Descend at your Discretion

AU_James

AU_James

Pre-takeoff checklist
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Display name:
James
So I'm a low time pilot and went on my first real cross country trip a couple weeks after getting my ticket with my fiancé. We're heading back home, I picked up flight following for the ~2 hr flight heading west at 6,500 in a club Cherokee 160. I get my last handoff and it's at night so I think I'll cancel flight following when I'm 100% comfortable with the lights near/around my home airport.

I'm traveling at about 100kts due to winds, traffic pattern altitude is 2,000' and I'm at 6,500' so I do some quick calculations and decide it'll take me about 15nm to descend and I want to arrive at TPA a few miles from the airport, so call it 20nm out to start my descent.

At about 35nm from the destination airport I hear, "Cherokee 123AB descend at your discretion." I reply, "Approach, 123AB, descend at discretion" and I continue flying at 6,500' because I still have a few mins before my planned descent. Roughly 3 minutes later (~5nm) I hear, "Cherokee 123AB descend at your discretion." I reply, "Approach, 123AB, will descend shortly at my discretion."

I wait anther few minutes, reduce power and descend nice and slowly/smoothly (this is only the second leg of my fiancé's first cross country), cancel flight following as I identify the airport, arrive at TPA a few miles from the airport where I've already turned the lights on, and make a decent night landing (her first) considering I just did 5-6 night landings the previous week at an airport nearby just in case we ended up coming back at night on this trip.

My question is why the controller repeated their communication when I definitely read it back and understood that I didn't need to tell them when I was descending? Sure, they could have missed my reply but we had no communication issues so far and there was some time between their transmissions. It made me feel like they were suggesting I begin my descent already but I was very assured in my plan. I also didn't want to get too low too early at night. I followed my plan and everything went well, but I'm just not sure of the intent behind the controllers repeated communication with me to descend.

Ultimately, no big deal at all, just looking for thoughts?

PS- this was also the first time the fiancé helped secure and tie down the plane, just to get her in the habit ;)
 
My .02, especially flying at night, stay high as long as possible even if you have to circle at your destination. Saved me once.

Not sure why he repeated his call to you, sounds like you did fine.


Sent from my iPhone using Tapatalk
 
Controllers sometimes say things as prompts when more direct phraseology would be more appropriate. You are correct. The controller left it COMPLETELY up to you by giving you pilot's discretion. There's two possible reasons he repeated himself. The first is that he may have thought you didn't realize that you have his permission (blessing is a better word unless he stuck you at a hard altitude) to start down and he felt he needed to make sure you understood the descent at PD.

The second and more likely is that he really didn't mean what he said. What he may have wanted to get across is something to this effect..."N1AB, start the descent now", or something else. Who knows. Controllers use DPD so much that it becomes habit and isn't the most descriptive instruction for what they intend for you to do.

For example, I catch myself saying DPD sometimes as I drive an inbound into a gaggle of planes being sequenced with 10 or more airplanes within 15 miles of the field. I don't really mean to say that. What I MEAN to do is to manually fly that airplane, vector by vector and altitude by altitude and PLACE that airplane WHERE I NEED HIM TO BE. Something that DPD doesn't always accomplish. Many times the DPD is quickly followed by some other more specific instruction and probably should have been given in the first place to accomplish the controller's intent.

It's hard to say without knowing the big flick.

tex
 
The repeat is often controller speak for start descending to help me out with approaching IFR traffic. You are still free to fly where you want but this is where communication helps. Once he says "descend at your discretion" and you acknowledge without further stating your intentions, he is really expecting you to start down.

I get this all the time as well...and I have had also times that I wanted to stay high for whatever reason. My response is on the initial call up is "roger, gonna stay here for a few miles unless you need me lower". That way he knows my intentions and I give him the ability if me changing that helps him which I am often willing to oblige by.
 
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Yeah and when IFR in VFR conditions they ask if you "see the airport" and if you say negative they sometimes get irritated. I know why. The big iron can see if from there (because they are higher) and they want you to cancel IFR.
 
Excellent post because this is something I have dealt with many times, except the opposite: it's daytime and they never 'sign off'.

Example: I'm 10nm from my destination at 7500' and I'm still waiting for them to say something like "okay you're airport is 10 miles in front of you and there's no traffic so squawk 1200 have a nice day". That never comes and I'm way way over the top of my destination airport when I should have descended long ago.

This happens pretty much every time I get FF. I guess I'm supposed to just tell them "Approach/Center, 27161 has airport in site" but I'm worried they're too busy to hear such babble...
 
pkuhns said:
I guess I'm supposed to just tell them "Approach/Center, 27161 has airport in site" but I'm worried they're too busy to hear such babble...
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100% correct radio call.

"Approach, Skyhawk 12345, Airport in sight" is perfectly acceptable and polite pilot speak for either "hey dumbass, you may have forgotten about me, is handoff to tower coming?" or "I want a frequency change to CTAF"

And you should never be stuck too high just cuz you are on FF and can't get a word in. You are not IFR subject to their restrictions where ATC dictates the altitudes. You are free to fly at what altitude you what and start down whenever you want absent any attitude restrictions issued by ATC.

AIM says that pilots should advise ATC of altitude changes..."should", not "must" and "advise", not "request".

"Approach, Skyhawk 12345 starting VFR decent into Watsonville" is all you need. If you can't get a word in edge wise...just start down whenever you need.
 
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pkuhns said:
Excellent post because this is something I have dealt with many times, except the opposite: it's daytime and they never 'sign off'.

Example: I'm 10nm from my destination at 7500' and I'm still waiting for them to say something like "okay you're airport is 10 miles in front of you and there's no traffic so squawk 1200 have a nice day". That never comes and I'm way way over the top of my destination airport when I should have descended long ago.

This happens pretty much every time I get FF. I guess I'm supposed to just tell them "Approach/Center, 27161 has airport in site" but I'm worried they're too busy to hear such babble...
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Just remind them. They sometimes forget. Don't wait until your on top of the field.
 
Try
"We have to get down to the airport now"
or
"If we don't descend now, we are going to exceed our maximum descent rate profile"
 
coloradobluesky said:
Try
"We have to get down to the airport now"
or
"If we don't descend now, we are going to exceed our maximum descent rate profile"
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Airport in sight works just fine with many fewer words. So does just descending, with or without advising, as long as you haven't been restricted. This is VFR.

Occasionally, restrictions happen. I've arrived at Fresno before restricted above 2500 into downwind. There was a good reason for it -- maximum departing traffic on both runways.
 
coloradobluesky said:
Try
"We have to get down to the airport now"
or
"If we don't descend now, we are going to exceed our maximum descent rate profile"
Click to expand...

If you are on FF, both of those calls are request asking for permission to descend which is not needed VFR (absent attitude restrictions).

If your call regarding altitude changes requires ANYTHING other than a response of "Thank You" by ATC you have actually made a "Request" needing a response with another readback and have not simply "Advised"...thus probably resulted in a crabby controller.
 
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When I'm changing altitude on VFR FF I always advise them and usually here something like "N123 remain VFR" which I assume means HUA!

I tell them so they know my intentions. I like having a controller on my team.
 
Dave S. said:
more likely is that he really didn't mean what he said. What he may have wanted to get across is something to this effect..."N1AB, start the descent now", or something else. Who knows. Controllers use DPD so much that it becomes habit and isn't the most descriptive instruction for what they intend for you to do.
Click to expand...

Shawn said:
The repeat is often controller speak for start descending to help me out with approaching IFR traffic.
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Ah, these are the insights I was looking for!

My only reason to stay there longer was that it was at night and I didn't want to descend before *I* needed to. With that being said, I would have been perfectly willing and comfortable going a bit lower for a few miles since I was near my home airport and knew there were no tall towers or obstructions for me to worry about. I'm 100% about making a controllers job easier if it's of no real consequence to me and safety, I just don't have the experience to pick up on what they were laying down.

pkuhns said:
That never comes and I'm way way over the top of my destination airport when I should have descended long ago.
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I DID know that for one, I can always say "Approach, Cherokee 12345, request frequency change to Airport Tower." or "...airport in sight, request cancel flight following." or "beginning VFR descent to Airport." Flight following is a two-way street in that not only does it give another set of eyes to help you, but it also gives the controllers a heads up on where you are and what you're doing which makes everybody more safe. If you told them you're going Airport X and then they look down and you're right on top of Airport X at 7,500' they now have a bigger headache than if you just told them you're descending.

Thanks for the discussion!
 
pkuhns said:
Excellent post because this is something I have dealt with many times, except the opposite: it's daytime and they never 'sign off'.

Example: I'm 10nm from my destination at 7500' and I'm still waiting ...
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As stated earlier "Airport in site" or "Request frequency change" works ... unless you're in my area (see below):mad:

My field is on the west side of El Paso with the mountain between my field and the main Class C (KELP). If departing eastbound and they have ANY traffic, they try to vector you over Mexico. If you're returning from say San Antonio on a long XC, and are at 10,500 to 12,500 when you get the hand off from ABQ center to KELP expect an altitude restriction for your current altitude (will be to remain above 8000 at least). You'll be stuck up high until clearing their airspace leaving you about 10-12 miles to lose all that altitude.
 
Shawn said:
The repeat is often controller speak for start descending to help me out with approaching IFR traffic.
Click to expand...
^^^^ That

Often, you get the "descent at pilot discretion" nudge if you are close to a busy airspace. And it is a polite nudge.
The next thing you might hear in a few minutes is "descend and maintain X,000" so that they can ensure their other traffic separation.

Good question for sure. Do you have a friend pilot who can help you answer these? (nothing wrong with asking here)
When I was a student and even later as a greenhorn with a license, I'd either call up my ATP buddy with such questions or just take him out for beers and pick his brain. (I love talking to other pilots and picking their brains)
 
Dave S. said:
Controllers sometimes say things as prompts when more direct phraseology would be more appropriate. You are correct. The controller left it COMPLETELY up to you by giving you pilot's discretion. There's two possible reasons he repeated himself. The first is that he may have thought you didn't realize that you have his permission (blessing is a better word unless he stuck you at a hard altitude) to start down and he felt he needed to make sure you understood the descent at PD.

The second and more likely is that he really didn't mean what he said. What he may have wanted to get across is something to this effect..."N1AB, start the descent now", or something else. Who knows. Controllers use DPD so much that it becomes habit and isn't the most descriptive instruction for what they intend for you to do.

For example, I catch myself saying DPD sometimes as I drive an inbound into a gaggle of planes being sequenced with 10 or more airplanes within 15 miles of the field. I don't really mean to say that. What I MEAN to do is to manually fly that airplane, vector by vector and altitude by altitude and PLACE that airplane WHERE I NEED HIM TO BE. Something that DPD doesn't always accomplish. Many times the DPD is quickly followed by some other more specific instruction and probably should have been given in the first place to accomplish the controller's intent.

It's hard to say without knowing the big flick.

tex
Click to expand...

With you being a controller and a Display Name of "thetexan", this Texan wonders, where are you ATC'ing out of?
 
AU_James said:
So I'm a low time pilot and went on my first real cross country trip a couple weeks after getting my ticket with my fiancé. We're heading back home, I picked up flight following for the ~2 hr flight heading west at 6,500 in a club Cherokee 160. I get my last handoff and it's at night so I think I'll cancel flight following when I'm 100% comfortable with the lights near/around my home airport.

I'm traveling at about 100kts due to winds, traffic pattern altitude is 2,000' and I'm at 6,500' so I do some quick calculations and decide it'll take me about 15nm to descend and I want to arrive at TPA a few miles from the airport, so call it 20nm out to start my descent.

At about 35nm from the destination airport I hear, "Cherokee 123AB descend at your discretion." I reply, "Approach, 123AB, descend at discretion" and I continue flying at 6,500' because I still have a few mins before my planned descent. Roughly 3 minutes later (~5nm) I hear, "Cherokee 123AB descend at your discretion." I reply, "Approach, 123AB, will descend shortly at my discretion."

I wait anther few minutes, reduce power and descend nice and slowly/smoothly (this is only the second leg of my fiancé's first cross country), cancel flight following as I identify the airport, arrive at TPA a few miles from the airport where I've already turned the lights on, and make a decent night landing (her first) considering I just did 5-6 night landings the previous week at an airport nearby just in case we ended up coming back at night on this trip.

My question is why the controller repeated their communication when I definitely read it back and understood that I didn't need to tell them when I was descending? Sure, they could have missed my reply but we had no communication issues so far and there was some time between their transmissions. It made me feel like they were suggesting I begin my descent already but I was very assured in my plan. I also didn't want to get too low too early at night. I followed my plan and everything went well, but I'm just not sure of the intent behind the controllers repeated communication with me to descend.

Ultimately, no big deal at all, just looking for thoughts?

PS- this was also the first time the fiancé helped secure and tie down the plane, just to get her in the habit ;)
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Who knows why he said it a second time. Who knows why he even said it the first time. Some controllers like to talk more than others.
 
pkuhns said:
Excellent post because this is something I have dealt with many times, except the opposite: it's daytime and they never 'sign off'.

Example: I'm 10nm from my destination at 7500' and I'm still waiting for them to say something like "okay you're airport is 10 miles in front of you and there's no traffic so squawk 1200 have a nice day". That never comes and I'm way way over the top of my destination airport when I should have descended long ago.

This happens pretty much every time I get FF. I guess I'm supposed to just tell them "Approach/Center, 27161 has airport in site" but I'm worried they're too busy to hear such babble...
Click to expand...

I was bopping along VFR last night at 9500 msl, pattern was 1200. That's almost 8-1/2 thousand feet to lose, or 17 minutes at 500 fpm. As the GPS counted down through 19 minutes, I told Approach that I was beginning VFR descent. I was maybe 45 nm out? I think I had the city in sight, but certainly not the field.

Reporting "field in sight" is required for ATC to issue a visual approach to an IFR aircraft (even in VFR conditions).

Outside of B, C or D airspace, ATC doesn't tell VFR aircraft what to do, but they can certainly make suggestions. The way it's supposed to work is that you (the PIC) do what you want, and advise ATC. Sometimes I advise them that I am accepting their suggestion.

On last night's outbound leg, I climbed through a hole in the breaking up cloud layer and was told to change frequencies. The new voice asked a minute later, "for my own information, how high are you going to climb?" I had been at 3500, changed freqs at 6000 and climbed to 9500. Stayed there until I was ready to descend, pushed forward on the yoke and started trimming, then advised Approach what I was doing. That's how VFR works, and is what the PIC does.

P.S.--I usually hear the "airport is 12:00, XX miles, no reported traffic" when they want to drop me. Sometimes the distance out is further than the reported visibility . . . This is also more common when flying IFR in VMC conditions.
 
BigBadLou said:
Often, you get the "descent at pilot discretion" nudge if you are close to a busy airspace. And it is a polite nudge.
The next thing you might hear in a few minutes is "descend and maintain X,000" so that they can ensure their other traffic separation.
Click to expand...

Yup, got that a few weeks ago IFR at night in VFR conditions. Got "descend at pilot's discretion", was in no hurry, followed by N12345 descend and maintain 5000 a few minutes later (English for get your ass down now, please), right about that time I noticed the traffic off in the distance to the right.
 
