When to press the Appr button?

[vololiberista 205]

Most has been said here. Just always remember not to arm the APPR button if the ILS indicates that you are above the glide slope. Descend accordingly if so. Another point to remember. ILS sytems "prefer" to capture the localiser first (And this how one is trained to operate using the ILS). Meaning that if they capture only the GS the a/c will not descend. In order to start the descent on ILS the a/c must already be established on the localiser. At 10nm out you should intercept the GS below 3,000 AGL. Thus allowing the a/c to line up with the localiser before intercepting the GS. The doctrine: "A good landing is made from the top of the glide slope". Should always be kept in mind. Also remember (even though it is just a sim meaning you can do what you like) that at major airport such as EGGL pilots must always use the ILS and not make a visual approach. SVFR approaches are only granted by PPR, when there is little traffic and when weather conditions permit.Vololiberista

[rsrandazzo 6,353]

Gents-Proving once again that there are no "right" answers in aviation- let me give you a different spin.Our line's operating procedures for thet LOC/APR modes were as follows:LOC: Press when you get "cleared to intercept" an ILS. This instruction implies that you are cleared to use the approach path, but not cleared to descend... As such, using LOC will satisfy this criteria.APP: Press when you get "cleared for the ILS approach" from ATC. It is important to note that (in the real world) no ATC worth his salt will clear you for the ILS approach whilst you are still above the G/S. In my career I've never had it happen... for what that matters.... Well- there was that one day on VATSIM... but that was back in '96. :-p

[ferrabras 0]

I'm in my 15th JS41 flight and never used AP for ILS approach :( ! From what you are saying I'll keep following GS and LOC by hand :(

[vololiberista 205]

I'm in my 15th JS41 flight and never used AP for ILS approach :( ! From what you are saying I'll keep following GS and LOC by hand :(

Ok if you wish as it's only sim! But, if you are flying in UK airspace and wish to land at an airfield equiped with ILS you must and I repeat "must" not fly a visual approach unless you have PPR (Prior permisson required). What this means is that you must fly the ILS using the autpilot.Vololiberista

[dbw1 445]

Basically never hit the APP button till you're on the final vector for LOC intercept and have been CLEARED for the approach.

[Deano777 0]

dbw1Not technically correct, Cleared for the approach is different to being cleared to intercept the LLZ, in both cases the APP can be armed. (But you mustn't descend on the glide without clearance)VololiberistaJust because you don't arm the APP (which is basically the Flight Director) it doesn't mean you are conducting a visual approach. You can quite easily fly a raw data ILS without the aid of the Flight Director & Autopilot.

It is important to note that (in the real world) no ATC worth his salt will clear you for the ILS approach whilst you are still above the G/S. In my career I've never had it happen... for what that matters.... Well- there was that one day on VATSIM... but that was back in '96. :-p

RobTry flying into Amsterdam Schiphol, it's a frequent occurrence ;)

[dbw1 445]

Actually. based on 30+ years of doing it for a living (and i acknowledge different sop's exist for different companies) were one cleared to intercept the LOC or LLZ I would hit the LOC button. Were I cleared to intercept the LOC for an ILS (dnot yet have approach clx) I would hit the LOC button. Only after I received Approach Clx would I hit the APP button as only then would I be cleared for the Approach and own the airspace to the ground. Also, I acknowledge these procedures may vary from aircraft to aircraft.

[michal 44]

Actually. based on 30+ years of doing it for a living (and i acknowledge different sop's exist for different companies) were one cleared to intercept the LOC or LLZ I would hit the LOC button. Were I cleared to intercept the LOC for an ILS (dnot yet have approach clx) I would hit the LOC button. Only after I received Approach Clx would I hit the APP button as only then would I be cleared for the Approach and own the airspace to the ground. Also, I acknowledge these procedures may vary from aircraft to aircraft.

I don't know where you fly but in the US it is pretty much standard that your clearance for the LOC and ILS approach comes at the same time and it sounds something like this:XXXX, turn right heading XYZ, maintain xxxx (altitude) until established on the localizer. Cleared for the ILS runway XX ...I have only done GA IFR flying and I never heard a separate clearance issued for localizer and the approach. Perhaps if you fly big iron things could be different.

[Deano777 0]

dbw1Granted, but you said it yourself, quote - never hit the APP button till you're on the final vector for LOC intercept and have been CLEARED for the approach.What I was saying is that technically this is not quite right, because you can still hit the APP button when cleared to intercept the LLZ only, nothing is stopping this from happening. It is only your company's SOP that dictates you can't.It used to be my company's SOP to only hit LOC (or NAV in our case) when cleared to intercept only, but now it has been replaced with hitting APP when within 90

[ckyliu 1,749]

In the United Kingdom you cannot be "cleared approach" in conjunction with ILS or Microwave, unless it's a self-positioned approach (See CAP413, page 206, also see 9.4.2 in CAP493). The instruction to descend on the ILS is given separately from clearance to join the localiser, although the two maybe combined into one transmission if the glidepath clearance is conditional and there's no conflict with procedure.I wouldn't press the APP button on the AP until you had received clearance to descend on the glidepath, because you might end up descending without authorisation. You'd have to use another LNAV mode in the interim. Even when flying overseas I wouldn't press the APP button until I'm sure I'm not going to descend in to anyone or anything.廖傑英 (Chris)

[dbw1 445]

In the USA things are done differently from Canada. Cleared for the approach is standard phraseology here when cleared for any kind of approach. Even if you are cleared to intercept the localizer until you are "cleared for the approach" you do not start down from your last assigned altitude. I never hit the APP button till actually cleared for the approach. Different strokes for different folks I guess.

[Deano777 0]

dbw1To be honest that is the best way of doing it how the Americans do it, sometimes over here you can be caught short because you are on the LLZ and going past the glide, ATC can't get a word in to clear you on the Glide. It is obvious you are going to go down the approach so why we don't just "clear a/c for the approach" is a mystery. The French do it, they even clear you to land when there is an aircraft ahead of you (in CDG). I just get the feeling we over complicate it over here waaaay too much.

[ckyliu 1,749]

We can do both of those things in the UK. As I said, if local procedures are not restrictive, ATC can issue "When established on the localiser, descend on the glidepath". In the past I have occasionally been caught short thanks to RT congestion, unable to report established, but the aforementioned instruction avoids this situation. I don't know if such practise is acceptable in Canada, but I thought their procedure was very similar to the States? You chaps are even still using inHg for baro refs, all in the interests of commonality!Furthermore, aircraft can be cleared to land with aircraft ahead them, which is known as a conditional landing clearance: "BIGJET 347, runway 28, land after the B737, wind calm" - CAP413 1.9.3, although this is only permitted in daylight and good weather, for obvious reasons. I'm not familiar with French phraseology or rules, but I would guess they're broadly the same.廖傑英 (Chris)

[Deano777 0]

ChrisI'm aware of the "When established on the LLZ, descend on the ILS", which is common over here, this still over complicating it to a point. The land after call is not the same as being cleared to land with an aircraft ahead. They are inherently different.

[vololiberista 205]

The most commonly used procedure at EGLL is to bring a/c down to 2,500ft at about 13 DME then "Call established on the localiser" thus giving time for an ATC response to "Descend on the ILS". The ATC procedure will vary from airport to airport dependant on local conditions, terrain and traffic. The system works well at EGLL. I have rarely heard a go around call.Vololiberista