Second Segment Climb Gradient


Just wondering if anyone happens to have information on second segment climb for the following aircraft:

Lear 45 with the BR mod
Hawker 700 & 800A
Piaggio P180
King Air 350

We were delayed in EGE due to a low overcast and of course when we got back the boss was asking about numbers for these aircraft. Our chief told him an F-16 would do it. :wink: Thanks in advance for any input!



The King Air 350 and the P180 are part 23 certified airplanes. Only part 25 airplanes are required to have minimum climb gradients.


Really? I didn’t know that. What the deal with FAR 23.57. I really don’t know, I’ve never flown a part 23 a/c.


The C560 will rarely make the climb on the Gypsum3 deparure. This forces us to get a VFR climb to 15,000 which can obviously be pretty restrictive. It may be an interesting winter. :unamused:


The King Air 350 was certified under Part 23 Commuter Category. This allowed Beech to certify it under the less stringent Part 23. However, because the 350 has a greater than 12,500 lb. MTOW its performance must adhere to Part 25 standards…requiring the same perf calculations, Vspeeds, accel-go, accel-stop, second segment, etc.


That’s just one of the criteria for certification that a manufacturer must conduct flight testing and publish performance data for in those segments of operation.

And of course you’ve flown a Part 23 airplane…what was the first airplane you ever flew?..


Yeah…EGE can be tough…not as tough as ASE, but challenging just the same. As for the aircraft you mentioned…forget the Hawker 700/800…worse than the C560. I would have to visit with a friend of mine who flew the 350 to see of he still has his books. And cfijames could probably help you out with what the P180 will really do OEI…


Yes you’re right I have. I should have said I’ve never flown a commuter category part 23 a/c, such as a King Air.

BTW it was a C-172



As a non-commuter, <12,500lb, part 23 certified airplane, the Piaggio is not required to have any better performance engine out than a light twin. Some light twins are incapable of climbing at all on one engine.
Granted, from my training experiences, the airplane performs quite adequately on one engine, but loosing a motor out of Aspen is dangerous for nearly any airplane. We, as well as NetJets and others I’m sure, have a VFR escape maneuver out of ASE should we lose an engine. Basically it requires a tight turn to stay in the valley and flying down the valley towards lower ground. Winter brings cold temps and better performance, but also the risk of needing to use the anti-ice equipment, which robs the engines of power.


That’s understood…I was just thinking that you could run some numbers for YakDriver as your P180 AFM has the charted data for OEI second segment eventhough you’re not required to calculate it… :wink:


That sounds like a lot of work… :confused:
Now where did I put that shmegin AFM?..

On second thought, I’m pretty sure second segment climb gradients aren’t even in the AFM. We just have the regular rate of climb graphs.


Well that is good to know. Now does anyone know anything about the Lear 45? Thanks for the input.


My bad…I should have said OEI climb charts…“second segment” is Part 25 perf stuff… :unamused: :blush:

Sorry YakDriver, I’ve lost touch with a couple of guys that flew a 45…One went to US America Ways, and the other went to a DA900 somewhere…


Actually, the Kingair 350 has second segment climb charts in the POH. Not sure if this applies to all commuter cat. airplanes or not. As soon as I figure out how the hell to read them , I’ll get back with some numbers.


Yes, Part 23 “Commuter Category” certified airplanes must adhere to Part 25 performance standards…which is where the 350 falls. The P180 does’nt.


I would really like to know more about this, as I have heard of it, but never seen an example of it.

As a detail, I wonder if the charts take into account fuel on board. It seems this may make a huge difference in aircraft meant for long and ultra long range missions. I know from experience for example that the Bombardier Global 5000 performs spectacularly under a light load, considering it can carry like 35,000 lbs of fuel. I am told on a short light hop, the FD will command 40 degrees or more nose up.

I would like to see a chart from any aircraft if one could be located.



Engine inoperative climb charts for multiengine airplanes take into account; temperature, pressure altitude, gross weight, wind component, engine anti-ice, etc. Then there are different versions of these charts for various flap settings, 1st, 2nd, and final climb segments.

Most Part 25 airplanes have multiples of charts/graphs to derive climb gradients. The airplane that I fly for example has 15 pages of charts to figure it all out from.


One more thing to remember for part 91 operators once you are past the second segment altitude you are allowed to figure any remaining climb gradients specified using all engines. Not recommended when the weather is bad, but it is legal. Nothing says you can’t figure out your own “bail out” procedure either. If the weather is halfway decent you can get the sectional chart out (pre-flight of course) and find out which way the creek flows for instance.

This past summer at the annual fun in the simulator at Flight Safety the instructor picked EGE for our high/hot day. It had been years since either of us had been there for real, the graphics on the old simulator had been upgraded and were quite realistic. I forget the actual conditions but at about 75 degrees F the G2 could get out and fly about 2:30 or so. That’s figuring a single engine climb to the top of the required climb gradient. The other thing the instructor pointed out was that in any higher performance airplane following an engine failure at V1 or shortly thereafter you will NOT be able to successfully circle in the valley and return for an immediate landing.

We all remember from years gone by that the stalling speed is higher the more bank you have, but do you know why 15 degrees of bank is used following an engine failure on takeoff? VMC? no. Buffer above stall speed? no. Something I learned in this same session, 20 degrees of bank has half the lift of 15 degrees. Too much bank you won’t climb, that is why you can’t circle within the valley at EGE on one engine.

Play it safe,