", "request min vectoring altitude", "SVFR". Although a contact approach on an uncharted field may be tough to explain to ATC as I've never tried it.

Check this out...MVAs & MIAs. It may help you understand how low ATC will allow you to go and remain IFR in your area. http://www.faa.gov/air_traffic/flight_info/aeronav/digital_products/mva_mia/mva/

Look at 5-5-3 for contact approach: http://tfmlearning.faa.gov/Publications/atpubs/AIM/Chap5/aim0505.html

& lastly, SVFR...aka legalized scud-running
https://www.law.cornell.edu/cfr/text/14/91.157

 

[flyingron]

The FAA takes a dim view to people using contact approaches to fields without instrument approaches (which they won't authorize) or to conduct an approach to one field with the intent to divert to another.

From the AIM:

It is not intended for use by a pilot on an IFR flight clearance to operate to an airport not having a published and functioning IAP. Nor is it intended for an aircraft to conduct an instrument approach to one airport and then when "in the clear" abandon that approach and proceed to another airport.​

Now on the other hand if you can get breakout in VFR or (if you're in the airspace formerly known as a control zone) Special VFR conditions you can certainly switch from a published approach to the other airport.

Dave Wartofsky used to publish a plate for "ILS 19R to ADW and Special VFR to VKX"

 

[James331]

...somewhere around $30K. You'll have to hire a private contractor to develop the approach, and then the FAA will flight test and approve it. It will appear in the regular database for your GPS, although you will control distribution of the approach chart to use it.

As for just programming your own LPV approach without going through the process, it cannot be done. You can certainly program a series of waypoints, but you cannot get vertical guidance. If you do program a sequence of waypoints in the FPL, the system will not go into approach mode, leaving you with only terminal precision lateral guidance. Further, ATC will not be able to clear you for such a procedure, so you'll be stuck with the MVA as the lowest altitude they can give you, and, of course, it would be illegal to descend further without the airport in sight and clearance for a visual approach (or being in VMC and able to legally cancel IFR).

I'd imagine you could start going through the Jepp downloads, see how things are formatted and make a "edit" if you had the tech background to pull it off.

Of course this would not be kosher and I'm not sure how the 400/500 series boxes verify the data on the card.

Personally I'd just make a series of way points with step downs, leave a good margin, make sure you have a good source for a altimeter setting, etc.


Or maybe see if you can just buy a tacan setup off gov liquidations

 

[narchee]

Now on the other hand if you can get breakout in VFR or (if you're in the airspace formerly known as a control zone) Special VFR conditions you can certainly switch from a published approach to the other airport.

Dave Wartofsky used to publish a plate for "ILS 19R to ADW and Special VFR to VKX"

So that works for VKX since it has weather reporting capabilities but if we're talking about a private field that does not have that, SVFR is not allowed as far as I'm aware. Or in this hypothetical example does the private field that you're building your own LPV for have weather reporting?

 

[FORANE]

This brings out terms like "contact approach", "request min vectoring altitude", "SVFR". Although a contact approach on an uncharted field may be tough to explain to ATC as I've never tried it.

Check this out...MVAs & MIAs. It may help you understand how low ATC will allow you to go and remain IFR in your area. http://www.faa.gov/air_traffic/flight_info/aeronav/digital_products/mva_mia/mva/

Look at 5-5-3 for contact approach: http://tfmlearning.faa.gov/Publications/atpubs/AIM/Chap5/aim0505.html

& lastly, SVFR...aka legalized scud-running
https://www.law.cornell.edu/cfr/text/14/91.157

I used to request minimum vectoring altitude prior to my airport getting an instrument approach procedure. Definitely an option.

The contact approach clearance would not be issued for a couple of reasons. One is the destination must have a published instrument approach procedure. The other reason is the destination must have weather reporting i.e. an atis which is presumably also not present.

SVFR on the other hand may be an option. Complete an approach at adjacent airport then break off the approach and proceed VFR or SVFR to destination. I don't have any experience with SVFR though.

 

[Velocity173]

So that works for VKX since it has weather reporting capabilities but if we're talking about a private field that does not have that, SVFR is not allowed as far as I'm aware. Or in this hypothetical example does the private field that you're building your own LPV for have weather reporting?

Yeah but if this guy is close enough to a field that does have an IAP, he can do that and then get cleared out of the surface area SVFR.

We used to do it occasionally at NBC. Had a guy who had a private strip just outside the class D to the north. We'd give him a PAR until he got below the clouds. He'd cancel and request SVFR, the approach controller would take the freq back and clear him to depart the class D SVFR to the north. He'd report his field in sight "radar services terminated, sqk VFR, freq change approved."

Just have to have the right conditions to make it happen.

 

[cheemsaf]

The contact approach clearance would not be issued for a couple of reasons. One is the destination must have a published instrument approach procedure. The other reason is the destination must have weather reporting i.e. an atis which is presumably also not present.

& I guess that's why I've never tried it at random fields before. We used to joke that the Red Barn Approach was more accurate than the VOR approach was. We'd ask for the contact approach instead of being lined up off axis from a VOR many miles away and follow the red barns to the runway. Too bad the red barns are no more

 

[poadeleted20]

I'd imagine you could start going through the Jepp downloads, see how things are formatted and make a "edit" if you had the tech background to pull it off.

No, you can't. The database is protected from such tampering, and any such alterations to it will render it invalid and unusable.

