Typical altitude call outs on an airline, admittedly multi crew, would be to confirm that any cleared to altitude is MSA SAFE. If on vectors then the call out might be MSA vectors with the MVA being monitored. If not IMC then the call would be MSA visual, but the emphasis is for the crew to be highly sensitised to MSA.
Am not sure how you hit a hill if you do not descend below MSA, unless you lost situational awareness and your MSA is wrong.
On RNP approaches you would normally not be cleared by ATC for the approach until you are within 10NM from the intermediate fix, which will have its own MSA area and crossing altitude.
There was an earlier discussion of being within lateral limits on a procedural outbound descent to platform altitude.
Ibra wrote:
On RV+RNP, I once got vectored to FAF on RNP once, I don’t remember what I did exactly but it worked fine
That is not allowed in US. The closest allowed for the intercept is 2 NM outside the approach gate which is located 1 NM prior to the FAF, so 3 NM before the FAF. It is possible to be vectored closer on an ILS, but the weather must be almost VFR.
NCYankee wrote:
So descent using the MSA is not authorized and is only available in the event of an emergency. With the introduction of TAA (Terminal Arrival Area), these segments are treated as being usable as an RNAV feeder route and as long as the aircraft is inside the TAA and cleared for the approach without any specific ATC instructions to the contrary, pilots are expected to descend to the TAA sector altitude.
Thanks! I had not realised this rather crucial difference between MSA and TAA. It seems to apply also outside the USA. PANS-OPS volume I states specifically that “An aircraft may be manoeuvred at the TAA provided the flight path is contained within the TAA boundaries by reference to bearings and distance to the IAF” while there is no corresponding statement about the MSA.
That is not allowed in US. The closest allowed for the intercept is 2 NM outside the approach gate which is located 1 NM prior to the FAF, so 3 NM before the FAF. It is possible to be vectored closer on an ILS, but the weather must be almost VFR.
It isn’t allowed anywhere, I am sure.
Isn’t this like when ATC vectors you to the ILS LOC but they do it inside the GS intercept, i.e. after the FAF? That happens fairly frequently; I have long lost count. I am sure that’s not allowed either 
because a lot of avionics, not to mention a lot of pilots, would not be able to intercept the GS from above. It’s quite a high workload situation because the required high ROD will make you really speed up.
One difference with approaches that are charted with an RNAV TAA is that it is very rare for there to be feeder routes included. This is because one can use the sector as an RNAV feeder route for any airway route that passes through the TAA segment. The TAA segments are really enormous and can easily span more than 70 NM at their widest point. I have heard that in the US, there may be a few TAA in Alaska that have a TAA and use a feeder route from an airway because no airways pass through the TAA. In the US, some approaches use a TAA, while others use an MSA. Both forms are used for conventional and RNAV approaches.
That is not allowed in US. The closest allowed for the intercept is 2 NM outside the approach gate which is located 1 NM prior to the FAF, so 3 NM before the FAF. It is possible to be vectored closer on an ILS, but the weather must be almost VFR
Does it happen often in US where you get Radar vectors on RNP 2NM before FAF? I see Garmin has VTF option, so likely there is a demand
Getting vectored to 2NM before FAF on ILS, is bread & butter for ATC but I am surprised they also do it for RNP/LPV, it did caught me where I got vectored to LFPT RNP23 (earlier than FAF with a very comfortable distance), it was hectic due to my fat fingers and a surprise of getting vectors while on GPS approach: I had full approach loaded, I did a mistake of pressing direct FAF, so restart from scratch with select RNP23 + direct IAF, then activate intermediate leg and eyeball it with a heading bug 
Yes even if you are vectored before FAF, there are load of caveats depending on make/model of GPS equipment, if you ever dare to intercept with VTF past “2nm gate”
- You get glitches on TERM/APR transition
- VTF deletes all points in FPL including IAF
- RAIM may not run and CDI may not scale
- Missed may not sequence at MAPT on RNP approach
- Automatic GPS/VLOC will not switch on ILS overlay
If you intercept VTF before “30nm gate” you also get glitches on ENR/TERM transitions (you rarely get this)
There is no reason to fly “VTF mode” on GPS, some will say it’s ok if you know what you are doing, it’s a receipt “WTF moment”
Ibra wrote:
Does it happen often in US where you get Radar vectors on RNP 2NM before FAF? I see Garmin has VTF option, so likely there is a demand
It happens. Sometimes it is too close and not doable. Vectors to final is really misnamed. It should be vectors to the intermediate leg. I was once on an approach that the intermediate leg to final approach course involved a 20 degree turn. I was flying a SR22TN with a G1000 Perspective system. The controller vectored me through the intermediate leg at 1000 feet above the FAF altitude and then lined me up on an extended final approach course and cleared me for the approach. Using VTF would want me to intercept the intermediate leg, direct to the FAF would cause the system to generate an error. According to FAA rules, I was not established until at the FAF, so I could not begin the descent. I told the controller I was missing the approach and could not accept the clearance as it was invalid. The reason the controller had me so high was that a nearby USMC facility had F18’s in the pattern. I told the controller, now the supervisor, that I needed to go back to the HILPT and hold until they could permit me to fly the approach as published. I was cleared back and after one circuit was cleared for the approach without the altitude restriction. I wrote an article on the incident and also brought it up at an FAA/Industry meeting that included Military representatives from the Navy. They said they would handle the situation. In effect, the controller wanted me to fly an unpublished leg that the avionics would not allow. (I did find a way that I could have followed the instructions by using the fly leg option with the leg specified as the one from the FAF to the runway, but in the heat of the moment, I did not think of it. Also ATC would have had to clear me to the lower altitude to make it feasible.)
arent Thames Radar doing those step downs to keep you in controlled airspace for as long as possible?
Thames do the vectoring (Biggin stipulate this on the ILS plate, presumably because they pay Thames a substantial (5-6 digit) annual sum for the radar service, so they want to get value for money) but IIRC it is below the base of the LTMA.
Remember also that an IMCR holder can legally fly into Biggin (Class D) but could not fly at all in Class A.
Biggin Hill ILS can be flown down to IAP MSA (it’s written in the plate) but I doubt the procedural version is available? except Saturday afternoon & Sunday morning? for the other days, one need Thames Radar to fly the ILS at Biggin, TR also manages London City arrivals, they do in & out of LTMA with vectoring at 3kft-5kft depending on traffic…
London City legacy DET/ALKIN arrival & ILS
I am not sure what arrangements between TR and EGLC & EGKB? but apparently these FSX/IVAO sim guys know what they are talking about, surely someone who knows his stuff
https://wiki.xu.ivao.aero/index.php?title=London_Terminal_Control_SE_DEPS
