Welcome to Flightinfo.com

  • Register now and join the discussion
  • Friendliest aviation Ccmmunity on the web
  • Modern site for PC's, Phones, Tablets - no 3rd party apps required
  • Ask questions, help others, promote aviation
  • Share the passion for aviation
  • Invite everyone to Flightinfo.com and let's have fun

Mental Math

Welcome to Flightinfo.com

  • Register now and join the discussion
  • Modern secure site, no 3rd party apps required
  • Invite your friends
  • Share the passion of aviation
  • Friendliest aviation community on the web
Hi!

B+: I am normally about 150 knts in 2nd segment climb-how does that work?

Also, in the climb from 1000' to 3000' agl we are normally at 200, and then after 3000' agl we're 250.

How do you figure the angle for 150/200 and 250. I'm good at math, but I only had 1 math class in college!

Thanx 4 the help!

cliff
BNA
 
Cliff, you only need to find the angle required for the departure. No matter what speed you climb out single engine, just look at the 100-knot ROC on the chart. That will give you the angle of climb required for the departure. Use that angle against your single engine climb charts to see if you can do the departure. Two-engine climbs are almost always well above the requirements for the departure, so that's where your climb profiles come in. Otherwise, you're climbing at V2 until a safe altitude.
 
Last edited:
Hi!

Thanx 4 that explaination.

cliff
BNA
 
Hi!

B+: I am normally about 150 knts in 2nd segment climb-how does that work?

Also, in the climb from 1000' to 3000' agl we are normally at 200, and then after 3000' agl we're 250.

How do you figure the angle for 150/200 and 250. I'm good at math, but I only had 1 math class in college!

Thanx 4 the help!

cliff
BNA
The reason the 100 knot ROC converts easily is because of the following math.
At 100 knots you will cover 10000 feet per minute.
Gradient is rise over run so if the required ROC at 100 kts is 680 fpm then 680/10000=.068 or 6.8%.
You would get the same gradient using any other of the speeds but the math would not be as easy since the distance traveled in a minute will not be the nice round number like it is at 100 kts.
 
A quick rule for the Vnav planning:

1000s of feet to lose X 3 (as stated previously) AT

Groundspeed X 6 (for descent rate).

500 knots groundspeed covers 8.3 nm/min. If you need to lose 30,000 feet for a crossing restriction, you need to start 90 miles prior to the restriction (30 X 3). It will take you just under 11 minutes to cover the 90 miles in the descent (10.8 to be more precise). In order to lose the 30,000 feet in the 10.8 minutes, you would need a descent rate of 2777 ft/min.

Using the gs x 6 method, at 500 kts groundspeed, you get 3000 ft/min for the descent. I like this method because it typically gives a little buffer prior to the restriction. I also reevaluate the numbers every couple thousand feet in the descent.

I'm a geek . . . I know.
 

Latest resources

Back
Top