Descent Rate - YYZ terminal.

[unregistered]

Hi,

When you give a descent clearance to a pressurized aircraft in the terminal area, what do you expect as a minimum descent rate - and what do you prefer (if greater).

Or don't you care?

Thanks in advance.

[Flying Low]

Not sure what other turboprops usually do but our SOP's on the MU-2 are a 2000 fpm descent on the barber pole (250kts). I don't think YYZ expects this as they give us a descent our discretion and then tell us to start our descent a little later when we are still up high.

We do tailor our descents for conditions; for example, if we are getting an amazing push up high we will stay up longer and descend at 3000 fpm on the barber pole. Conversely, if we are getting strong headwinds we might plan our descent for 1000 fpm on the barber pole and start earlier to duck the headwinds.

It would be interesting to hear what ATC considers "standard descent" for us.

[YYZ Tower]

Not really my area but if you're inbound to YYZ you'll probably get descent from 8000 at about 25 miles out on a straight-in. When coming from elsewhere you can expect to leave 8000 when abeam the airport on the downwind. Depending on traffic you'll have a minimum of about 22-25 miles left. The actual distance would normally be given by the controller. Your rate of descent in the downwind might need to be quite high (2000-2500fpm) so as not to arrive on final too high if the pattern is short.

I think there is a minimum required rate of 500fpm but don't ask me to quote a reference!

[unregistered]

Thanks for the replies. I'm not sure why I specified YYZ terminal exactly, other than the fact that I do most of my flying there.

I have a personal rule of thumb which is 500-1000fpm in an unpressurized aircraft and 1500fpm if pressurized (notwithstanding some sort of "level by" request).

My premise had always basically been comfort, I can descend the pressurized twin at 1500fpm and, at the same time, descend the cabin at 500fpm. Don't have that luxury in the unpressurized craft.

Anyway, lately, I had been noticing that all of my co-pilots had been doing something different and our SOP's only reference rate of descent with respect to an approach, so it peaked my own curiosity about what is actually expected on your end, or what you prefer to see.

Your replies are actually very interesting.

Thanks again.

[The Velvet Fog]

1500- 2000 fpm should be a good average. If it's a long final, less is fine, but bear in mind that we have to turn on to the localizers with 1000 feet vertically unless we're doing visuals(which is why we are always asking if you see the field. You'll still likely get a vector to final to provide space to allow for a departure between two landers but seeing the field allows us to discontinue vertical and keep you on the glideslope). The south side runways are nomallty the "low" side so you need to be at 4000 feet before base to turn in beside traffic at 5000 on the other side

You will mostly get warned ahead of time if you're going to be "slammed" into an 8 mile final. It is rather frustrating to tell a crew to plan for an 8 mile final when 15 north of the field and then have them cross HERKI at 7500 feet at 500 fpm.

Hope that helps a bit.

Mel

[smooth1]

Quite often you can base your rate of descent on the altitude you should be at the next waypoint. Very often on a STAR, waypoints have altitudes associated with them. In YUL, for example, landing 24's, we need you at BIVRO (abeam the field on downwind) at 6000ft. So if you're leaving, say 14,000 20nm from BIVRO, the distance will determine your rate of descent. The wind needs to be considered. If no reference altitudes are published, as an approach controller, I would want you to be turning base at just below 4000ASL, assuming a 10nm final.

Hope that helps.

[justplanecrazy]

I think its not so much what rate the controller expects vs. type but rather what rate vs. altitude and distance remaining. If you're talking about descent to an airport, they'll base they're altitude step downs in order to allow your type of aircraft to get down in time. They're probably not expecting the "barber pole" descent as soon as they say altitude your discretion, but if you're given descent clearance and its obvious you are hanging yourself up, then they'll expect a dive for the threashold approaching the field. Basically, like smooth1 said, set the rate at what you need to get down to the right altitude for the situation. If you're battling headwinds then make it steeper and if it isn't working for ATC, they'll stop you.