Descent in hold

[mattpablo]

hello,

quick question

if I am established in the hold, holding at a minimum hold altitude of 6000 feet, and then cleared for the procedure,
if the IAF is an ‘AT’ 4900 feet, when can I descend out of 6000 to be established at 4900 at the required fix? Is it when you cross the beacon the hold is based on to go outbound in the hold again (which also coincides with the AT 4900 feet, and is the point at which the procedure goes outbound for a procedure turn to establish on the ILS)?

thanks

[aterpster]

ICAO identifier and specific IAP is necessary to answer such a question.

[mattpablo]

Thanks

an example would be XMN ZSAM, ILS 05 procedural, the min hold altitude is 1800 feet, IAF is 1500 feet, overhead the beacon which the hold is also based on, and point at which you go procedure outbound

if you were at 1800 and in turn outbound in hold, and cleared for approach, could you descend to 1500ft? (I realise you may not have to and could maintain 1800 ft in this procedure until crossing the beacon to go procedure outbound, I’m just asking legally when can you descend below min hold altitude)

thanks

[AerocatS2A]

I'd need to see a chart, but generally I don't see how you can descend below the holding altitude while still in the hold.

[SW1]

Youre cleared for the approach so exit the hold and cross the IAF(XLN) at the required 1500m. The MHA of 1800M only applies holding over XLN.

Also have a look at the missed approach( cant seem to paste the chart from jeppview on here). You can turn left to XLN and climb to 900m then "as directed"

The MHA keeps you clear of other traffic commencing over the vor at 1500m or traffic on the missed approach climbing to 900m.

MSA is 6300 feet in that quadrant. But is way beyond the holding area.

[aterpster]

Originally Posted by mattpablo

Thanks

an example would be XMN ZSAM, ILS 05 procedural, the min hold altitude is 1800 feet, IAF is 1500 feet, overhead the beacon which the hold is also based on, and point at which you go procedure outbound

if you were at 1800 and in turn outbound in hold, and cleared for approach, could you descend to 1500ft? (I realise you may not have to and could maintain 1800 ft in this procedure until crossing the beacon to go procedure outbound, I’m just asking legally when can you descend below min hold altitude)

thanks

It's 1,800 meters, not feet. I don't see where you are reading 1,500 meters. Attached is the Jeppesen chart for the Y ILS. (There is also a Z ILS, which requires RNAV.) If you are in the hold at XLN VOR at 5,910 feet (1,800 meters) once cleared for the approach you cannot descend below 5,910 until established on the 231 degree radial proceeding to XLN 7.3 DME. Once on the 231 radial you can descend to 2,960 feet (800 meters). You cannot go below 2,960 feet in the turn from the XLN 231 radial, 7.3 DME until rolling out on the localizer, at which time you can descend to 2,300 feet until intercepting the glideslope.

[SW1]

Originally Posted by aterpster

It's 1,800 meters, not feet. I don't see where you are reading 1,500 meters. Attached is the Jeppesen chart for the Y ILS. (There is also a Z ILS, which requires RNAV.) If you are in the hold at XLN VOR at 5,910 feet (1,800 meters) once cleared for the approach you cannot descend below 5,910 until established on the 231 degree radial proceeding to XLN 7.3 DME. Once on the 231 radial you can descend to 2,960 feet (800 meters). You cannot go below 2,960 feet in the turn from the XLN 231 radial, 7.3 DME until rolling out on the localizer, at which time you can descend to 2,300 feet until intercepting the glideslope.

its 1500m(4930 feet) at XLN for the IAF

[aterpster]

Originally Posted by SW1

its 1500m(4930 feet) at XLN for the IAF

I missed that. That is an unusual way of showing it. So, cleared for the approach in the holding pattern, a descent to 4,930 could be started once inbound on the 050 radial.

[AerocatS2A]

I wonder if ATC would just clear you to 1500m when they clear you for the approach.

[mattpablo]

Thanks for the the replies

it’s my understanding, as some have mentioned, that once cleared for the approach, you can descend to the IAF altitude, as the min hold altitude is only related to aircraft seperation and not terrain clearance, and therefore even if you are on the outbound leg of the hold (tracking 050) you could descend, (you do not have to be inbound to the beacon).

thanks

[SW1]

Thats correct Matt.

Although if youre outbound in the hold and atc clears you for the approach- immediate exit on the mcdu and the aircraft starts a left turn back to XLN. No need to waste time finishing off the hold- youre still in the protected area of the hold and that particular MHA is not due to terrain clearance.

You can even start that 1000 foot descent to 4930 whilst turning to comply with the altitude constraint.

Cheers

[SW1]

Originally Posted by AerocatS2A

I wonder if ATC would just clear you to 1500m when they clear you for the approach.

Its China remember. Once cleared for the approach its up to you to comply with the charted altitudes.

