Descent in the hold.

[whitehorse]

Having approached a beacon at say a MSA of 8,000ft when should the pilot descend to the minimum holding altitude of 3,000ft?
Is it,

1. as soon as you have passed over the beacon the first time, or
2. having passed the beacon the second time in the case of a parallel or off-set entry, ie not established in the hold.

Is it stated anywhere/does it matter?

[SkyCamMK]

If I understand you correctly then, when you are flying IFR and intend to use a beacon or other approach aid you will of course be in contact with ATC of some kind say approach control service or radar, If there is a level free at the beacon you would be so advised. How else could you separate yourself from other traffic in cloud over such a navigation or other beacon unless of course you were flying in VMC and even then there could be risks. In UK when I fly IFR I am kept clear of other known traffic by 4 nm laterally and 1000 ft clear above and below - this is a rule that is operated by the controlling ATC, Perhaps you could add some detail of how you come to ask the question so that we are clear - perhaps you have not studied IFR rules yet?

[whitehorse]

OK, I fly in a region where there is no ATC control, only Flight Information. The question I guess is when do the minimum hold altitudes apply. Is it as you go over the hold beacon for the first time as in a sector 1 and 2 joining the hold or must you be fully established in the hold before letting down.

[Duchess_Driver]

Situation also could arise when comms failed.

Fly as cleared or if not cleared, as filed......

[Spitoon]

Speaking as a simple controller, if I recall correctly, the 'terrain protected' area around a hold is for an aircraft established in the hold (i.e. over the beacon and turning onto the outbound leg) - so I wouldn't descend until that point. The protected area may be varied from the standard volume in a terrain rich environment by, for example varying the length of of the hold or the speed at which it is to be flown - so you would want to check such details before descending below MSA in IMC.

You mention 'letting down' in your post. No doubt you are aware of the legislation that SkyCamMK referred to - in the UK it is a bit complex but essentially to do an instrument approach without an ATC service is not permitted.

[richatom]

The question would only arise in the case of comms failure, when (if in IMC) you should follow your flight plan and not descend below MEA until you were in the hold pattern. In this situation, the question of whether you descend after the first pass of the beacon or the second is a little hypothetical frankly. OK, you could descend after the first pass as you are likely to be in the protected buffer zone of the hold pattern (unless wind is unkown and huge and you have not corrected for it). But most likely in IMC, with comms failure, and squaking 7600, you are not going to want to start descending until you are entirely sure that you are properly established in the hold and everybody below you knows it! I would fly at least a couple of holds at my filed en route altitude before daring to descend.

The question would not have arisen if you were in radio contact with ATC as you would have already requested and/or been cleared to descend to the lowest available hold altitude/level (above MSA) before arriving at the beacon.

[Tinstaafl]

Rules may vary across regions but in Oz you may descend immediately after crossing the aid for the first time ie starting the sector entry. Protected airspace for the hold entry is considered as part of the hold the design. I thought this was an ICAO spec.?


Just a point about something mentioned in one of the replies: There is no 'of course' with respect to instrument approaches being under the control of ATC nor for lots of other aspects of aviation for that matter. In many parts of the world instrument approaches may be done in non-controlled airspace. The pilots may receive a traffic information service - but not necessarily - and must themselves co-ordinate separation.

In the times I've moved countries I've had to unlearn quite a few 'of courses' - one which was 'of course' doing approaches sans ATC then discovering a requirement in my new country to have ATC services for the approach. And being able to fly IFR without an IR? That one was a real shock because 'of course' one must have an IR to fly IFR... :ooh:

[whitehorse]

Thanks TS. Anybody out there happen to know the ICAO reference he refers to, I don´t have the docs. with me at the moment. If not I will go through them when I get back to the UK. The internet is very slow/expensive here for me to search on line. Thanks for your replies.
WH

[Spitoon]

PANS-OPS is the reference, I think. Tinstaafl may be correct that the protected area includes the entry - it's a long time since I had to deal with all that stuff.

[LFS]

you can find a copy of pans-ops here http://dcaa.slv.dk:8000/icaodocs/ its doc 8168. All the information on protected areas for the hold etc are in there.

[SkyCamMK]

Thanks Tinstaafl - Oops, I should be less parochial, "of course"!!!

[bookworm]

PANS-OPS I 6 2.1 The holding area includes the basic holding area and the entry area. The basic holding area is the airspace required for a holding pattern at a specific level, based on the allowances for aircraft speed, wind effect, timing errors, holding fix characteristics, etc. The entry area is the airspace required for the entry procedure.

It goes on to describe the obstacle clearance above the "holding area" so defined.

[whitehorse]

Thanks everybody, I will look in doc 8168 on my return.
WH

[212man]

Clearly the entry must be protected, as it's acceptable to enter a hold at MHA. :ok: