IFR and ToD Question

RyanB

RyanB

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Looking for a little clarity on this.

So you’re at 12,000ft and flying IFR. The airport you’re landing at doesn’t have any STARs just a sleepy Class C.

You’re looking on your MFD and see your ToD point approaching. Do you advise ATC of this or will they already know and begin to step you down automatically? Of course with VFR flight, you simply tell ATC ‘Hey, I’m about to begin my VFR descent.’ How does this work for IFR?
 
ATC will descend you. When can depend on traffic and airspace. If you think they are keeping you at altitude too long, you can always ask for a descent.
 
Ryanb said:
Looking for a little clarity on this.

So you’re at 12,000ft and flying IFR. The airport you’re landing at doesn’t have any STARs just a sleepy Class C.

You’re looking on your MFD and see your ToD point approaching. Do you advise ATC of this or will they already know and begin to step you down automatically? Of course with VFR flight, you simply tell ATC ‘Hey, I’m about to begin my VFR descent.’ How does this work for IFR?
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It's very unlikely that ATC would know where the TOD is that your equipment displays. For one thing, it's not a fixed position. For example, with a G1000 the TOD moves if you speed up or slow down. Consequently, it's up to the pilot to do whatever is necessary to comply with ATC instructions and clearances (if possible).
 
Ryanb said:
Looking for a little clarity on this.

So you’re at 12,000ft and flying IFR. The airport you’re landing at doesn’t have any STARs just a sleepy Class C.

You’re looking on your MFD and see your ToD point approaching. Do you advise ATC of this or will they already know and begin to step you down automatically? Of course with VFR flight, you simply tell ATC ‘Hey, I’m about to begin my VFR descent.’ How does this work for IFR?
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Ask for what you need, most of the time you will get it, sometimes not. Sometimes you may need to descend faster than you would like. If you are not comfortable, tell them you can't descend that fast and need more time. Generally when I'm not given a descent I want, it's an airspace issue or a traffic issue. Typically they'll say unable, lower in 5 miles, or something to that affect. The thing that I learned in my training is not to be pushed into something unsafe by ATC. They have no idea what's going on in your cockpit, so you need to speak up. If you are not ready for an approach, ask for delay vectors. You may get a bigger delay than you bargained for, but at least you will be ready.
 
They’ll descend you on their own. We used to have a little cheat sheet formula on approach for descents. If it’s not working for you though, just ask. Especially during times you want a PD descent. Sooner you let them know, the easier for them to plan for it.

A lot of times they’re waiting for you to get out of the transferring controllers airspace (expect lower in X miles) and will descend you once you cross over their boundary. If the aircraft is really high though the transferring controller will most likely just key up the landline “Piedmont 3186 your control.” Same thing with point outs descending into another TRACON from above. Sometimes the TRACON beneath the aircraft being handed off from center will initiate a point out “Three five miles west Charleston 3506 code at one five thousand point out approved.” Now the receiving controller has permission to enter the airspace and the aircraft’s descent won’t be delayed. When it gets busy, expect to be held longer and not getting that type of treatment.
 
Roger that. Thanks for the input!
 
Sometimes I've had to ask. Sometimes, they've given it to me before I want. Sometimes they've given it to me when I wanted. And sometimes they've given it to me and I've asked if I could stay a little higher cuz of the tailwinds.
 
The only really scary time is when you've overflown your destination and they've not descended you. Oddly this happens since CLT gobbled up the airspace over my home field. ZTL knew where we were and would descend us. CLT routinely forgets where we are and I'm blasting down on the big airport before I can talk to them and let them know I don't want to go there.
 
Also keep in mind ATC can clear you for the approach with you utilizing the published approach features such as a holding pattern, DME arc, feeder route, or sector NOPT for your descent.
 
Most of the time ATC knows a good time to start your descent based on your aircraft, distance, and other restrictions. Just ask if you aren't getting what you want.

In the MU-2 my favorite (when I don't have pax to worry about) is to be kept up high as long as possible, and then do a flight idle descent. I was once solo going into JKA (near Pensacola). The controller gave me pilot's discretion from FL240 to 4,000, being used to the Blues playing around. So I waited until I was pretty close to the airport (I want to say around 20-30 nm), hit flight idle, and just pointed the nose down to Vne doing something around 3,500-4,000 FPM down.

I'm sure the controller yawned, given the pitiful performance of the MU-2 compared to an F/A-18.
 
In the Mooney, my descent gradient is very shallow - Around 6 miles per thousand feet. "Faraway Center, 7ST, request lower" is a frequent feature of my IFR flights. They almost always give me an immediate descent.
 
Ted DuPuis said:
Most of the time ATC knows a good time to start your descent based on your aircraft, distance, and other restrictions. Just ask if you aren't getting what you want.

In the MU-2 my favorite (when I don't have pax to worry about) is to be kept up high as long as possible, and then do a flight idle descent. I was once solo going into JKA (near Pensacola). The controller gave me pilot's discretion from FL240 to 4,000, being used to the Blues playing around. So I waited until I was pretty close to the airport (I want to say around 20-30 nm), hit flight idle, and just pointed the nose down to Vne doing something around 3,500-4,000 FPM down.

I'm sure the controller yawned, given the pitiful performance of the MU-2 compared to an F/A-18.
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The shop I worked at has half a dozen 331 powered aircraft and the overhaul shop recommended against idle descents. Something about it causing the turbine to rub. Maybe ask around see if there's any truth to it.
 
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flyingcheesehead said:
In the Mooney, my descent gradient is very shallow - Around 6 miles per thousand feet. "Faraway Center, 7ST, request lower" is a frequent feature of my IFR flights. They almost always give me an immediate descent.
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Same here in the Lancair. I like to keep the power wide open with a shallow descent to keep it below yellow arc (at least until reaching 6000ft or so, after which we're getting close to 75% power in any case, and even a shallow descent will result in yellow arc). That equates to around 500-600fpm for a cruise descent at around 210-220KTAS. ATC isn't expecting such a shallow gradient, hence, the need for "request lower."
 
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