Hank S said:
Outside of B, C or D airspace, ATC doesn't tell VFR aircraft what to do, but they can certainly make suggestions.
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Not sure where this notion that ATC can not / will not vector VFR aircraft comes from. I get specific headings assignments all the time from ATC both in SoCal and NorCal while on FF. Usually it involves while being vectored around approach paths of other airports but it certainly does happen quite frequently in controlled airspace outside B, C and D.

Out in no man's land it may be "suggest 10 degrees right" or so on, but specific vectors do indeed happen while VFR on FF.
 
Shawn said:
Not sure where this notion that ATC can not / will not vector VFR aircraft comes from. I get specific headings assignments all the time from ATC both in SoCal and NorCal while on FF. Usually it involves while being vectored around approach paths of other airports but it certainly does happen quite frequently in controlled airspace outside B, C and D.

Out in no man's land it may be "suggest 10 degrees right" or so on, but specific vectors do indeed happen while VFR on FF.
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It happens in Class C "outer areas" rather frequently. Those are not charted (they are Class E, but Class C services are provided) and cover a large hunk of both SoCal and NorCal airspace.

See AIM 3-2-4.b.
 
MAKG1 said:
It happens in Class C "outer areas" rather frequently. Those are not charted (they are Class E, but Class C services are provided) and cover a large hunk of both SoCal and NorCal airspace.

See AIM 3-2-4.b.
Click to expand...

The controller who was curious how high I was going to climb on Thursday was Atlanta Approach, just after he reminded me to stay out of the Bravo. I may have been 15 nm away when he asked how high I was going; my point of closest approach to the Bravo was about 2 nm. I've been asked to descend a little bit when flying through their arrival gate on the east side of the Bravo (landing 27, I'm flying south) at 8500, but they've never TOLD me what to do. ATC provides separation for IFR aircraft, I'm just something for them to dodge. Getting FF does us both a favor--it gets them looking out for me, and let's them know what I'm doing, improving safety for everyone.

But outside of B, C or D airspace, they can only advise, suggest and recommend. They can phrase it as an order, but I comply when and how I want to, unless they say "radar service terminated, squawk 1200." But I can also say the same thing to them . . . at any time.

It's all different when flying IFR, when everything from ATC is an instruction. When I don't file, there are no instructions outside of B, C and D; and airspace that is not charted does not exist--how am I supposed to know??? If you want pilots to comply, chart it so we know about it. Are you on double secret probation?

P.S.--AIM 3.2.4 (b):
b. Charts. Class C airspace is charted on
Sectional Charts, IFR En Route Low Altitude, and
Terminal Area Charts where appropriate.
How does this relate to ATC instructing VFR aircraft outside of B, C and D?
 
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Hank S said:
The controller who was curious how high I was going to climb on Thursday was Atlanta Approach, just after he reminded me to stay out of the Bravo. I may have been 15 nm away when he asked how high I was going; my point of closest approach to the Bravo was about 2 nm. I've been asked to descend a little bit when flying through their arrival gate on the east side of the Bravo (landing 27, I'm flying south) at 8500, but they've never TOLD me what to do. ATC provides separation for IFR aircraft, I'm just something for them to dodge. Getting FF does us both a favor--it gets them looking out for me, and let's them know what I'm doing, improving safety for everyone.

But outside of B, C or D airspace, they can only advise, suggest and recommend. They can phrase it as an order, but I comply when and how I want to, unless they say "radar service terminated, squawk 1200." But I can also say the same thing to them . . . at any time.

It's all different when flying IFR, when everything from ATC is an instruction. When I don't file, there are no instructions outside of B, C and D; and airspace that is not charted does not exist--how am I supposed to know??? If you want pilots to comply, chart it so we know about it. Are you on double secret probation?
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Well you could start by reading the AIM.

Lots of airspaces are not charted. CFAs, Class A, and ATCAAs, for instance.
 
MAKG1 said:
Well you could start by reading the AIM.

