Pt. 91 Climb gradient

[semperfido]

Just call Jeppesen and ask for Ops Data. There is a short questionair to fill out and a few days later you get your alternate procedure.

'Sled

what is jepps alternate proc for ASE?

 

[Ty Webb]

You guys are professional pilots, right? You're supposed to know this stuff.

It's not under 91, it's under Part 25, and if you are flying an aircraft certified under this part (ie Transport Category Turbojet > 12,500 MTOW) then you certainly do have to comply with required climb gradients under 91, 135 or 121.

As for an Obstacle DP, you either have to comply with the published procedure, or have determined an alternate means of compliance.

Sheesh.

 

[Lead Sled]

OK I have a flak jacket on now. If the WX is IFR then you must be able to comply with the gradient of the SID 91 or 135. Correct? Please correct me if I am wrong. If I am wrong so be it, I aint a changing!

Flak jacket not required. Yes, you must be able to comply with the gradient of the DP regardless if you are operating under Part 91, 135 or 121. Period. Where most guys get wrapped around the axle is that they interpret that to mean that they must be able to do it after they have lost an engine. That is not correct. There have been many good threads and posts on this very topic and it has been beat to death.

Odd as it seems, Part 91 there is no specific reg to prevent you from launching IFR when you can't make the gradient single engine. That being said, I know of a Challenger crew that got clobbered after flying to the east coast from a certain airport in CO. When they landed, a fed met them and asked 'what did you weigh at takeoff'? Both crew got popped with 91.13 (the careless and reckless thing).

I had also heard of that aviation urban myth. The story, as it is told, is a myth. There is nothing illegal, immoral or fattening with operating above your "single-engine DP climb gradient" weight. Aspen 121 operators do it routinely. They have alternate procedures that allow them to safely do this. Again, this has been discussed on this forum before.

Common sense and the desire for self-preservation will tell you that you have to be able to keep your nose out of the dirt in case you lose an engine. Many good aircraft simply don't have the performance to fly out of airports like Aspen with anything approaching a useful payload and make the climb gradients specified in the Lindz4 after the loss of an engine. This is where the alternate procedures provided by Jeppessen OpsData and others come in. It gives you a legal alternative to the published departure procedure IN THE CASE OF AN ENGINE FAILURE OR OTHER EMERGENCY THAT WOULD KEEP YOU FROM BEING ABLE TO MAKE THE CLIMB GRADIENT SPECIFIED IN THE DP. Remember, climb gradients specified in DPs are based upon the operation of ALL engines.

I've got a question for you guys that are using your takeoff performance data to generate single-engine performance numbers for an airport (ASE) at nearly 8,000' msl and a DP climb gradient requirement to 14,000' msl. How are you coming up with valid numbers? (Please take a second look at the definitions, notes, stated configurations, stated conditions, etc. on your specific charts before you answer.)

'Sled

 

[HMR]

what is jepps alternate proc for ASE?

It's a DME arc off of DBL that brings you down the valley and ends in a hold just west of LINDZ. I plotted the waypoints on a VFR chart and connected them with a line. Took about 15 minutes with MicroSoft Paint. We keep it handy on ASE departures. It's easier/safer to use than the ops data alone.

 

[HMR]

I've got a question for you guys that are using your takeoff performance data to generate single-engine performance numbers for an airport (ASE) at nearly 8,000' msl and a DP climb gradient requirement to 14,000' msl. How are you coming up with valid numbers? (Please take a second look at the definitions, notes, stated configurations, stated conditions, etc. on your specific charts before you answer.)

I knew that was coming. Can't wait to read the answers.

Good job 'Sled.

 

[G100driver]

Ain't touching that one!!!

This is entire reason for turn procedures and alternate DP's!

 

[rice]

I've got a question for you guys that are using your takeoff performance data to generate single-engine performance numbers for an airport (ASE) at nearly 8,000' msl and a DP climb gradient requirement to 14,000' msl. How are you coming up with valid numbers? (Please take a second look at the definitions, notes, stated configurations, stated conditions, etc. on your specific charts before you answer.)

'Sled

Don't have the manuals handy right now but I'm "guessing" that it probably has something to do with a 1500' reference.
Should make for some interesting answers from the group.

'Sled, do you guys ever shoot the GPS Z or Loc/DME 15 ??

 

[johnny taliban]

I'll take a stab at that question. I believe that the correct answer is to go to your performance charts and determine your performance from 14,000 feet instead of 8,000 feet. The numbers you get off the tables only guaruntee single engine performance to 400 feet agl, therefore using the numbers from your 8,000 feet page will NOT provide you the obstacle clearance (14,000) that you need coming out of Aspen.

then again,I could be wrong
Johnny

 

[Lead Sled]

I'll take a stab at that question. I believe that the correct answer is to go to your performance charts and determine your performance from 14,000 feet instead of 8,000 feet. The numbers you get off the tables only guaruntee single engine performance to 400 feet agl, therefore using the numbers from your 8,000 feet page will NOT provide you the obstacle clearance (14,000) that you need coming out of Aspen.

Johnny, the answer that you gave is typical of the normal responses that most pilots would give. However, there are several reasons you cannot use AFM 2nd segment climb data in meeting TERP's (departure procedure) criteria.

First, all the one engine-out climb flight path data (1st, 2nd, and final segment climb charts) are only good to 1,500 above the runway and CANNOT be used to the heights demanded of certain DP's such as is the case of Aspen’s LINDZ4 departure - 7,820 ft to 14,000 ft. As you said, 2nd segment climb data is generally only valid to 400 ft above runway - the point where 2nd segment ends.

Second, the differences in climb terminology. Most 2nd segment climb gradient charts in AFM's give the available NET climb gradient so that when you apply this to the flight path charts or computer program you get a resulting NET flight path. TERP's climb requirements are based on actual performance, NOT an already an already reduced NET climb gradient.

Additionally, there's the consideration of 5 minute limitation on takeoff thrust. Many DP's require climb gradients to significantly high altitudes that would exceed the limitation on takeoff thrust, not to mention a shallowing climb gradient due to density altitude changes as you climb. (6000’ worth of change in the case of Aspen.)

Remember if you try to use 2nd segment climb charts, you'll only achieve that climb gradient if you keep V2, takeoff flaps, and takeoff thrust and that climb gradient is generally valid only at 400 ft above the runway. It can not be extrapolated beyond that.

'Sled

 

[some_dude]

Under 91, you do need to comply with the gradient with all engines operating (duh!). There is no specific requirement to comply with the gradient with an engine inoperative.

If an engine fails and you crash into the obstacle then you will be violated for being "careless and reckless."

Keep in mind that I am talking strictly about regulations, not necessarily about what is safe or smart.

Lead and I have already beat the 135 issue to death in another thread. I'm staying away from that one.

OK I have a flak jacket on now. If the WX is IFR then you must be able to comply with the gradient of the SID 91 or 135. Correct? Please correct me if I am wrong. If I am wrong so be it, I aint a changing!