pilots discretion

pc12_driver

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just another "senior moment" but here goes:

Cruising at FL280, ATC gives ' descend pilots discretion to FL180'. What do the regs say?

Please don't flame to hard!!
 

bluelake

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I dont think any FAR is applicable, at least one that comes to mind. The Pilot Controller Glossary says this..

"When used in conjunction with altitude assignments, means that ATC has offered the pilot the option of starting climb or descent whenever he wishes and conducting the climb or descent at any rate he wishes. He may temporarily level off at any intermediate altitude. However, once he has vacated an altitude, he may not return to that altitude."
 

DC8 Flyer

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Ahh, the hell with it. Trying to have a discussion anymore is like winning the special olympics.
 
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Pedro

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DC8 Flyer said:
Also keep in mind, from the point of the "PD" to the "assigned" altitude, may not give you adequete terrain clearance.
That's interesting, got a link? Notflaming, reallywant to know.
 

satpak77

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DC8 Flyer said:
Also keep in mind, from the point of the "PD" to the "assigned" altitude, may not give you adequete terrain clearance.
ATC would not give this clearance if it did not provide terrain clearance

you are still under IFR handling. Traffic and Terrain (TNT) is ATCs responsibility under IFR, its all yours under VFR. Of course we have a obvious responsibility to back up and verify ATC and maintain an awareness of terrain at all times.

"IFR" and "VFR" concern HANDLING. IMC and VMC concern actual visual conditions.

The question was not "maintain VMC conditions and decend to XXXX altitude" or "November XXX, are you able to maintain terrain clearance visually?", it was PD to XXX altitude. XXX Altitude would be at or above the MVA, MSA, or MEA that applies in the area.
 
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avbug

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Also keep in mind, from the point of the "PD" to the "assigned" altitude, may not give you adequete terrain clearance.
If ATC provides the clearance "Descend and maintain Flight Level 180," you have adequate terrain separation down to Flight Level 180.

If ATC provides the clearance, "Pilots Discretion, descend and maintain flight level 180," you have adequate terrain separation down to Flight Level 180.

What's the difference with respect to terrain separation and the clearance? There isn't any.

If ATC tells you to maintain your own terrain separation, that's another matter entirely.

FAA Order 7110.65P:

4-5-7. ALTITUDE INFORMATION
Issue altitude instructions as follows:

d. A specified altitude over a specified fix for that portion of a descent clearance where descent at pilot's discretion is permissible. At any other time it is practicable, authorize climb/descent at pilot's discretion.

PHRASEOLOGY-
CLIMB/DESCEND AT PILOT'S DISCRETION.

EXAMPLE-
"United Four Seventeen, descend and maintain six thousand."

NOTE-
The pilot is expected to commence descent upon receipt of the clearance and to descend at the suggested rates specified in the AIM, para 4-4-9, Adherence to Clearance, until reaching the assigned altitude of 6,000 feet.

EXAMPLE-
"United Four Seventeen, descend at pilot's discretion, maintain six thousand."

NOTE-
The pilot is authorized to conduct descent within the context of the term "at pilot's discretion" as described in the AIM.

EXAMPLE-
"United Four Seventeen cross Lakeview V-O-R at or above flight level two zero zero, descend and maintain six thousand."

NOTE-
The pilot is authorized to conduct descent "at pilot's discretion" until reaching Lakeview VOR. The pilot must comply with the clearance provision to cross the Lakeview VOR at or above FL 200, and after passing Lakeview VOR, the pilot is expected to descend at the rates specified in the AIM until reaching the assigned altitude of 6,000 feet.

EXAMPLE-
"United Four Seventeen, cross Lakeview V-O-R at and maintain six thousand."

NOTE-
The pilot is authorized to conduct descent "at pilot's discretion," but must comply with the clearance provision to cross Lakeview VOR at 6,000 feet.

EXAMPLE-
"United Four Seventeen, descend now to flight level two seven zero, cross Lakeview V-O-R at or below one zero thousand, descend and maintain six thousand."

