Calculating climb gradient?
 

I had a buddy who was recently asked on an interview to calculate a climb VSI for a climb gradient for a DP off of a jepp chart. Anyone have any idea how to do this? Any rule of thumb how to do this without the table?

I believe jepp includes a climb gradient table. I know the FAA charts have a table in the back.

Thanks.

calculating climb gradient
 

Ground Speed/60 will give you your miles/min..multiply that by the ft per NM in the DP and there you have it!

There you go. </thread>

You can also use the E6B computer. Set the Rate (60) under your ground speed. The outer side will read your feet per minute climb, and the inner scale will read your feet per nautical miles. Hope that helps.

If I may ask (and if you know) what was he interviewing for?

When gradiënt is given in percentage as usually is in climbs, simple groundspeed times percentage!

Climb gradient is 3.3, gs approx 160, required vs is roughly 520

I like using the units and
120Nautical Miles (nm) per 1 hour = 120nm/ 1hr
or 120nm / 60minutes(min) which equals 2nm / 1min
Required climb gradient for the Pitkin four out of KASE = 500ft/1nm
ft/min required = 2nm/1min * 500ft/nm
=
2nm * 500ft
------------
1min * 1nm

equals 1000ft/1min
note the nm cancel out and you're left with ft/min as your units.

Of course you're flying a part 25 aircraft and ahh screw it, if we lose one we'll just go visual down to Rifle. . .

2nd segment enforcement?
 

Has anyone, non part 121, DIRECTLY been involved with an enforcement action (investigation) regarding OEI climb requirement calculations?

Anyone?

Can't help you there but this video may help you clear up some misinformation:

TAPP Working Group Video (Part 1 of 4): Planning For Takeoff Obstacle Clearance

Those videos are great, not 100% sure but I think they are applying 135 "requirements".

No, but I'd suggest not tempting physics, nature will not be fooled said Richard Feynman.

GF

Most AFM's have perf data in % gradient. If you look at a Jepp SID, there is a climb rate / ground speed table on it. To determine the % gradient, look at the VSI number listed under the 100kt Groundspeed column. Mentally divide that number by 100 and that will give you the required climb gradient in %.

Example: 575 ft/min = 5.75%

Remember that SID's and ODP's assume ALL engines are running.
See AIM 5-8-2 and AC 120-91 for further info.

Correction on AIM Reference: 5-2-8 :rolleyes:

Heck yeah on the e6b technique. I love using that thing.

The problem with a required VVI is that it is too late after you take off to find out that you can't make it. You need to have a chart in your AFM that tells you climb gradient (%) based on certain conditions. At my airline, a bunch of us prior Air Force heavy guys brought this up and the official answer was: "Yeah, we were kind of thinking about that but we don't have one for this aircraft." OK, I'll just fly the Jepp engine out procedure and "believe".

My favorite way is to look at the runway analysis and weigh less than that. For the 121 guys, most airlines use runway analysis. For the corporate guys, I highly recommend it as alternate single engine procedures enable you to weigh more at some of the more restrictive airports.

I second your idea. We use the Aircraft Performance Group software at our company and it is fantastic. It is plugged right into fltplan.com so all we have to do is select the flight, select "Use METAR" and enter the takeoff and landing weights and it spits out all of the information. For you 135 guys it even says the maximum weight allowed and gives you the reason why that is the max weight eg. structural limitation, climb limitation, field length etc. This makes it easy to put the correct max weight on the weight and balance forms. Really top notch program that I think makes us all safer.