Air Force Missed Approach Climb Gradients
 

Hello All.

I have a couple questions for someone that is really smart on Air Force regulations. Having been a former Army pilot, I lack the experience with how the Air Force operates. My question is about Missed Approach Climb Gradients. We were evaluating an airfield as an IFR alternate for our flight and the ILS has two sets of minimums. The lower minimum is only authorized if the aircraft can maintain a specific missed approach climb gradient.

Question #1. When looking at the missed approach climb gradient, do I evaluate this based on all engines operating or on one engine inoperative for planning?

Question #2. The POH only has missed approach climb data for one engine inoperative. Can we just use two engine NORMAL TAKEOFF climb data since we do not have two engine missed approach data? We do have balked landing data for two engines, but depending on the temperatures, we may not meet the climb gradient. So basically, the ONLY data we have that allows us to make the gradient is a two engine normal takeoff climb chart and that is what we are being told to use for missed approach planning.

Any input is appreciated. If you have a specific reference that would be even better.

Thanks

Hard to supply you with specifics because you provided zero specifics. Maybe who you fly for, where you are flying, and what aircraft you are flying.

#1: use whatever you want/your rules say. Regardless, if you want to not hit something on the missed then you would use one engine missed data.

#2: Since your POH has missed approach climb data for one engine inoperative then their is your answer.

I am guessing your airplane doesnt meet the climb gradient OEI and you want to still do the approach. If the weather is IMC then you should have OEI performance. If the weather is VMC then who cares.

Negative. Just because it's VMC doesn't mean there will be a nice valley for you to visually fly through to escape the terrain. You will only be able to see the ground right before you impact it with OEI. You need to be legal/safe whether IMC or VMC.

I am not aware of any single engine missed approach requirements. At that point you are an emergency. I would never plan to shoot an approach to mins single engine.

I fly a thrust deficient aircraft as well. If you are concerned about getting in there, the real concern should probably be how are you going to get out if you lose a motor on takeoff. I think that is a much more likely scenario. On approach your engines have already served you well for a couple of hours.

Your references should be 11-202V3 and your aircraft's V3.

I do agree with Ohio's assessment of VFR/IFR if not his use of their/there.

I do disagree with KME... VFR and IFR rules are different for a reason. Gentle bank into good engine and spiral your way up if that magical valley does not appear in front of you. Not ideal, but completely legal.

7.8.2.2.1 below seems to indicate that you still have a min requirement when OEI even though you may get relief of up to 48'/NM...

AFI11-202V3 7 NOVEMBER 2014

7.8.2.2. Multi-Engine Fixed-Wing Aircraft. Using thrust available when starting the
approach (AEO or OEI), ensure the aircraft can meet 200 ft/NM or the published missed
approach climb gradient, whichever is higher, to an appropriate IFR altitude (T-1).

7.8.2.2.1. If unable to meet published missed approach climb gradient OEI, and
operationally necessary, the MAJCOM/A3 may authorize subtraction of up to
48’/NM from the missed approach climb gradient. This authority may be further
delegated, but may not be delegated to the respective aircrew for which the waiver
would apply (T-1).

Good on you KME. I was just too lazy to look it up.

Sort of agree with your statement above but not applicable. VFR/IFR is not the same as VMC/IMC. If you are operating under INSTRUMENT FLIGHT RULES (which we nearly always are in the USAF), you must meet the same requirements whether IMC or VMC.

That is why I specifically went with the R and not the C. Rules are the basis of this discussion.

My aircaft often operates VFR.

KME.... That is the only thing they have given us as well. Where it says that "using the thrust available when starting the approach (AEO or OEI)". The argument is that we never "Plan" to make an approach with an engine out and so we will use AEO data for all missed approach planning. My argument then is that if we never plan for an engine out approach, why do we always plan for an engine out at V1 takeoff? And by default, if we have an engine failure at takeoff we will then be making an engine out approach. It is the opinion of the FAA that an engine out arrival is more likely than an engine out takeoff because during the takeoff there is such a narrow window for the engine failure to occur but for the arrival you have the entire time that you are airborne for there to be a problem.

So I guess what I am seeing is that there is no "Official" guidance from the Air Force about if you have to plan for a missed using AEO or OEI other than you have to meet the requirement for whatever condition you are in when you start the approach. I guess then it would be the Unit SOP's to regulate on what you do for planning purposes.