VNAV: descent out of 10,000 to a straight-in visual.

C150J

C150J

Well-Known Member
Hi guys -


Trying to get more comfortable with VNAV outside of the simple stuff (crossing restrictions, pre-programmed SiDS/STARS, etc.). Say you frequently fly into an airport where you're set up for a straight-in visual and are generally cleared to do so at about 10,000 feet. If you were to follow the path, you would obviously never have a level-off to slow and configure. Would most of you designate a level-off point/speed target (e.g., a pilot-designated eight mile fix at a safe "below-path" altitude), then pick up another path at a 5-mile fix?


Maybe I'm over-thinking this, but I am trying to get more comfortable with the automation. I have several ideas on how to accomplish this (like the one above), but am curious as to how most would go about doing it (aside from clicking it all off and having fun:)).


Thanks!
 
I guess it would all depends on the type of approach you're doing, your ops specs (LNAV only? LNAV/VNAV? RNP?), and the congestion at the airport you're flying into.

We have LNAV/VNAV and RNP on our Q400's, and it works like a charm. The Universal UNS-1 that we have will back calculate the altitudes for you if you're starting an approach from an IAF all the way down to the MAP...so essentially you have a seamless transition across all fixes and it's a constant descent.
 
C150J said:
Hi guys -


Trying to get more comfortable with VNAV outside of the simple stuff (crossing restrictions, pre-programmed SiDS/STARS, etc.). Say you frequently fly into an airport where you're set up for a straight-in visual and are generally cleared to do so at about 10,000 feet. If you were to follow the path, you would obviously never have a level-off to slow and configure. Would most of you designate a level-off point/speed target (e.g., a pilot-designated eight mile fix at a safe "below-path" altitude), then pick up another path at a 5-mile fix?


Maybe I'm over-thinking this, but I am trying to get more comfortable with the automation. I have several ideas on how to accomplish this (like the one above), but am curious as to how most would go about doing it (aside from clicking it all off and having fun:)).


Thanks!
Click to expand...

What type of fms/gps? Normally I will load a gps approach and build altitudes off it. If you have a universal, there are a lot of cool things you can do

Sent from my DROIDX using Tapatalk
 
SurferLucas said:
I guess it would all depends on the type of approach you're doing, your ops specs (LNAV only? LNAV/VNAV? RNP?), and the congestion at the airport you're flying into.

We have LNAV/VNAV and RNP on our Q400's, and it works like a charm. The Universal UNS-1 that we have will back calculate the altitudes for you if you're starting an approach from an IAF all the way down to the MAP...so essentially you have a seamless transition across all fixes and it's a constant descent.
Click to expand...

it will do it from tod on a sid with an approach transition if you want it to...that damn alt sel ruins the fun though. Very capable vnav machine otherwise

Sent from my DROIDX using Tapatalk
 
I don't normally do this, but here's something you could build.

Put in a fix 30 miles from the field. Set the altitude to Field Elevation + 10000

Put a fix in 10 miles from the field. Set the Altitude to Field Eleveation + 3000

We accomplish this in the FMS3000 by putting a "KTOL/-30" and "KTOL/-10" (in that order) on the legs page before KTOL (assuming you are direct to the field).

Use the VNAV to hit the waypoints at the right altitudes/airspeeds on the way down.

Then again, I fly a turboprop so we can go down and slow down at the same time to configure. If you fly a jet, it might be a good bet to take it to an altitude below the 3* path to the runway to give you time to configure.
 
SurferLucas said:
I guess it would all depends on the type of approach you're doing, your ops specs (LNAV only? LNAV/VNAV? RNP?), and the congestion at the airport you're flying into.
Click to expand...

Thanks for the replies, guys!

We are approved for everything - I am comfortable shooting "real" approaches/arrivals with the thing (Honeywell NZ-2000), but like Tuck's idea concerning adding altitudes off a pre-existing approach.

I'm mainly looking for a way to build a highly-efficient visual approach that gives me a level-off to configure before the last 1500' (3 miles). I can do it several ways, but wanted to see if you guys have any tricks.

Thanks again!
J.
 
C150J said:
Thanks for the replies, guys!

We are approved for everything - I am comfortable shooting "real" approaches/arrivals with the thing (Honeywell NZ-2000), but like Tuck's idea concerning adding altitudes off a pre-existing approach.

I'm mainly looking for a way to build a highly-efficient visual approach that gives me a level-off to configure before the last 1500' (3 miles). I can do it several ways, but wanted to see if you guys have any tricks.

Thanks again!
J.
Click to expand...

You can build a vfr in that fms, I believe under airport or pilot data...i forget-been a while- then add initial fixes before the faf.

