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EASA All-weather operations NCO - finally we may have GPS substitution for ADF/DME

PepperJo wrote:

Meaning you would need the VOR or ADF which defeats the purpose of substitution.

If they are in the final approach segment in the US you also need an ADF. This will allow substitution in the missed for example. The US doesn’t allow complete substitution unless there is an overlay approach.

EGTK Oxford

There is usefulness for all the RNAV approach where the missed approach is based on a NDB (a UK favorite) or to fly DME arc

Nympsfield, United Kingdom

Meaning you would need the VOR or ADF which defeats the purpose of substitution.

Exactly; it makes this worthless because if equipment carriage is required that’s what we have now, and “everybody” flies it using a GPS, and because the GPS is not officially used, it doesn’t have to comply with any requirements

There is usefulness for all the RNAV approach where the missed approach is based on a NDB (a UK favorite) or to fly DME arc

That’s a fairly marginal case though, Europe-wide.

Does this mean that if you have a straight NDB approach, say LDLO or many other places, you still have to carry an ADF?

Administrator
Shoreham EGKA, United Kingdom

The change makes it consistent with the US approach to the subject.

EGTK Oxford

In that case I struggle to see the use of it in Europe, unless Europe develops official overlay approaches, which is exceedingly unlikely due to the required resources.

Often, the “Threads possibly related to this one” links below a thread are worth a look, and here we have this one where much of this was done before

Administrator
Shoreham EGKA, United Kingdom

I found this a bit strange, in section 4.3.1 of the NPA:
It is notable that the difficulty of LVTO is likely to scale with the speed of the aircraft. A take-off in an RVR of 300 m in an aircraft with a 65-knot rotation speed might be compared to a take-off in an RVR of 600 m in an aircraft with a 130-knot rotation speed.

Isn’t take-off/rotation distance a quadratic function of speed, like landing distance (i.e. double the touch-down speed and we roughly quadruple the braking distance)?

Also, does anyone know where the proposed 150 m LVTO RVR came from? In touring aeroplanes with half-decent performance do we really need to see enough runway to take off and land again?

Fortunately, none of this is readily enforceable down in this forgotten corner of the PRJ.

Last Edited by Jacko at 07 Feb 22:26
Glenswinton, SW Scotland, United Kingdom

If they are in the final approach segment in the US you also need an ADF.

Seems not to be true any more:

https://aviation.stackexchange.com/questions/35904/can-a-pilot-use-their-gps-fms-to-fly-a-vor-or-ndb-approach

It’s somewhat moot anyway since I doubt if there are any approaches which haven’t long since had a GPS overlay.

KPAO, United States

Jacko wrote:

Isn’t take-off/rotation distance a quadratic function of speed, like landing distance (i.e. double the touch-down speed and we roughly quadruple the braking distance)?

Sure, but they’re not talking about aircraft performance but rather about what visibility/RVR the pilot needs for a safe take off. That would depend on the time it takes for the aircraft to travel a length of runway and that in turn is directly proportional to takeoff speed.

Last Edited by Airborne_Again at 08 Feb 08:02
ESKC (Uppsala/Sundbro), Sweden

Snoopy wrote:

Is it OEM dependent? For instance (earlier) Cessna G1000 are RNAV1 and Diamond are not? Can it be upgraded?

In principle the difference could be due to different software versions, but I think it is more likely that the installation approvals are what the manufacturer asked for (i.e. needed to provide evidence for) and/or what the particular competent authority agreed to approve.

In the case of Cessna it is the FAA that approved the POH so it is the FAA that would have to be convinced. In the case of Diamond it is EASA or the Austrian competent authority. Recall what I wrote in an earlier post that European authorities used to be reluctant to give RNAV/RNP-1 installation approvals.

An upgrade for the DA40 would most likely be a paper-only exercise but it could cost a lot in money and effort.

ESKC (Uppsala/Sundbro), Sweden

the installation approvals are what the manufacturer asked for (i.e. needed to provide evidence for) and/or what the particular competent authority agreed to approve.

Yes, and there is a huge element of “I am an old fart in the CAA and I need to justify my job until I retire and if I just agreed to something – especially something the nasty reckless Americans (who brought us MacDonalds and KFC!!) agreed to – then I need to be stricter, otherwise somebody might realise think I don’t understand how GPS works, and next time I have lunch at the Royal Institute of Navigation I will be taken the p1ss out of”

Years ago I was at a presentation by a very senior UK CAA official (a “captain”) on GPS approaches. He said you needed a specially approved GPS to fly them (can’t recall the detail; probably RNAV1). Afterwards I pointed out to him that (at the time, at least) France allowed any BRNAV approved installation for flying GPS approaches. Of course this was also the case in the US, with the KLN94 being fully capable, subject to an AFMS. He made a most unhappy face but since nobody else heard the conversation he said “they can do what they like”, turned around and walked away

It was 100% a case of just imposing a higher standard to show that you “know something”.

In the Socata case – getting an AFMS approved by some old fart in the DGAC which prohibited GPS approaches for both the KLN94 and the GNS430 – nobody cared because back in 2002 99% of owners had no idea what an AFMS is (today maybe 95% ) so they flew them anyway and everybody was happy. AFAIK virtually all American TB owners never knew about the AFMS either and “just flew the planes”. A few got a custom AFMS done by the disti, Socata in Florida; I obtained a copy of one for a template but sent it to a UK avionics shop to do one for me and they lost it

But since pilots like to get strictly legal in every respect we end up debating which exact type of GPS and which AFMS wording can substitute for an NDB

Ultimately “everybody” flies NDB and VOR approaches using a GPS, so the value of this concession comes down to whether you can legally avoid the carriage of an ADF (VOR is not a problem; almost every VHF radio does VOR/LOC/GS) which is a big box which is not reliable, difficult to repair, and forces many to buy replacements from US Ebay and use a hair dryer to move the serial number stickers over Also DME, but DME is awfully useful for ILS approaches which are still key in Europe and are likely to be for many years.

However the value of this concession is reduced because there is no known enforcement; e.g. huge numbers of SR22s came into Europe with no ADF or DME. If hundreds of these pilots had been busted and fined, we would be climbing all over this new EASA proposal.

And unless the ADF can be dispensed with in every scenario, you still have to carry it, so I fail to see the value proposition here. It just seems to legalise what people do anyway and what is utterly undetectable.

Administrator
Shoreham EGKA, United Kingdom
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