NOTE-
The pilot is expected to promptly execute and complete descent to FL 270 upon receipt of the clearance. After reaching FL 270, the pilot is authorized to descend "at pilot's discretion" until reaching Lakeview VOR. The pilot must comply with the clearance provision to cross Lakeview VOR at or below 10,000 feet. After Lakeview VOR, the pilot is expected to descend at the rates specified in the AIM until reaching 6,000 feet.

NOTE-
1. A descent clearance which specifies a crossing altitude authorizes descent at pilot's discretion for that portion of the flight to which the crossing altitude restriction applies.
2. Any other time that authorization to descend at pilot's discretion is intended, it must be specifically stated by the controller.
3. The pilot may need to know of any future restrictions that might affect the descent, including those that may be issued in another sector, in order to properly plan a descent at pilot's discretion.
4. Controllers need to be aware that the descent rates in the AIM are only suggested and aircraft will not always descend at those rates.


REFERENCE-
P/CG Term- Pilot's Discretion.

e. When a portion of a climb/descent may be authorized at the pilot's discretion, specify the altitude the aircraft must climb/descend to followed by the altitude to maintain at the pilot's discretion.

PHRASEOLOGY-
CLIMB/DESCEND NOW TO (altitude), THEN CLIMB/DESCEND AT PILOT'S DISCRETION MAINTAIN (altitude).

EXAMPLE-
"United Three Ten, descend now to flight level two eight zero, then descend at pilot's discretion maintain flight level two four zero."

NOTE-
1. The pilot is expected to commence descent upon receipt of the clearance and to descend at the suggested rates specified in the AIM, para 4-4-9, Adherence to Clearance, until reaching FL 280. At that point, the pilot is authorized to continue descent to FL 240 within the context of the term "at pilot's discretion" as described in the AIM.
2. Controllers need to be aware that the descent rates in the AIM are only suggested and aircraft will not always descend at those rates.


f. When the "pilot's discretion" portion of a climb/descent clearance is being canceled by assigning a new altitude, inform the pilot that the new altitude is an "amended altitude."

EXAMPLE-
"American Eighty Three, amend altitude, descend and maintain Flight Level two six zero."

NOTE-
American Eighty Three, at FL 280, has been cleared to descend at pilot's discretion to FL 240. Subsequently, the altitude assignment is changed to FL 260. Therefore, pilot's discretion is no longer authorized.

PILOT'S DISCRETION - When used in conjunction with altitude assignments, means that ATC has offered the pilot the option of starting climb or descent whenever he/she wishes and conducting the climb or descent at any rate he/she wishes. He/she may temporarily level off at any intermediate altitude. However, once he/she has vacated an altitude, he/she may not return to that altitude.
 

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.......
 
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172driver

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they cleared us to descend at pilot's discretion for a visual approach.
I don't think this is the same scenario we were talking about, in which a PD descent to a specific (safe) altitude is given. Obviously, once cleared for a visual approach, it's your baby.
 

minitour

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172driver said:
I don't think this is the same scenario we were talking about, in which a PD descent to a specific (safe) altitude is given. Obviously, once cleared for a visual approach, it's your baby.
Yeah a visual is a bit different. Just last night we had the field in sight from 20 miles out at 5000' and were cleared for the visual approach...would it make sense to start down at 500fpm? Hardly...there's no "guarantee" of terrain clearance there.

-mini
 

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avbug

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Yeah a visual is a bit different. Just last night we had the field in sight from 20 miles out at 5000' and were cleared for the visual approach...would it make sense to start down at 500fpm? Hardly...there's no "guarantee" of terrain clearance there.
Nor is there intended to be. Hence the concept of the visual clearance. You have the runway environment in sight, or the preceeding aircraft, and altitude is your discretion in reaching the runway. This is not at all the same as the PD disretion descent under discussion in this thread.

