GPS Approaches

[Capt. Manuvar]

1. Are there any GPS approaches in the UK?
2. If there are, how common are they?
3. What is the general attitude towards GPS approaches from pilots, airports and the CAA?
I'm flying outside the UK at the moment that's why I'm asking.
Capt. M

[Chilli Monster]

1. No
2. See above
3. CAA are still doing feasability studies (albeit slowly). Watch this space

[Capt. Manuvar]

Quite sad actually, cos Canada (as long as many other countries) decided to get rid of NDBs withing the next two years. A lot of airports over there have GPS approaches.
I flown a few GPS approaches and they are straight forward.

[mazzy1026]

I flown a few GPS approaches and they are straight forward.

Excuse the Pun :D :ok:

[tmmorris]

If NDBs are to be withdrawn then clearly GA needs GPS to be approved for en-route navigation as well as approaches PDQ (or Galileo, I suppose!) - otherwise how do you navigate IFR (legally) outside CAS in e.g. the Gloucester/Shobdon/Welshpool area?

Tim

[Aim Far]

how do you navigate IFR (legally) outside CAS in e.g. the Gloucester/Shobdon/Welshpool area

Compass and stopwatch old boy. :)

I don't think there's any requirement within the rules for enroute IFR (off airways at least) to use any ground based navigational aids. It always helps to know your position of course but its not a requirement as such.

Give me a GPS any day.

[S-Works]

AimFar, not sure you are correct there. As I recall it there is a requirement for being able to use radio aids on and off airways. I need to dig out the reference but I definatly recall an exam question on it. Off airways it is x number of miles.

[Chilli Monster]

bose-x

Don't get confused between U.S and U.K regs - I know what you're thinking of here.

U.K - equipment requirements for IFR flight outside CAS do not require ANY radio nav aids to be carried - just compliance with the quadrantal and minimum height rules. (ANO sched 5 and associated articles)

U.S - you're thinking of the maximum distance between navaids that you should have which differs whether you are on or off published airways. (off airways - 80 nm below 18,000ft - AIM 5-1-7 (c)(3)(c))

[S-Works]

Chilli,

well pointed out! yes it is FAA regs that I am thinking of as I dont yet hold a JAA IR!

[tmmorris]

Indeed, Aim Far, been there, done that, scared the passenger (ATPL...). Of course we had a GPS switched on for backup...

Tim

[IO540]

If there is an NDB at the FAF, which one flies over and the ADF needle swings around, what would they replace it with, short of a full GPS approach?

They could put in a VOR but those are a lot more expensive to run than NDBs.

[M609]

Just curious, is the UK CAA looking at SCAT-1 and LAAS installations at all? Would it be interesting for UK GA and commuter airfields you think?

(My employer just signed a deal for installations at 25 regional airfields, in a joint venture with Wideroe Airline)

[reynoldsno1]

If there still "looking" at the feasablility of GPS approaches, I think you'll find GBAS is a long way off.......

[Capt. Manuvar]

I've come across two types of GPS approaches in my limited experience so far. There are GPS overlays for existing approches (NDB, VOR,....). Then there are stand alone GPS approaches, which only require a certified GPS reciever. These come in the same "T" shape. An 5nm intermediate section to the IAF 90Deg to the final approach track. The final approach segment consists of two 5nm legs, IAF-FAF and FAF to MAPt. They are very easy to fly since you don't have procedure turns or timing worry about. They are all the same shape. The neatest thing is that a few decent GPS units (e.g. Garmin 430) will even tell you when to turn to intercept the final approch track. You don't have to think too much about wind correction since your magnetic TRK is displayed on the GPS reciever.
In short any muppet who can hold ALT/HDG/SPD in IMC (just like me :E) can fly a perfect GPS approach.

[A and C]

Hidden away deep in an AIC there is admision that GPS aproaches are leagal in UK registered aircraft provided the GPS in the aircraft has the aproach in the data base.

It is also my understanding that they have also approved an american airline to do GPS aproaches at LGW if the ILS is Inop due to the fact that this airline has not got ADF fitted !.

[IO540]

Hidden away deep in an AIC there is admision that GPS aproaches are leagal in UK registered aircraft provided the GPS in the aircraft has the aproach in the data base

The AIC isn't the ANO :O We could start another discussion on this... It is just like the IMCR minima being the IR minima increased to 500/600ft - most likely a CAA advisory thing but not law.

On a UK private flight, one can do a DIY instrument approach in any way one wants to. A 100% GPS instrument approach is 100% legal, and a fair number of people do just that - they just don't talk about it.

If I had my own farm strip, with no nearby hills, I would do them too. But I would probably put up an NDB, activated by a SMS message and turning itself off after 20 mins :O

[DFC]

GPS approaches approved in the UK; and

UK Aircraft approved for GPS approaches

are two totally separate issues.

There are no GPS approaches approved in the UK.

There are plenty of UK aircraft with the required equipment and approved to make approved GPS approaches (where they are legally established - in countries other than the UK).

As for home-made approach..........since the lowest height legally allowedin IMC under IFR is 1000ft above all obstacles within 5nm of the aircraft...........there is little to be gained by using GPS over a VOR/DME some 20nm away or even some ndb/ndb crosscut.

