vdp and tail stalls

[Jet_Dreamer]

hi all. I am looking for any detailed info on vdp's and tail stalls. any info would be great!
thanks.

 

[Dave Benjamin]

VDP can be calculated by dividing by the HAT by 300 which will give you distance in miles or if it's a timed approach you can divide the time in seconds by 10. A VDP is not "binding" however you need to make the landing using normal maneuvers and descent rate. If a VDP is not published I'd recommend calculating one and mentioning it during the approach brief.

Tail stalls are relatively uncommon. They can occur in certain icing conditions. According to the folks at NASA the tail stall will be preceded by a lightening of the control yoke and/or a tendency for the yoke to move forward. Recovery is opposite that of a wing stall. You will pull back on the yoke to reduce the AOA of the tail. If the tail stall was preceded by the extension of flaps put the flaps back where they were.

NASA has a video on tailplane icing. They also put out a CD. I think that Sporty's sells the video for 5 bucks as a public service. I'm not sure how to get the CD.

 

[bigsky]

On many non prec approaches you have a published vdp- which is basically where a normal 3 degree g.s. will intercept the lowest mda. On approaches without you can make your own vdp or pdp...visual or planned descent point.
As stated above divide the mda by 300--- works pretty well with most airplanes. If the mda is 930 and tdze is 100 the HAT is 830. We would plan on crossing the threshold at 50 so we really need to lose 780...divide by 300 and you get 2.6 miles.

The timing will change depending on airspeed. dividing by 10 works well for approach speeds of 120 kts. for example if hat is 650 and we cross threshold at 50 you divide 600 by 300 -and get 2 miles. divide 600 by 10 and 60 seconds.
The plane I currently fly has approach speed of approx 155-160 so I multiply by .8 for example 600 X .8 equals 48 seconds rather than the 60 seconds at slower speed... Can always use an e6b to tailor for your aircraft....

 

[Jet_Dreamer]

good information!! one other question. would a vdp ever be treated as a MAP.

 

[roundout]

Tail stalls are relatively uncommon. They can occur in certain icing conditions. According to the folks at NASA the tail stall will be preceded by a lightening of the control yoke and/or a tendency for the yoke to move forward. Recovery is opposite that of a wing stall. You will pull back on the yoke to reduce the AOA of the tail. If the tail stall was preceded by the extension of flaps put the flaps back where they were.

NASA has a video on tailplane icing. They also put out a CD. I think that Sporty's sells the video for 5 bucks as a public service. I'm not sure how to get the CD.

that video is wicked. i'm not sure how to get hold of it, but it's definately worth watching.

 

[spanky2]

VDP = MAP ??? Depends on several issues. What are you flying...a C-152 or a 767? How long is the rwy / is it wet / what are the winds? Extreme Example 1: on 7000' rwy in a big jet (767)...VDP is pretty much your MAP cause if I go beyond the VDP, use a 3 degree approach, I am landing pretty far down the rwy = unsafe. Example 2: I am in a C-152 and the rwy is 10000' long, I can have a MAP at the threshold and still safely land. Answer...it depends...but length of rwy is the key.

A new concept going around is CANPA. Constant angle non-precision approach. On a non-precision approach, begin a controlled descent from the FAF altitude ... about 700-800 fpm for a 737 at avg weight (not more than 1000 fpm) until MDA...at MDA, if not in a position to safley land...go around. No more "dive and drive" approach.

Fly safe.

 

[Dave Benjamin]

Don't treat the VDP just like a MAP. If you go missed you still need to initiate the miss from the MAP. You may elect to climb on your way to the MAP. Another option is if conditions allow you may wish to climb to the circling MDA and commence a circling maneuver if ATC, wind, and performance limitations permit. You really need to think things out before you get to the VDP and have a plan. Let ATC know you might need the circle. Have performance figured out before you even start the approach. You don't want your FO/PNF to be pulling out the perf data and calculating the tailwind hit at 500 AGL.

 

[Jet_Dreamer]

all good info, thanks a lot!!

dave- is the tail stall stuff you posted text book skywest?

 

[Dave Benjamin]

dave- is the tail stall stuff you posted text book skywest?

No, more like textbook NASA. I'm sure many airlines use the NASA video for training.

 

[TopGun-MAV]

wot is a vdp?

i can help you out with the tail stalls. pm me if you need help

GOO THE MAV!!

 

[GVFlyer]

Fox Two is the Aim 9 Sidewinder

.

 

[IP076]

Re: Fox Two is the Aim 9 Sidewinder

Maybe they teach Fox Two as being something different in that "High Paying" Beech 1900 class.


Not the company, but the pilot.

Maybe you should have paid the Government to put you through OCS......

 

[boxjockey]

A new concept going around is CANPA. Constant angle non-precision approach. On a non-precision approach, begin a controlled descent from the FAF altitude ... about 700-800 fpm for a 737 at avg weight (not more than 1000 fpm) until MDA...at MDA, if not in a position to safley land...go around. No more "dive and drive" approach.

I used to teach this method when I taught for KLM airlines. They were very big on these calculations, especially for the numerous NDB approaches still used in Europe and other areas. Requires a little advanced planning, but makes for a very stabilized approach.

box