Vertical path non-precision approach safety?

ppragman said:
I hate to be the bad guy here, but I actually have to agree with the airline jockeys. The truth of it is, with dive and drive you have to adjust pitch and power at least once (at Bottom of Descent) and on some wacky approaches you may have to adjust pitch and power multiple times. I prefer that the only power adjustment I make is the power reduction in the flare or pushing the power up to go missed. I wish we could have the OpSpec and technology to do that in the Navajos, PC-12, and Caravan we fly.
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There's nothing wrong with agreeing with an airline jockey. So much of this is a function of mass as well. You can get away with things in a 'ho, King Air, or Commander (and even in the Brasilia) that you can't get away with (repeatedly, smoothly etc.) in a 757 due to sheer inertia. Even in the ERJ, leveling off at MDA was a large thrust and pitch attitude change.
 
Autothrust Blue said:
There's nothing wrong with agreeing with an airline jockey. So much of this is a function of mass as well. You can get away with things in a 'ho, King Air, or Commander (and even in the Brasilia) that you can't get away with (repeatedly, smoothly etc.) in a 757 due to sheer inertia. Even in the ERJ, leveling off at MDA was a large thrust and pitch attitude change.
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Putting out flaps 45 is a HUGE power change in the ERJ. Because the speed is so low to get flaps 45 out, you take out a ton of power to get slow enough to get the flaps out, and then have to bring the power back up to 65-70% N1 to stay on speed and on GS on an ILS. But not too soon, or you'll overspeed the flaps! Frankly I can't even remember how much power we had in while we were tooling around with everything thrown out in order to maintain altitude. 90% N1? It had to have been high as heck. Doing that while trying to look outside the plane to find a runway while you're in and out of the bases, while you're trying to make sure you either manually capture the MDA, or make sure the autopilot does it, made for a sporting approach.

I'm glad we're not doing that crap anymore.
 
jtrain609 said:
Putting out flaps 45 is a HUGE power change in the ERJ. Because the speed is so low to get flaps 45 out, you take out a ton of power to get slow enough to get the flaps out, and then have to bring the power back up to 65-70% N1 to stay on speed and on GS on an ILS. But not too soon, or you'll overspeed the flaps! Frankly I can't even remember how much power we had in while we were tooling around with everything thrown out in order to maintain altitude. 90% N1? It had to have been high as heck. Doing that while trying to look outside the plane to find a runway while you're in and out of the bases, while you're trying to make sure you either manually capture the MDA, or make sure the autopilot does it, made for a sporting approach.

I'm glad we're not doing that crap anymore.
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I'm aware, Holmes. I resolved to no longer do it after I experienced it 'for real'.

Don't some of the east airplanes have the 165-knot kit?
 
Autothrust Blue said:
There's nothing wrong with agreeing with an airline jockey. So much of this is a function of mass as well. You can get away with things in a 'ho, King Air, or Commander (and even in the Brasilia) that you can't get away with (repeatedly, smoothly etc.) in a 757 due to sheer inertia. Even in the ERJ, leveling off at MDA was a large thrust and pitch attitude change.
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I would love to put some of these posters in the actual airplane and have them actually do a dive and drive approach. Big thrust changes, pitching moments, lots of trimming. Then go back and do the same approach with VNAV.

"Oh. That's what you were talking about."
"Yeah."

:)
 
UAL747400 said:
What is the spool-up time with a bigger turbine engine? I was under the impression that as long as you're not at flight idle, you'd have plenty of power pretty quickly. I mean, even the PT-6 takes 5 seconds to get anything from flight idle. I don't think @z987k is unfamiliar with slow engine response...
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Depends on the engine, but turbofans don't spool very fast.

Slow and low can be a deadly combination.
 
Another thing to consider as well, is that CDA arrivals, different than CANPA, will probably end up in the United States so that's a whole 'nother thing to think about.

Then once we get ADS rolling at a modern level, your airplane becomes one big snitch bot.
 
Tall Doug, don't we hold off on final flaps until landing is assured on a NPA, then add once determined to leave MDA? (It's fading away now...)
 
dasleben said:
I would love to put some of these posters in the actual airplane and have them actually do a dive and drive approach. Big thrust changes, pitching moments, lots of trimming. Then go back and do the same approach with VNAV.