The uns one flow is simple, data-pilot data-approaches-aproach def- select airport, app type(vfr) add leg to eao heading and distance, -next, input the faf to eoa glide path angle. The goback to page 1 add initial fixes with altitude constraints if you like. Then just load it like an rnav/vnav

Sent from my DROIDX using Tapatalk
 
TUCKnTRUCK said:
it will do it from tod on a sid with an approach transition if you want it to...that damn alt sel ruins the fun though. Very capable vnav machine otherwise
Click to expand...

Yep, that's the stupidest thing on the Q400, among many stupid things.

At QX, every approach we fly has some sort of vertical guidance. Even VOR/LOC/LOC-BCS with no GPS overlays. The UNS-1 is capable of RNP of 0.1, which is what we're currently applying for with the FAA.
 
I'm typically off the VNAV by about 10,000', but that's just personal technique. It generally does a decent job until the 10,000' deceleration, but beyond that I feel that there are usually too many variables to program in an accurate VNAV profile. The most I'll do below 10,000' is input the FAF altitude, but I'll generally do the descents in FLCH and adjust speed manually, using the Chinese glideslope as a general reference rather than a specific targeted profile.

Again, all personal technique.
 
dasleben said:
I'm typically off the VNAV by about 10,000', but that's just personal technique. It generally does a decent job until the 10,000' deceleration, but beyond that I feel that there are usually too many variables to program in an accurate VNAV profile. The most I'll do below 10,000' is input the FAF altitude, but I'll generally do the descents in FLCH and adjust speed manually, using the Chinese glideslope as a general reference rather than a specific targeted profile.

Again, all personal technique.
Click to expand...

^ Couldn't agree more
 
Thanks for all of the information!

Lots of great tips/tricks. Makes me more comfortable reverting to vertical speed, capturing an altitude, configuring, then starting down on an approach if I don't want to build anything. Just not used to see a path being calculated after every move I make - made me feel like I almost had to use it.
 
I'm with those who dislike VNAV (w/autopilot) below 10k. Vertical speed works just fine, and then you KNOW what it's going to do and can just react with the power levers.
 
N519AT said:
I don't normally do this, but here's something you could build.

Put in a fix 30 miles from the field. Set the altitude to Field Elevation + 10000

Put a fix in 10 miles from the field. Set the Altitude to Field Eleveation + 3000

We accomplish this in the FMS3000 by putting a "KTOL/-30" and "KTOL/-10" (in that order) on the legs page before KTOL (assuming you are direct to the field).

Use the VNAV to hit the waypoints at the right altitudes/airspeeds on the way down.

Then again, I fly a turboprop so we can go down and slow down at the same time to configure. If you fly a jet, it might be a good bet to take it to an altitude below the 3* path to the runway to give you time to configure.
Click to expand...


If VNAV is used below 10k then this sounds like a fairly logical way to do it.
 
surreal1221 said:
Sometimes just flying the plane using pitch / power is easier than relying on the automation...

:)
Click to expand...

Completely agree with you! Just trying to better understand VNAV/Autospeed/Autothrottle capabilities - definitely a different way of thinking than my old plane!
 
Boris Badenov said:
I'm with those who dislike VNAV (w/autopilot) below 10k. Vertical speed works just fine, and then you KNOW what it's going to do and can just react with the power levers.
Click to expand...


There you go with that "flying" the airplane thing again. This is the new age of aviation, you are supposed to program the "box" and have it fly you, not the other way around. Get with the times, you neanderthal pilot.
 
CzechAirman said:
There you go with that "flying" the airplane thing again. This is the new age of aviation, you are supposed to program the "box" and have it fly you, not the other way around. Get with the times, you neanderthal pilot.
Click to expand...

Unfortunately, it seems like a lot of airplanes are making it harder to "click it off" than before, not to mention ops manuals.
 
CzechAirman said:
There you go with that "flying" the airplane thing again. This is the new age of aviation, you are supposed to program the "box" and have it fly you, not the other way around. Get with the times, you neanderthal pilot.
Click to expand...

It's amazing the number of people I see who are afraid to fly the airplane. VMC day, configured and stable on a 10 mile final, autopilot to 200'. Defeats the whole purpose of why I got into this business.
 
dasleben said:
It's amazing the number of people I see who are afraid to fly the airplane. VMC day, configured and stable on a 10 mile final, autopilot to 200'. Defeats the whole purpose of why I got into this business.
Click to expand...


I've been in the airlines since 1986 and I've grown very lazy in my old age, so I often let the a/p fly the jet most of the way up and down. The thing is that I can hand fly the jet competently when I want/need to, years of 135 single pilot night freight will make you confident/competent at hand flying the plane. Unfortunately, I've seen and flown with way too many pilots that can't competently/confidently fly the jet manually. It seems like today's new generation of pilots (especially at the regional level) are not confident flying the jet manually and some are borderline competent doing it.

Some of the scariest words a new age pilot will hear from ATC is "cleared for the visual".
 
You must log in or register to reply here.
Back
Top