bookworm wrote:
But you were advised that you were cleared for the approach, so I’m trying to probe what that means.
These are two different clearances: first proceed direct maintaining FL and then cleared for the RNAV (once you are already close/high). They were also given by two different ATC: first still by Zurich departure, second by Zurich arrival.
I think that, like a good lawyer, bookworm is asking a question to which he already knows the answer 
The clue might be that “cleared for the approach” implies that you can descend to the IAP platform altitude (4500ft in this case) as soon as the phrase is spoken. Obviously this has the potential for fatal results. Much previous discussion e.g. here here
Can’t resist it…. try this
According to the DFS enroute chart, the MVA on the way from Switzerland to EDTD is 6000 ft. Until established on a segment of the approach (inside TD003 in this case), Vladimir was on a vector, so my vote is that the clearance implied maintaining FL60 until TD003.
From there to the runway gave him 11 nm to lose 4000 ft. I wouldn’t say that’s hard to do.
I’m with everyone else who is bewildered by the FI’s interpretation.
Peter wrote:
The clue might be that “cleared for the approach” implies that you can descend to the IAP platform altitude (4500ft in this case) as soon as the phrase is spoken. Obviously this has the potential for fatal results.
Yes. As soon as Vladimir got the approach clearance, he could start his descent from FL60, but since he was not being radar vectored he would be responsible for his own terrain separation. Since the approach plate doesn’t give a MSA for Swiss territory (which he would be over almost all the way to TD003), he’d have to use the MORA (and in any case the MSA was 6300). At TD003 he could descent to 4500 which would be a bit of a challenge with 4 miles to go to the FAF. Is there a MRVA chart for the area?
The possibility of ATC to give directs instead of radar vectors on an RNAV approach opens up a can of worms as regards terrain separation since ATC has no responsibility for terrain clearance after having given a direct.
jmuelmen wrote:
Vladimir was on a vector, so my vote is that the clearance implied maintaining FL60 until TD003.
No, he was on a direct to TD003, not a vector. An approach clearance means you can descend at your discretion as long as you observe the minimum altitudes.
Airborne_Again wrote:
An approach clearance means you can descend at your discretion as long as you observe the minimum altitudes.
That’s not the case in the US. It could of course be true in Europe, in which case that would be a very interesting difference…
The FAA AIM (section 5-4-6, “approach clearance”) says:
e. The following applies to aircraft on radar
vectors and/or cleared “direct to” in conjunction with
an approach clearance:
1. Maintain the last altitude assigned by ATC
until the aircraft is established on a published segment
of a transition route, or approach procedure
segment, or other published route, for which a lower
altitude is published on the chart. If already on an established
route, or approach or arrival segment, you
may descend to whatever minimum altitude is listed
for that route or segment.
My interpretation is that a clearance for the approach in combination with a direct-to TD003 and “maintain FL060 until TD003” means you should be able to descend from FL060 to 4500 ft within the 4 NM or inform ATC that you will have to fly the full procedure via DONET.
From roughly 6000 to 4500 it is 1500 feet to loose. At a groundspeed of 160KT that would require a descend of 1000 ft/min. Doesn’t seem too hard to do. From the FAF VIBEV the descent would then be much shallower. But then one can slow down earlier too.
I have flown the full procedure earlier this year when coming from the north. It takes a while
If I were flying and got this clearance firstly I certainly wouldn’t be flying the whole procedure (unless unavoidable, but I wouldn’t take the ATC clearance to me to start doing that).
I would evaluate whether me in my airplane can do the descent (whatever it may be) safely in the required distance. If it means slowing and taking flaps in anticipation of it or something then so be it. If I thought it couldn’t be done I would see if it was possible to descend any more, firstly by altitudes on the chart, then by asking ATC for descent if possible since they may be able to descend you lower on radar and then I’d probably think about making it a visual if I had the field in sight. Asking if you can make the approach via TRA would also be an idea since you could then descend sooner.
One thing that I think is useful and don’t hear many people using is a radar monitored descent. It may not be strictly relevant here but it’s useful if given/requesting your own navigation or self positioning for the approach. It basically lets ATC take care of the descent while you do the lateral. I have heard it used a lot at one particular airport in the UK (where I learned of it’s use first) and I have since requested it at other airports (in the UK admittedly) with success.
jmuelmen wrote:
Airborne_Again wrote:
jmuelmen wrote:
A
jmuelmen wrote:
An approach clearance means you can descend at your discretion as long as you observe the minimum altitudes.
That’s not the case in the US. It could of course be true in Europe, in which case that would be a very interesting difference…The FAA AIM (section 5-4-6, “approach clearance”) says:
e. The following applies to aircraft on radar
vectors and/or cleared “direct to” in conjunction with
an approach clearance:
1. Maintain the last altitude assigned by ATC
until the aircraft is established on a published segment
of a transition route, or approach procedure
segment, or other published route, for which a lower
altitude is published on the chart. If already on an established
route, or approach or arrival segment, you
may descend to whatever minimum altitude is listed
for that route or segment.
Isn’t that the same thing EU/US wise? ATC clears you direct “approach fix xyz” and adds “cleared approach”. As soon as you reach the fix and start the approach procedure you can descend further…