"most likely a CAA advisory thing but not law."

Not law - but one would be reckelss to ignore the advice of the foremost UK safety authority and thereby cause accident and/or injury and/or endangerment.

Reckless operation / endangerment is clearly spely out in the law!

One of the probable reasons why the CAA are taking a cautious line with regard to GPS approaches is because one of their own was killed in a helicopter accident some years ago...........while the G reg helicopter was making a home-made GPS let-down in the UK!!!!!

Regards,

DFC

[IO540]

since the lowest height legally allowedin IMC under IFR is 1000ft above all obstacles within 5nm of the aircraft

Except when taking off or landing ;)

As regards a helicopter crash, why isn't the USA covered in aircraft wreckage, caused wholly by people doing GPS approaches?

[reynoldsno1]

GPS approaches coded into databases contain more than just a series of waypoints. The functionality of the receiver changes during the approach as well.
If you want to do a DIY approach, please make sure you do it solo to minimise trauma to all the families involved...

[WelshFlyer]

I think it's a bit sad that NDBs are going down the pan - I acctually like navigating on them.

Up here 'round Caernarfon EGCK we like using the radio wales transmitter (882Khz) as a bid NDB...Good fun telling friends we have special computer navigation - radio wales and the laws of radio physics.

But I suppose GPS is the way to go...

WF.

[DFC]

IO540, - Except when taking off or landing

Yep, that is what it says in the ANO under Instrument Flight Rules.

However, think of it like this when dealing with GPS -

One can not complete an approach that is not in the databse. There are no approaches in the UK.
Thus when in the UK, most approved GPS units are limited to BRNAV which has an RNP of 5.

Since the unit is only by virtue of the RNP5 certified to be accurate to within 5nm of the indicated position for 95% of the time, you must considder all obstacles within that 5nm unless you can avoid them visually.

Remember that RNP5 is acheived on the ATS routes where the VORs are not more than 100nm appart!!!!...........so when it comes to using the equipment in accordance with the approvals within the UK you are just as good using a VOR 50nm away!!!

Also considder what it says in the AIP about required visual reference before descending below the applicable height that provides the required obstacle clearance.

GPS is very accurate. So is my flying..........but I can't just use that as the basis for flying CATIIIC approaches..........unless the aircraft is approved and the ILS/airfield capable.

Regards,

DFC

[tmmorris]

Maybe inadvisable, DFC, but you still haven't shown them to be illegal for private flights. Indeed the CAA published a paper (last year? what happened to it?) discussing two separate issues:

(a) approving approaches at airfields with only a FIS;
(b) making non-approved approaches illegal for all flights;

making it quite clear that at the moment the latter are not illegal. They wanted to tie (a) to (b) as a sweetener for (b).

Or are you suggesting that home-made NDB and VOR approaches are legal, but home-made GPS ones not? Not sure how that could be justified.

Tim

[IO540]

I think that all the time it is legal to choose freely to go "IFR" outside CAS, they cannot practically outlaw DIY descents through cloud. The best they could do is enforce a minimum MDH of 1000ft - the IFR MSA.

Let's face it, such a pilot isn't going to be flying a normal procedure where one goes overhead a beacon, then straight for 6D or whatever, then a rate 1 turn onto the inbound track, then a stepdown descent when within 5 degrees (of an ADF track which is probably itself some 20-30 degrees out...)

What he will do is fly to a point which is on the extended centreline of the runway, say 3 miles away, get there 1000ft above the terrain, and just fly the GPS-supplied runway-aligned track all the way to going visual.

And if there are no obstacles, that should be as safe as any navaid. The FAA seem to reckon so, and they have far more planes over there than the CAA.

[DFC]

Does the FAA all ow pilots to fly DIY GPS approach procedures?

or

Does the FAA require that a GPS approach procedure be approved and contained within the database?

Yes, currently DIY "cloudbreak" procedures are permitted by the UK CAA. It can't be called an approach procedure because such a procedure requires ATC.....hence the proposals spoken of above.

If a person decides to design a "cloudbreak" procedure then it is incumbent on them to apply the appropriate obstacle clearances as laid down by the CAA............This usually requires a survey of the area if anything less than 1000ft above obstacles (enroute minima) is used and requires plenty of forethought and planning.

It would be a shame to be completing the perfect GPS letdown at the local club only to colide with the other non-radio guy doing the same in a slower aircraft!!!!!

GPS is super accurate. Home made approaches are full of danger for the unwary..and most of the dangers are unrelated to the guidance system.

Regards,

DFC

[ShyTorque]

tmmorris,

You asked: "Maybe inadvisable, DFC, but you still haven't shown them to be illegal for private flights. Indeed the CAA published a paper (last year? what happened to it?) discussing two separate issues:"

There was an outcry against the proposal by a number of commercial operators. One can imagine why - i.e. folks would be prevented from doing what they have already been doing for some time..... and the CAA, to their credit, are thinking again. There are places in UK where there are "private" letdowns based on GPS, these have been properly surveyed and are known to the CAA.

Hopefully the next step is for the CAA to admit that properly surveyed GPS approaches, flown by properly trained crews, in properly equipped aircraft ARE safe and therefore can be approved and formally sanctioned.

;)