A visual descent requires that you maintain your own terrain and obstacle separation, your own cloud clearance, etc. A PD clearance to descend to a specific lower altitude, however, is predicated on standard terrain separation for the sector being flown. A PD descent is no different in terms of terrain separation than a descent clearance without pilot discretion.

Knowledge tells me PD keeps me away from the terrain, wisdom tells me a PD could put me into terrain if I dont keep track of where Im at.
Wisdom should be telling you that a descent could put you into terrain any place, anywhere, if you don't keep track of where you are, regardless of weather it's part of a clearance, proceedure, etc. Following false glideslope signals, responding inadvertantly to another aircraft's clearance, which is sharing a similiar callsign, mistaking your location, etc, can all result in controlled flight into terrain, regardless of the type of descent clearance.

Even so, if we were to take AB's version of a PD, ATC could give me a PD to anything, visual, altitude, etc, and I would have terrain clearance.
I said no such thing. You're mixing apples with oranges with pineapples. You needn't take "AB's version," but you should take the FAA's version, which is what I posted from the controller's handbook, verbatim.

An enroute PD descent clearance differs in no wise from a standard descent clearance. You should keep track of your position at all times, regardless of weather the words "PD" are used, or not. However, a PD descent doesn't place the responsibility of terrain avoidance or your own safety on you to any greater degree than a standard descent clearance.

There's no such thing as a pilots discretion descent to a visual. You may have a pilot's discretion descent to a particular altitude, and will be cleared for a visual once you have reported the field in sight, but ATC isn't going to clear you for that visual until you've reported the field in sight or the preceeding aircraft. At that point, once you've accepted that clearance, you're responsible for your own descent and terrain separation...you're no longer on an instrument descent, but a visual descent, which requires looking outside the cockpit. While the visual approach clearance is an IFR clearance, obstacle protection and terrain and obstruction clearance if your problem and your responsiblity. Not at all the same as an enroute descent clearance.

In theory, ATC could descend you into terrain at any time. Face it, much of the time you really have no idea what exactly your proximity to this hill or that rock is while IMC. Especially on vecors, while working close to the MVA. You can't look up the MVA, you have to trust the controller to put you at the minimum vectoring altitude, which is often the case while being set up for vectors to an approach.

Once you've been given a descent to a lower altitude, you're good down to that altitude. Weather the controller tells you that you can get there at your own pace (eg, Pilot's Discretion), or merely instructs you to "descend and maintain," the obstacle and clearance protection remains the same.

So a PD to an altitude should always take into account whats in front of you. Should you do that with any ATC altitude assignment, of course, but I feel PDs require more dilligence, especially in this day and age of slang and shortcuts, PD could be used in an inappropriate place.
Only if one might presume that there is any difference in the methodology used to determine when an aircraft can descend, between a standard "descend and maintain" clearance and one given at pilot's discretion...there is no difference in terms of when a controller will give that clearance.

The former, "descend and maintain" indicates that you are to begin your descent now, and that you are good down to xxx altitude.

The latter, "Pilot's Discretion," indicates that you can begin your descent when you like, starting now, and that you are good down to xxx altitude.
 

Vector4fun

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I still see crews who, at night, descend right on down to the FAF altitude when cleard for a Visual. (I'm talking 10-20 miles out) That may be fine when you know the area and have great vis with all the terrain, but I've given more than a few no-sh!t low altitude warnings where the hills didn't have any lights on them. Just something to be aware of....
 

minitour

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avbug said:
Nor is there intended to be. Hence the concept of the visual clearance. You have the runway environment in sight, or the preceeding aircraft, and altitude is your discretion in reaching the runway. This is not at all the same as the PD disretion descent under discussion in this thread.

A visual descent requires that you maintain your own terrain and obstacle separation, your own cloud clearance, etc. A PD clearance to descend to a specific lower altitude, however, is predicated on standard terrain separation for the sector being flown. A PD descent is no different in terms of terrain separation than a descent clearance without pilot discretion.
Correct, but if you're given "Descend PD for the Visual to 4L" (as was quoted in the post before mine), they aren't giving you a specific altitude. So you need to watch below. Still a PD clearance...but don't go dragging the prop in because you can...as Vector said, there may be hills out there without lights on them.

