Enroute Holding
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Joined: Apr 2005
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From: Anchorage
Enroute Holding
What appeared to be a simple request has turned into a serious discussion, can anyone clarrify.
The other day when approaching Chicago (ORD) we were given holding instructions due to congestion, and they were as follows
“Hold North on the 360 Radial from MSN at FL210, 15 NM legs approved, and own speed”
My question is, does this mean that the inbound leg can be up to 15NM, or does it mean that an inbound turn must be commenced at 15NM from MSN when on the outbound leg?
Bear in mind that at 280 KTS after turning outbound and abeam MSN outbound we were at 9NM already
The other day when approaching Chicago (ORD) we were given holding instructions due to congestion, and they were as follows
“Hold North on the 360 Radial from MSN at FL210, 15 NM legs approved, and own speed”
My question is, does this mean that the inbound leg can be up to 15NM, or does it mean that an inbound turn must be commenced at 15NM from MSN when on the outbound leg?
Bear in mind that at 280 KTS after turning outbound and abeam MSN outbound we were at 9NM already
Thread Starter
Joined: Apr 2005
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From: Anchorage
I don't think so as the speed was our request, I am looking for clarity on the 15nm, if it is the leg distance as given, or is it as depicted in the jepp atc section which shows a turn at 15 dme
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From: Mostly FL360-380, M0.78
I would think you should hold as they say .. north of MSN on the 360-R using 15 nm legs at your own speed.. meaning you should start your turn at 15 nm on your outbound leg and can use the speed of your liking.
ICAO DOC 8168
1.3.5 Outbound leg length based on a DME distance
If the outbound leg length is based on a DME distance, then the outbound leg terminates as soon as the limiting DME distance is reached.
http://dcaa.slv.dk:8000/icaodocs/Doc%208168/8168_v1.pdf
ICAO DOC 8168
1.3.5 Outbound leg length based on a DME distance
If the outbound leg length is based on a DME distance, then the outbound leg terminates as soon as the limiting DME distance is reached.
http://dcaa.slv.dk:8000/icaodocs/Doc%208168/8168_v1.pdf
Last edited by Jetavia; 12th October 2005 at 00:13.
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From: Dre's mum's house
Interesting.
I would have said that putting a 15nm leg in to the computer would have resulted in the outbound commencing from wings level i.e at completion of the turn, and terminating 15nms later.
I would have said that putting a 15nm leg in to the computer would have resulted in the outbound commencing from wings level i.e at completion of the turn, and terminating 15nms later.
Thread Starter
Joined: Apr 2005
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From: Anchorage
Jetavia, as a matter of interest in the USA timing is based on the inbound leg and not the outbound as the rest of the world. However as I see it normally a leg distance can be given, or requested to avoid all the turning of a standard holding pattern which would be 1.5 minutes at FL250.
In this case if we had turned inbound at 15nm, our outbound leg would have been only 46sec with the prevailling winds. This is more restrictive than the standard 1.5 min, and I don't think this was the intention of ATC.
However I may be misinterperiting the request
In this case if we had turned inbound at 15nm, our outbound leg would have been only 46sec with the prevailling winds. This is more restrictive than the standard 1.5 min, and I don't think this was the intention of ATC.
However I may be misinterperiting the request
Joined: Dec 2001
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From: Mostly FL360-380, M0.78
Thunder .. maybe the answer to your Q can be found in the US AIM http://www.faa.gov/ATpubs/AIM/Chap5/aim0503.html#5-3-7
Joined: Jun 2005
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From: USA
ThunderSkye,
It appears that the answer is in fact contained within the AIM. (thanks, Jetavia) It looks like when you are flying the hold by reference to DME or RNAV, as in a defined leg-length hold, it is the outbound leg that is measured and defines the point where the inbound turn is commenced. Only on timed holds is the length (elapsed time) of the outbound leg adjusted so as to cause the inbound leg to last the appropriate length of time.
Thanks for sharing this one, Thunder. Since I have a trip to Chi-town later this week, it probably means I'll get assigned a hold too! At least I've now had a refresher on what to do when I get it. Thanks, buddy!
Best regards,
Westhawk
It appears that the answer is in fact contained within the AIM. (thanks, Jetavia) It looks like when you are flying the hold by reference to DME or RNAV, as in a defined leg-length hold, it is the outbound leg that is measured and defines the point where the inbound turn is commenced. Only on timed holds is the length (elapsed time) of the outbound leg adjusted so as to cause the inbound leg to last the appropriate length of time.
Thanks for sharing this one, Thunder. Since I have a trip to Chi-town later this week, it probably means I'll get assigned a hold too! At least I've now had a refresher on what to do when I get it. Thanks, buddy!
Best regards,
Westhawk
Joined: Sep 2000
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From: min rest
Enroute high altitude holds......consider your speed.....slowing up in a heavy L1011 to hold enroute not followed by a descent resulted in not being able to accelerate to cruise speed in level flight with MCT set for one of our crews.
Skyhawk...If confused in future by such clearences....We would suggest you ask ATC to..."Say again "fully"xxx ATC hold instructions"
This revealed one sim instructor who had no knowledge of how he should issue correctly and in the correct sequence an ATC hold instruction. He was alwys confuseing his crews under check in exactly the same way as you were.
Skyhawk...If confused in future by such clearences....We would suggest you ask ATC to..."Say again "fully"xxx ATC hold instructions"
This revealed one sim instructor who had no knowledge of how he should issue correctly and in the correct sequence an ATC hold instruction. He was alwys confuseing his crews under check in exactly the same way as you were.
Last edited by scanscanscan; 13th October 2005 at 15:30.
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Scan,
I question why your L1011 crew would have had difficulty accelerating from holding speed. Seeing as the intent of holding speed is to provide the least fuel flow, while still allowing enough of a margin for control and pilot technique issues, this also means minimum drag speed, or close to it. Ergo, minimum thrust required, and therefore near the maximum excess thrust available. So holding speed should give you very close to the best acceleration possible once you decide to resume cruise.
Hawk
I question why your L1011 crew would have had difficulty accelerating from holding speed. Seeing as the intent of holding speed is to provide the least fuel flow, while still allowing enough of a margin for control and pilot technique issues, this also means minimum drag speed, or close to it. Ergo, minimum thrust required, and therefore near the maximum excess thrust available. So holding speed should give you very close to the best acceleration possible once you decide to resume cruise.
Hawk
Joined: Sep 2000
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From: min rest
The manual after this incident now says minimum holding speed at high altitude (possibly means optimin altitude for weight) for the L1011 is LRC unless immediately followed by a descent.
Hopefully 411A can comment and set the record straight.
Hopefully 411A can comment and set the record straight.
Joined: Mar 2000
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From: Arizona USA
Scanscanscan is spot on.
Minimum holding speed at high altitude in the Lockheed tri-motor is indeed LRC.
As the L10 has a true high-speed laminar flow wing, any slower is just asking for trouble, especially in -22B powered models.
I was once asked by London control to hold at 210KIAS at FL370.
Quite frankly, they really had positively no idea about jet transport aircraft performance at higher altitudes...then.
I wonder if it has improved?
Minimum holding speed at high altitude in the Lockheed tri-motor is indeed LRC.
As the L10 has a true high-speed laminar flow wing, any slower is just asking for trouble, especially in -22B powered models.
I was once asked by London control to hold at 210KIAS at FL370.
Quite frankly, they really had positively no idea about jet transport aircraft performance at higher altitudes...then.
I wonder if it has improved?
