ozzy

TNKS- Big D. Appreciate all the help I may get.

UNDGUY

Glad to hear I get to be the geunie(spelling?) pig for the sim on Tuesday. I'll let you guys/gals know how it goes.

Figuring a VDP: Three times the altitude to lose. IE. MDA is 1800 MSL, touchdown zone elevation is 1400 MSL. Difference is 400 ft times three which equals 1200 or 1.2 nautical miles. Is that correct?

Calculating a descent is what gets me. Different pilots use different methods. What is the accepted method in the airlines. Do they use the 3/6 rule. (3 times the altitude to lose to get distance out, and 6 times your groundspeed to get descent rate)

Or my boss said to always use time. If your going to descend at 1000 fpm and you have to lose 10000 feet you start your descent 10 minutes out based on your groundspeed.

What if your twenty miles from a fix and the controller tells you to cross the fix at a certain altitude. IE. At 15000, controller tells you to cross the fix at 4000 and the fix is twenty miles away.

Thanks in advance

Lanesuzza

your Altitude 15,000'
Airport is 1,000
difference 14,000
15 - 1 = 14
14 x 3 = 42 miles
42 + 4 (10%) = 46 miles out to start descending.

The 10% is for cushion and works great!


Rate of descent.
1/2 of groundspeed add a zero

ground speed = 180
then 1/2 of 180 = 90
90 add a "0" = 900 fpm descent rate.


This works well for me.

UNDGUY

Ok, so there is yet another way to calculate a descent, which brings me back to my original question. Is there a particular way that the airlines teach? If I am asked to do this for the interview test how should i calculate it?

BigDaddy

The test is multiple guess, so I wouldn't worry too much about it.

POPA

"Unable."
For scenarios that are possible, though: just figure out how far it's going to take you to descend and begin your descent that far from the fix.

ozzy

Quick question about the Dash-- what approach category is it? I think its B (91-120). also what is the approx. ref speed that is used??

Lanesuzza

The method I use was taught to me by a training captain at a certain unnamed "airline".

Laxrox43

Ozzy,

The Vref depends on weight and landing configuration...but 9 out of 10 times...yes...Cat B.

I haven't flown the sim with the -300 weights and speed cards...so any guys on the line...could you answer the same question for the 'long-body'?

Booker

If I remember correctly, it wasn't much faster--still a Cat B airplane. Maybe another ten knots? Hopefully someone who is current can expound.