Non-Tower Airports / Mountainous terrain

[Ol'Roy]

I was wondering if one of you part 91/AIM gurus could walk me through a few interview questions with regard to nontower airport considerations.

when they ask about departing from an uncontrolled field:

When do you follow departure procedures on the back of the airport diagram?
When can you turn?
What altitude do you climb to?
Operations when visibility is below landing minimums (part 91).
What considerations are there in mountainous terrain?...etc

Any other tricky questions/scenarios that you can think of regarding operations at non-towered airports.

Thanks in advance.

 

[avbug]

When do you follow departure procedures on the back of the airport diagram?

All the time. Why wouldn't you? There's no good reason not to fly the obstacle departure, given the opportunity, unless you're flying VFR and it won't fit your needs. Certainly in instrument conditions; fly the obstacle departure. That's why it's there.

When can you turn?

If in visual conditions, and not operating under Part 135 or 121, when ever you feel like it, consistent with safety. If in instrument conditions, then fly the obstacle departure proceedure. Turn when the proceedure tells you to turn.

What altitude do you climb to?

This is student-pilot basic. Look at the proceedure, and follow it. If you are in visual conditions, then climb as appropriate.

Operations when visibility is below landing minimums (part 91).

You can take off without any visibility restrictions in mountainous terrain at an uncontrolled field...but be certain you can meet the obstacle departure proceedure criteria, else you're taking an awfully large gamble.

Technically, if not in controlled airspace, IFR flight may be operated without a clearance, and without talking to a soul...there are plenty of places where this is certainly possible, although in many circumstances, unwise. You are not required to have a takeoff alternate, though you really should...and you really need to consider your climb gradient with an engine out. If you're flying single engine, then you need to consider what's going to happen to you if you have a problem of any kind...you may not like what you find out. In such a case, forgoing the flight completely is usually the best approach.

What considerations are there in mountainous terrain?...etc

Big, sharp, pointy rocks.

Fly the airplane the same as you fly in flat terrain. All the garbage about "mountain flying" is hype. The airplane has no idea if mountains are present; you should fly the airplane the same no matter where you go. Fly it according to the takeoff conditions that exist at the time of departure, calculate your performance, and plan your flight accordingly. The same things you've been taught to do, and had reinforced since you were a student pilot. No difference.

 

[Lead Sled]

Fly the airplane the same as you fly in flat terrain. All the garbage about "mountain flying" is hype. The airplane has no idea if mountains are present; you should fly the airplane the same no matter where you go. Fly it according to the takeoff conditions that exist at the time of departure, calculate your performance, and plan your flight accordingly. The same things you've been taught to do, and had reinforced since you were a student pilot. No difference.

Avbug...
Normally, I agree with you but not this time. if you "Fly the airplane the same as you fly in flat terrain" you can set yourself up for some serious issues - especially in light, normally aspirated aircraft. I'd venture to guess that most "flat landers" have never been taught to cross mountain ridges at a 45 degree angle or to fly on the upwind side of a valley. Crossing a ridge, head-on, in a low powered airplane is not smart. Most flat landers don't have to deal with density altitudes that can reach 9,000' or more.

Ol'Roy...
With the above exception, everything he says is spot on. There are special issues associated with operating in mountainous areas. There are some books on the subject. I believe the best one is Mountain Flying by Sparky Imason (I not positive of the title or the spelling of the author's last name).

'Sled

 

[avbug]

Avbug...
Normally, I agree with you but not this time. if you "Fly the airplane the same as you fly in flat terrain" you can set yourself up for some serious issues - especially in light, normally aspirated aircraft. I'd venture to guess that most "flat landers" have never been taught to cross mountain ridges at a 45 degree angle or to fly on the upwind side of a valley. Crossing a ridge, head-on, in a low powered airplane is not smart. Most flat landers don't have to deal with density altitudes that can reach 9,000' or more.

In flat land, we calculate takeoff peformance. In the hills, we calculate takeoff performance. Seems the same.

I believe most of the questions here regarded instrument flying, but either way...if one can't fly around rocks, it isn't a matter of needing additional training; it's a matter of weak skills and insufficient training in the first place.

An airplane has no idea what obstacles lie above or below. An airplane doesn't really know how close it is to trees, antennaes, mountains, or whatever. TAS increases at higher density altitudes, when indicated airspeed remains the same or is held the same.

Can a student pilot not read? Does not every private pilot manual talk about how to cross a ridge, and then advise crossing at a high enough altitude where it's never an issue?

The poster is asking about questions for a job interview; presumably he or she isn't a student pilot.

I fly some fairly serious contact work in very cut-up mountainous terrain at times, often loaded to the gills, almost always in strong winds and lowering visibilities. And a whole lot closer to the ridge than most. The truth is, I don't fly around hills any differently than I fly over a field, or at FL 410...it's all the same airmanship.

It's a little like a conventional gear airplane. A tailwheel airplane is no more difficult to fly, but it exposes poor habits and bad training. Flying around terrain may do the same thing. The flying is the same, but for those who don't exercise basic good airmanship to begin with, it can bite.

The fact remains, however, that the flying is the same.

 

[Ol'Roy]

Avbug,

These are, in fact, interview scenario type questions. It's been a long time since i've done any kind of part 91 flying and I'm trying to re-learn a lot of this stuff.

Sometimes asking a question here in plain language is easier than sifting through the FARs and AIM.

Thanks for your response.

 

[avbug]

True enough, and heaven knows I'm no expert on the best way to interview. My take on that would be to offer the most conservative viewpoint. If asked weather you should fly the departure proceedure, I believe the correct answer is yes, you should. In that, you're gauranteed the terrain separation. If queried, you can also address the need to substantiate single engine climb performance matching the obstacle departure, as part of the preflight planning.

Setting that as the basis of your response to the hypothetical interview questions, every answer then becomes the same; fly the departure proceedure. When to turn? Fly the departure proceedure. How high? Fly the departure proceedure. And so on. If there is no departure proceedure, then the conservative approach would be to insist on adequate visibility and clearance in order to maintain your own terrain separation.

My own viewpoint, especially in mountainous terrain, is that at night I consider it an instrument departure, and fly it as published. It's hard to go crossing ridges at angles and flying close to hills when you can't see them in the dark; it's easy to fly a proceedure because it doesn't matter where you are or what lies beneath; adhere to the proceedure, and your questions are answered in one fell swoop.

 

[Ol'Roy]

What about weather minima required for departure? I know part 91 you can do what you wish, but are there any good guidelines for an airport in this scenario?

 

[Sctt@NJA]

The problem with some mountain airports, towered or not, is that the IFR climb requirements can be almost impossible to meet when considering the loss of one engine.

Aspen comes up all the time at my company. We have company supplied wx minimums for departing Aspen which are designed to provide adequate room to manuever visually around or over obstacles.

But these wx minimums aren't as cut and dry as you might think. Weather can be very localized and even when the weather is fine at the field itself it may be IFR with obscured terrain 5 miles away in the direction you need to go.

So the deciding factor for daparting may boil down to your eye balls and what they see when looking around from the ground and your knowledge and familiarity with the local terrain. You will consider where the lowest terrain is, how to get there, what kind of room you will have to manuever ect ect ect. It really isn't as cut and dried as most people would like it to be.