Interview questions...climb gradients

[gordon24]

Looks like most fracs ask a climb gradient question or two at the interview. Anyone care to expand on what they might ask? I'm part 121, so, I'm little rusty at this stuff. My buddy told me he was asked to covert a climb gradient % to feet per minute. Anyone know a quick way to solve that?

Thanks,

 

[Diesel]

a quick tip is take the chart that shows the feet per minute that you need on the climb gradiant in the chart. Look for the 100 block. Move the decimil over one so it would look like this

400 597<----- move the decimil over one 5.97 is mind climb grad
80 100

sorry i can't make it more clear there are guys who can better explain it.

 

[flyboycpa]

diesel is correct,

if you look on a departure procedure plate, take a look at the box that shows the required climb (in feet per minute) given a certain climb requirement in feet per nm, as follows for Eagle CO (KEGE):

Grnd Spd-Kts 75 100 150 200 250 300

480' per NM 600 800 1200 1600 2000 2400
750' per NM 938 1250 1875 2500 3125 3750

Depending on which DP you are assigned (or filed), read the required fpnm as shown on the procedure (either 480 or 750 fpnm) and look at the "100 knot" column to determine that at 480 fpnm requires an 8.00% climb gradient; likewise, the procedure that mandates the 750 fpnm requires a 12.50% climb gradient.

Hope this helps,
fb

 

[HSDriver]

Converting % climb gradient to FPM...

If you just have to do it off the top of your head in an interview that is trivia but here goes.

First of all since the % gradient is based on a mile ask yourself what the percentage would be in feet. Ex. 10% would be 600 feet right? So now you have how many feet you have to climb in a NM. 600 Feet per NM.

Second question...How fast am I going? Maybe a typical V2 would be 120 knots...That sounds good and makes the math easy for me anyway. So I am traveling at two miles per minute and I have to be climbing at 600 feet per NM. SO...I need to be climbing at 1200 Feet per minute.

Hope your not too confused now.

 

[TonyC]

Climb Gradient (%) to Climb Rate (fpm)

Looks like most fracs ask a climb gradient question or two at the interview. Anyone care to expand on what they might ask? I'm part 121, so, I'm little rusty at this stuff. My buddy told me he was asked to covert a climb gradient % to feet per minute. Anyone know a quick way to solve that?

Thanks,

>>>>>>>>> FORMULA:

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Climb Rate (fpm) = Climb Gradient (%) X 60.8 ((ft/NM)/%) X Groundspeed (knots or NM/hr) X 1/60 (hr/min)

<><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>

Climb Rate (fpm) = 1.013 (Climb Gradient X Groundspeed)

Example:

Climb Gradient = 3%

Groundspeed = 120 knots

Climb Rate = 1.013 ( 3 X 120 ) = 364.68 FT per minute



>>>>>>>>> "RULE OF THUMB":

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Climb Rate (fpm) = Climb Gradient (%) X Airspeed (knots)

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(This "Rule of Thumb" ASSUMES 60.8 = 60 and groundspeed = airspeed.)

Example:

Climb Gradient = 4.5%

Airspeed = 150 knots

Climb Rate = 4.5 X 150 = 675 ft per minute


If the winds are negligible, use airpseed instead of groundspeed, and use 1.0 instead of 1.013333. If you are climbing with a substantial tailwind, the approximation becomes less valid. A higher climb rate in feet per minute will be rquired when the tailwind is pushing you closer to the obstacle(s).

This is off the top of my head - - please correct me if I'm wrong. If it's correct, I suppose we could offer it to the "Rules of Thumb" section of this board for future reference.

[Edited for formatting]

 

[vossdr1]

Climb Gradient

Ground Speed/60 X required gradient = VSI

 

[vossdr1]

The VSI typically displays feet per minute. The ground speed is typically nautical miles per hour. There are 60 minutes in an hour. By dividing ground speed by 60 you get nautical miles per minute. Required gradient for this equation should be expressed in feet per nautical mile. By multiplying feet per nautical mile (grade or rise over run) by the number of nautical miles per minute, you get a number that should be indicated on the VSI to meet that gradient (rise over run).

Hope this helps.

 

[flyboycpa]

another really really simple answer...

just look at the Jepp chart that has already done the calculation for you!! Keep a copy of it in your fight bag! Sorry, I don't have it handy at the moment, otherwise I'd give you the page #.

fb

 

[TonyC]

Required gradient for this equation should be expressed in feet per nautical mile.

But in this problem, it is not. In this case, the Climb Gradient is expressed in per cent, as in , a 3% climb gradient. Such a requirement in such a form is not that uncommon, but the % is what makes the solution less obvious.

If one understands that 1% climb gradient is equivalent to 60.8 feet per nautical mile, then the solution follows.

The answer you gave looks correct, but it answers a different question.

 

[vossdr1]

Tony,
Yes, I suppose it helps to read the question.