-mini

-mini
 

avbug

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Pilots are still responsible for staying above the minimum IFR altitudes until reaching that FAF. Lacking a controller that provides a MVA for pilot reference, the pilot must remain above published altitudes applicable to his or her routing.

That much is basic.

However, show me a clearance that reads "Pd to the visual." The quote in the post before yours, to which you refer, is incorrect. ATC would have provided a pilot discretion descent to xxx altitude, and then cleared the pilot for a visual after that. A PD descent to a visual is nonsensical, unless the pilot already has the field in sight (or the preceeding aircraft), in which case the controller still doesn't say "Pd to the visual," but merely clears the pilot for a visual. Once cleared for the visual, the pilot is responsible for maintaining his or her own terrain separation.
 

Lead Sled

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avbug said:
Pilots are still responsible for staying above the minimum IFR altitudes until reaching that FAF...ATC would have provided a pilot discretion descent to xxx altitude, and then cleared the pilot for a visual after that. A PD descent to a visual is nonsensical, unless the pilot already has the field in sight (or the preceding aircraft), in which case the controller still doesn't say "Pd to the visual," but merely clears the pilot for a visual. Once cleared for the visual, the pilot is responsible for maintaining his or her own terrain separation.
You can get a Cruise Clearance which is essentially a DP descent followed by an approach of your choice.

The basic problem with all of this "Pilot's Discretion" stuff is that I have been hanging around pilots for 40 years and not one of them has any discretion at all. :0

'Sled
 

minitour

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Lead Sled said:
The basic problem with all of this "Pilot's Discretion" stuff is that I have been hanging around pilots for 40 years and not one of them has any discretion at all. :0

'Sled
*rimshot*
Folks, he'll be here all week! Try the roast beef!

-mini

*edit*
PS. Avbug, I see what you mean and yeah...that makes more sense. I guess "Descent pilot's discretion for the Visual approach to runway 4" wouldn't be smart.

You could, however, get "Descent PD to 3,000, upon reaching 3000 cleared visual approach runway 4"...but again, he/she is giving you terrain/obstruction clearance down to 3000'. Once you get there (since you already have the field in sight), it's your job to watch for rocks and "pilot skewers" (antennas) below.

Good call avbug.
 
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172driver

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The quote you refer to as incorrect came directly from the article that was posted. The quote is, in fact, correct, though the clearance most certainly is not. Either it was inappropriately casual or the pilot writing the article quoted it incorrectly.
 

DC8 Flyer

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172driver said:
The quote you refer to as incorrect came directly from the article that was posted. The quote is, in fact, correct, though the clearance most certainly is not. Either it was inappropriately casual or the pilot writing the article quoted it incorrectly.
Thank you! Someone that can read and understand!
 

Vector4fun

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A visual approach is a discretionary descent. The pilot may descend at whatever time and rate he/she thinks appropriate for approach and landing. If a pilot reports leaving 4000' on a visual approach, ATC cannot then immediately assign 4000' to an aircraft above without insuring some other form of separation. I have, in fact, used the phraseology;

"Descend now to 3000', then cleared visual approach rwy XX"

To insure a descent at standard rates to 3000' before the discretionary descent begins. That said, once cleared for a visual, the crew is primarily responsible for maintaining a safe altitude above terrain. ATC's only responsibility is, of course, safety alerts if we are aware the aircraft is below a safe altitude. I emphasize that, because ATC may very well NOT be aware if you are outside or below radar coverage.

I *might* use an altitude restriction in conjunction with a visual approach clearance to insure separation from another aircraft. For example:

"Maintain 3000' till established on final, cleared visual approach".

That's to keep the aircraft separated from another below, that the crew doesn't see. Doesn't have anything to do with terrain.
 
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