[aterpster]

Originally Posted by SW1

Its China remember. Once cleared for the approach its up to you to comply with the charted altitudes.

I don't know of anywhere where it is okay to descend below the MHA until inbound to the holding fix on course. Sure, terrain clearance isn't an issue at this location, but it is nonetheless the charted minimum holding altitude.

[SW1]

Aterpster. Agree with you partially but have a look at ILS Y 36L ZSSS its almost identical.

Yes you can continue in the hold and start your descent inbound to the fix.

This MHA is due to TRAFFIC. if youre outbound then its another 3 or so minutes before you cross XLN. ATC would be giving you a "direct XLN" (curtly) if you request to continue on the "published hold" until tracking inbound 050 radial. Hence my china comment. You are under radar control as well might I add.

Youre not the only traffic around going into Xiamen so he wants you on the procedure for his sequencing.

[aterpster]

Originally Posted by SW1

Aterpster. Agree with you partially but have a look at ILS Y 36L ZSSS its almost identical.

Yes you can continue in the hold and start your descent inbound to the fix.

This MHA is due to TRAFFIC. if youre outbound then its another 3 or so minutes before you cross XLN. ATC would be giving you a "direct XLN" (curtly) if you request to continue on the "published hold" until tracking inbound 050 radial. Hence my china comment. You are under radar control as well might I add.

Youre not the only traffic around going into Xiamen so he wants you on the procedure for his sequencing.

I agree that I should turn inbound to XLN upon receiving the approach clearance but I still wouldn't leave 5,910 until established inbound on the 050 radial unless ATC said "descend to my radar altitude of 1,500 meters now."

As to ZSSS ILS Y 36L If I were parked in the hold at 3,940 and cleared for the approach, I would turn inbound in the hold immediately but not leave 3,940 for 2,960 until inbound on the JTN 181 radial or inbound on the ISH Localizer.

[SW1]

Originally Posted by aterpster

I agree that I should turn inbound to XLN upon receiving the approach clearance but I still wouldn't leave 5,910 until established inbound on the 050 radial unless ATC said "descend to my radar altitude of 1,500 meters now."

As to ZSSS ILS Y 36L If I were parked in the hold at 3,940 and cleared for the approach, I would turn inbound in the hold immediately but not leave 3,940 for 2,960 until inbound on the JTN 181 radial or inbound on the ISH Localizer.

where you should be at 550m (1810) youre just setting yourself up for glideslope from above( youll be going around by the way) you have 2 miles to descend from 3940 to 1800 feet, Please read the chart- that seems an issue that youre dead set on complying with the MHA even though its going to cause you some BIG problems)

At JTN your altitude check is 1280 feet on the glideslope. inbound localiser established.

can you post the chart so at least the rest of audience can see what youre implying? I cant paste it - so its difficult to prove my point of view

[aterpster]

Originally Posted by SW1

where you should be at 550m (1810) youre just setting yourself up for glideslope from above. you have 2 miles to descend from 3940 to 1800 feet, Please read the chart. At JTN your altitude check is 1280 feet on the glideslope. inbound localiser established.

can you post the chart so at least the rest of audience can see what youre implying? I cant so difficult to prove my point of view

I am under the impression I have to do the racetrack 4.4 JTN DME initial approach segment after leaving the hold. (bold planview track vs thin planview track.)Then again, I am not qualified in things Chinese, so I would certainly want an expert Chinese flight ops class before tackling a procedure like the ZSSS ILS DME Y Runway 36. (or for anywhere in that part of the world.)

[SW1]

Originally Posted by aterpster

I am under the impression I have to do the racetrack 4.4 JTN DME initial approach segment after leaving the hold. (bold planview track vs thin planview track.)Then again, I am not qualified in things Chinese, so I would certainly want an expert Chinese flight ops class before tackling a procedure like the ZSSS ILS DME Y Runway 36. (or for anywhere in that part of the world.)

There you go. I answered matts question with Chinese experience.

[aterpster]

Originally Posted by SW1

There you go. I answered matts question with Chinese experience.

All the other nuances aside I can't imagine departing the MHA of a holding pattern for a lower inbound altitude anywhere in the world.

[SW1]

Originally Posted by aterpster

All the other nuances aside I can't imagine departing the MHA of a holding pattern for a lower inbound altitude anywhere in the world.

As said these MHAs are for traffic only- and this is how they do things in China. Most of the IAFs around ZSAM has the 5910 restriction as the guys going direct are cleared to commence at 4940 feet.

Know the environment before commenting. The OP was asking for advice. By the way if you "stuck to you your guns" regarding that MHA and messed up the approach on a PC you would fail(shanghai case)

How they do things stateside doesnt count. I wouldnt comment on a SFO approach when ive never been there.

BTW: Matt should have posted this to the fragrant harbour forum- as at least the dragon and cathay guys could give some input as they fly to both destinations.

cheers