IFR Take Off Considerations

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Posthumane
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Re: IFR Take Off Considerations

Post by Posthumane »

digits_ wrote: Sat Oct 02, 2021 8:55 am Correct me if I am wrong, but single engine in a twin you do not need to meet the climb gradients on the charts, you only need to make sure you don't hit anything.
My initial thought was that you still need to outclimb the obstacle clearance surface, which I thought was 48'/NM less than the published climb gradient but it turns out I was wrong and it's 24% less. That can be a big difference. I found this site provided some good reading on the topic:
https://code7700.com/doa_strategy.htm
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NotDirty!
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Re: IFR Take Off Considerations

Post by NotDirty! »

For a private flight, there is no requirement to meet terrain clearance with OEI climb performance. If the engine quits on a single, you are definitely not out climbing the terrain, even in Saskatchewan! This is one of those places where your risk assessment has to decide whether it is an acceptable risk for you and your family.

So the question on a flight test, the legal answer may be yes you can legally depart, but the practical answer is much more complicated.
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Eric Janson
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Re: IFR Take Off Considerations

Post by Eric Janson »

oldncold wrote: Fri Oct 01, 2021 11:13 pm did my first ifr ride over 30years ago with ernie pool tc inspector great guy full of tips on ifr. during the ground portion of my ride
gave me a scenario of the rutland one departure out of ylw, which was. it's 200ft 1/2 mile can you depart in your twin Comanche. I knew the answer was yes ernie then said you are now at 600ft agl and your engine fails. what is the climb gradient required and environmental conditions your now single engine. Climb in ft per min. never forgot ernies wisdom of that lesson that I would be royally hooped. ride went well and he signed off my ir it. so to original poster make sure ya look up the climb gradient on the departure. to make sure that if the poop hits the fan you can meet the ft per nm or min in those imc min conditions
Thanks for raising an extremely valid point.

In the Airline World we have a published engine failure procedure for every runway.

What people don't realise is that it only covers you to 1500' AAL. This is quite often still below MSA leaving you to figure out how to avoid terrain.

I've been in a situation departing at night from an unfamiliar airport where the normal departure and the go-around procedure was a right turn and the engine out procedure was a left turn towards terrain that was showing with the terrain mode selected on the navigation display. All 3 of us agreed that it would be a right turn after take-off.
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fish4life
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Re: IFR Take Off Considerations

Post by fish4life »

Eric Janson wrote: Mon Oct 04, 2021 12:25 am
oldncold wrote: Fri Oct 01, 2021 11:13 pm did my first ifr ride over 30years ago with ernie pool tc inspector great guy full of tips on ifr. during the ground portion of my ride
gave me a scenario of the rutland one departure out of ylw, which was. it's 200ft 1/2 mile can you depart in your twin Comanche. I knew the answer was yes ernie then said you are now at 600ft agl and your engine fails. what is the climb gradient required and environmental conditions your now single engine. Climb in ft per min. never forgot ernies wisdom of that lesson that I would be royally hooped. ride went well and he signed off my ir it. so to original poster make sure ya look up the climb gradient on the departure. to make sure that if the poop hits the fan you can meet the ft per nm or min in those imc min conditions
Thanks for raising an extremely valid point.

In the Airline World we have a published engine failure procedure for every runway.

What people don't realise is that it only covers you to 1500' AAL. This is quite often still below MSA leaving you to figure out how to avoid terrain.

I've been in a situation departing at night from an unfamiliar airport where the normal departure and the go-around procedure was a right turn and the engine out procedure was a left turn towards terrain that was showing with the terrain mode selected on the navigation display. All 3 of us agreed that it would be a right turn after take-off.
Everywhere I’ve worked always has procedures all the way up to whatever the safe altitude is not just 1500’ since that’s pretty useless
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dialdriver
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Re: IFR Take Off Considerations

Post by dialdriver »

fish4life wrote: Mon Oct 04, 2021 4:11 am
Eric Janson wrote: Mon Oct 04, 2021 12:25 am
oldncold wrote: Fri Oct 01, 2021 11:13 pm did my first ifr ride over 30years ago with ernie pool tc inspector great guy full of tips on ifr. during the ground portion of my ride
gave me a scenario of the rutland one departure out of ylw, which was. it's 200ft 1/2 mile can you depart in your twin Comanche. I knew the answer was yes ernie then said you are now at 600ft agl and your engine fails. what is the climb gradient required and environmental conditions your now single engine. Climb in ft per min. never forgot ernies wisdom of that lesson that I would be royally hooped. ride went well and he signed off my ir it. so to original poster make sure ya look up the climb gradient on the departure. to make sure that if the poop hits the fan you can meet the ft per nm or min in those imc min conditions
Thanks for raising an extremely valid point.

In the Airline World we have a published engine failure procedure for every runway.

What people don't realise is that it only covers you to 1500' AAL. This is quite often still below MSA leaving you to figure out how to avoid terrain.

I've been in a situation departing at night from an unfamiliar airport where the normal departure and the go-around procedure was a right turn and the engine out procedure was a left turn towards terrain that was showing with the terrain mode selected on the navigation display. All 3 of us agreed that it would be a right turn after take-off.
Everywhere I’ve worked always has procedures all the way up to whatever the safe altitude is not just 1500’ since that’s pretty useless
This doesn't apply to the original post.
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