 

[poadeleted20]

SVFR on the other hand may be an option. Complete an approach at adjacent airport then break off the approach and proceed VFR or SVFR to destination. I don't have any experience with SVFR though.

SVFR is permitted only when there is controlled airspace to the surface for the airport to/from which the SVFR operation is conducted. See 91.157 for details. You might get SVFR out of the B/C/D/E-to-the-surface airspace from the airport where the approach was conducted, but unless there were no congested areas below you, you'd almost certainly have 91.119 minimum altitude problems on your way to the other airport once you reached the edge of the B/C/D/E-to-the-surface airspace if the weather really was below 91.155 VFR mins. The SVFR option is really only useful if the other airport is within the same surface-based airspace as the airport with the approach.

 

[EdFred]

No, you can't. The database is protected from such tampering, and any such alterations to it will render it invalid and unusable.

If you have the right decompiler - and have some inside info, you most certainly can. If it's electronic, it can be broken down, reverse engineered, and re-assembled. I ha-, Uh, someone I know has.

 

[James331]

If you have the right decompiler - and have some inside info, you most certainly can. If it's electronic, it can be broken down, reverse engineered, and re-assembled. I ha-, Uh, someone I know has.

I doubt the old software used by Jepp to du those updates is nearly as protected when compared to a copy protected DVD, let alone a iPhone, and those are hacked all day long, I doubt it would take much effort to change the database for a 400/500 series GNS, just not enough, or the right people, care to bother.

 

[EdFred]

I doubt the old software used by Jepp to du those updates is nearly as protected when compared to a copy protected DVD, let alone a iPhone, and those are hacked all day long, I doubt it would take much effort to change the database for a 400/500 series GNS, just not enough, or the right people, care to bother.

All you have to do is download it, and prior to programming it on your card, pop it open. (The file, not the card.) Then write it to the card.

 

[dans2992]

SVFR is permitted only when there is controlled airspace to the surface for the airport to/from which the SVFR operation is conducted. See 91.157 for details. You might get SVFR out of the B/C/D/E-to-the-surface airspace from the airport where the approach was conducted, but unless there were no congested areas below you, you'd almost certainly have 91.119 minimum altitude problems on your way to the other airport once you reached the edge of the B/C/D/E-to-the-surface airspace if the weather really was below 91.155 VFR mins. The SVFR option is really only useful if the other airport is within the same surface-based airspace as the airport with the approach.

What about the "except where necessary for takeoff or landing" clause in 91.119?

 

[James331]

All you have to do is download it, and prior to programming it on your card, pop it open. (The file, not the card.) Then write it to the card.

It wouldn't surprise me if it was just that easy, I really wouldn't bother though, just use a few way points, if you need more precision than that it's probably a bad idea in general.

I was going to build a simple one to some of the larger lakes around here, but I just don't see me ever having a need that great to land there when I could just shoot a normal RNAV or LOC back home.

 

[poadeleted20]

What about the "except where necessary for takeoff or landing" clause in 91.119?

That only applies to the initial climb to the 91.119 minimum altitude or TPA after takeoff or the final descent from TPA or the 91.119 minimum altitude in the pattern or on final. The transit from one airport to another is not exempted under that clause.

 

[cheemsaf]

you'd almost certainly have 91.119 minimum altitude problems on your way to the other airport once you reached the edge of the B/C/D/E-to-the-surface airspace if the weather really was below 91.155 VFR mins.

You just have to watch out for those oh so common "NO SVFR" that are seen on almost every class B airspace in the US if your field coincides with it. Although 91.119 is probably 1K AGL in bravo anyways for congested area, so it's not buying you much imo with the already low class-b vfr mins.

 

[flyingron]

So that works for VKX since it has weather reporting capabilities but if we're talking about a private field that does not have that, SVFR is not allowed as far as I'm aware. Or in this hypothetical example does the private field that you're building your own LPV for have weather reporting?

All VKX had at the time was it's prototype of Dave's SuperUnicom which I don't think had yet been approved for anything operational. The SVFR was to get out of ADW's control zone. After that you only needed the uncontrolled mile and clear of clouds. No ceiling requirement at all.

 

[flyingron]

you'd almost certainly have 91.119 minimum altitude problems on your way to the other airport once you reached the edge of the B/C/D/E-to-the-surface airspace if the weather really was below 91.155 VFR mins.

Have you ever flow into Potomac or Hyde?

Anyway, it's pretty much moot now with the FRZ procedures and the fact that VKX actually has an approach that's usable.

 

[aterpster]

If you have the right decompiler - and have some inside info, you most certainly can. If it's electronic, it can be broken down, reverse engineered, and re-assembled. I ha-, Uh, someone I know has.

If it is an "Hypo_LPV" be sure to get the FAS data block in the exact required sequence; that is, after you have done the vertical survey of the runway end of interest. If these data are not in the correct format "LPV" won't be annunciated. If these data are in the correct format but the engineering and survey math are incorrect, you could be quite surprised where you end up on short final. The Italians did a screw up like that at LIRA (just east of Rome) and the LPV path ended up a half mile, or so, short of the runway.

Here is the FAS data block for F70, which recently went from LNAV to LPV:

 

[JeffDG]

All you have to do is download it, and prior to programming it on your card, pop it open. (The file, not the card.) Then write it to the card.

Are you saying they don't do so much as an MD5 hash to verify the database before accepting it into they system? Wow.

Or do they do an MD5, and you just have to recompute the new one?