"Oh. That's what you were talking about."
"Yeah."

:)
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When the ILS was out of service in TUP last year during their runway construction, we were routinely flying the NDB 36. The NDB also serves as the FAF for the ILS, so when the ILS finally came back into service, it was nice to see what we were flying as "dive and drive" vs the glideslope on the ILS. After seeing both, I would gladly take a VNAV enabled non-precision approach any day of the week and twice on Sundays :)

Another thing to think about when comparing "dive and drive" vs VNAV. Think about OEI operations. I know on the Saab, it takes 90+% Tq just to hold MDA at our adjusted vRef. With the yaw damp more or less handling the rudder inputs and our no autopilot below MDA policy, leaving the MDA to land from a "dive and drive" approach leaves you with an airplane that is whacked out trim wise while you are trying to transition from the panel to visual. I'd much rather have a constant decent profile where I can set the power and the trim and not touch anything until I reduce the power and flare.
 
and if you do it right you can hit the corners of the step-downs with a stabilized approach and reach MDA just prior to VDP so you can look, then if you don't see it, you can add the power to hold MDA for a second or 5 and take a better look, then finish adding the power for the missed anyway...
 
Derg said:
Another thing to consider as well, is that CDA arrivals, different than CANPA, will probably end up in the United States so that's a whole 'nother thing to think about.

Then once we get ADS rolling at a modern level, your airplane becomes one big snitch bot.
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You mean from the flight levels? I think they call them Optimized Descent Profiles, and they already have them in at a handful of airports. Denver is notable for us as we don't have real VNAV, so making them work is a little...interesting.
 
jtrain609 said:
You mean from the flight levels? I think they call them Optimized Descent Profiles, and they already have them in at a handful of airports. Denver is notable for us as we don't have real VNAV, so making them work is a little...interesting.
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Well, it's more like what they do in London where they'll say "20 air miles to the airport, descend and maintain XXX cleared for the approach" and you're supposed to manage your descent as to not level off or descend slower than 200 fpm or the approach monitors violate the crew.

It's largely a pain in the ass and I wish they'd get off their duff and just create an approach transition.

They always mail a threatening letter to your chief pilot about your descent management if you screw it up, including crew names and some of the metrics of the violation.

The only thing LHR has going for it is the "green light taxiway" system. Crap, I gotta go next month...
 
Derg said:
Well, it's more like what they do in London where they'll say "20 air miles to the airport, descend and maintain XXX cleared for the approach" and you're supposed to manage your descent as to not level off or descend slower than 200 fpm or the approach monitors violate the crew.

It's largely a pain in the ass and I wish they'd get off their duff and just create an approach transition.

They always mail a threatening letter to your chief pilot about your descent management if you screw it up, including crew names and some of the metrics of the violation.

The only thing LHR has going for it is the "green light taxiway" system. Crap, I gotta go next month...
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Uhm, they're obviously unclear about what "descend and maintain (altitude or flight level)" means. I'm sure there's at least one CFII around that could take them to school on that...
 
Autothrust Blue said:
Uhm, they're obviously unclear about what "descend and maintain (altitude or flight level)" means. I'm sure there's at least one CFII around that could take them to school on that...
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They don't use "maintain" in their phraseology.

It's either "XXX, descend to flight level _____" or "XXX, descend to altitude _____."
 
dasleben said:
They don't use "maintain" in their phraseology.

It's either "XXX, descend to flight level _____" or "XXX, descend to altitude _____."
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Turn left ten degrees maintain level three hundred report radar heading to Shannon on one three four decimal two five zero seven eight four two FIFE.
 
Derg said:
I can remember exactly four numbers.
The radio frequencies internationally are two digits too long to remember.
135.2 - Easy peasy.
135.625 - Crap, say again?
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It's not just remember the numbers either. We have 4 ex Qantas planes here that have the 3 decimal radios. It takes so long to spin the damn frequency in that half the time I've forgotten what it was by the time I get close.
 
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