Lots of airspaces are not charted. CFAs, Class A, and ATCAAs, for instance.
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Can I fly VFR in Class A? No . . . It's also listed in the FARs as everything 18,000 msl and up. Never heard of the others . . . Are they controller-specific things?

And you do realize that, while it contains much good information, the AIM is not regulatory? Give me a quote where the FARs say that a VFR pilot in Class E/G airspace must obey ATC instructions. Look a long time, and read hard, because you won't find it. And no, anything quoted from 76whatever, the ATC Bible, doesn't count, either--it regulates what you are allowed to say in your comfortable chair on the ground, but has no bearing or relevance to me holding the yoke in the air.
 
Hank S said:
Can I fly VFR in Class A? No . . . It's also listed in the FARs as everything 18,000 msl and up. Never heard of the others . . . Are they controller-specific things?

And you do realize that, while it contains much good information, the AIM is not regulatory? Give me a quote where the FARs say that a VFR pilot in Class E/G airspace must obey ATC instructions. Look a long time, and read hard, because you won't find it. And no, anything quoted from 76whatever, the ATC Bible, doesn't count, either--it regulates what you are allowed to say in your comfortable chair on the ground, but has no bearing or relevance to me holding the yoke in the air.
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14 CFR 91.123(b) is rather unambiguous.

No, you can't ignore ATC instructions in Class E.

The AIM may not be rigorously regulatory, but good luck using that as a defense....
 
MAKG1 said:
14 CFR 91.123(b) is rather unambiguous.
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Read the whole sentence:

(b) Except in an emergency, no person may operate an aircraft contrary to an ATCinstruction in an area in which air traffic control is exercised.

Emphasis added. ATC doesn't exercise control over VFR aircraft in Class E and G.

And the AIM is not regulatory at all.
 
Unless I missed the bulletin that NORDO flight is now illegal, and so is flying along squawking 1200 and talking only on UNICOM, because I'm not talking to ATC and can't comply with whatever instructions they may want to issue me . . . Poor Cub pilots . . .
 
Hank S said:
Read the whole sentence:

(b) Except in an emergency, no person may operate an aircraft contrary to an ATCinstruction in an area in which air traffic control is exercised.

Emphasis added. ATC doesn't exercise control over VFR aircraft in Class E and G.

And the AIM is not regulatory at all.
Click to expand...
So, you'll bet your certificate on Class E not being controlled airspace?

This ought to be good.
 
^^^ See what I did there? I can do it to Atlanta Approach 3 nm outside the Bravo if I want to.

But I don't, because I like being safe. And I go a half hour around the Bravo every stinking time, when my direct course is over the top of ATL where there are no jets, and the controllers won't clear me into the T Routes created specifically to transit the Bravo.

Given another 50-60 hp, I'd give serious thought to climbing to 13,500 and going straight cause that's also outside the stinking nobody-bother-the-airlines-cause-they're-more-important Bravo.

Signing off for real this time . . .
 
Yep. Section A talks about operating on clearances. Section B as quoted says you can instruct me in areas where you exercise control. Section C is about deviating from a clearance in an emergency. Section D is also about emergencies. Section E is about clearances / instructions issued to other aircraft.

Which of these apply to VFR aircraft outside of controlled airspace not operating on a clearance? On my occasional trips to controlled fields, they clear me to depart, sometimes give me a heading, then when I leave their airspace, I'm on my own even if receiving optional FF services. I can climb, descend, turn left or right, or even change my destination without approval or notice.

Where do you read that you can give me instructions that I have to follow? Please provide the quote and an explanation, because I'm not seeing it. Key words: VFR flight, "areas where you have control." Quote FAR text, explain how it applies to me flying past ATL 5 nm outside the Bravo (you pick the direction, anything not aimed inside). You may assume that I am receiving Flight Following services, and that your workload permits you to provide them.

I think having "Controller" in your job title has gone to your head. Do you yell instructions to other drivers on your way to work in the morning?
 
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