Discussion about the uses of flaps during mountain SAR flying. What are you doing? I tend to not use flaps when Im flying the Departments 206. The Dept 206 has a vortex generator kit installed which makes a huge difference in stalling speed. Without flaps I am still maintaining about 85-90 kts during a search. And I wouldn't get any slower than that if I had flaps in. About the only time I really drop in the flaps is if I am flying down a canyon or need to control my speed. When I attended the CAP Mountain Course, we generally put in about 10 degrees but I dont recall any hard and fast rules about it. A Mission Mentor pilot I trained with didnt discourage the use of flaps, but we had several discussions about wing loading, etc when using flaps.
I usually use 10 degrees in the 182 same as doing 90kts everywhere else. It seems like having a notch of flaps in at 90 knots lets me drop the nose a bit and just feels more comfortable. With our limit of 1000' agl it is hard to find a canyon around here (TN) that can be searched.
Capt Borsari hit it. The real benefit I get with 10 degrees of flaps in our U206H is not so much slower stall speed, but rather it drops the nose nicely, and improves the sight picture.
Dropping the nose to a more flat attitude is the reason that CAWG teaches this technique. I happen to be one of the Mt flying mentor pilots in CAWG and we have taught it that way for some time. It also helps climb attitude if power needs to be added in a hurry: which occasionally happens in the Sierras. The canyon turn that we teach is helped by a notch of flaps.
YMMV: some of these techniques vary with the pilot. I happen to have more than 300 hours of search time in the high rocks and I use these techniques. Not saying that they are absolutely correct, they just seem to work for me.
My view is that it is a personal choice balancing the terrain and the passengers' stomachs. Bob, in the MFC training, Dave W. was fine with flaps and hard slips down canyons to keep the same altitude AGL giving the scanners the same POD. I liked that, but I am biased, having cut my teeth on flapless taildraggers. I noticed when flying with you, you seemed to be more in favor of set-and-forget, the smooth, not too much slippage approach. I can run with that as well. Having been in the back I can see the pilot's idea of maneuvering the plane is not always so much fun for the back seat.
Even without slips, the great big barn doors on the Cessna are a great airbrake if you have to go down a big canyon, a good place to find an aircraft. So pointing the nose down without much flap means roaring by at a great rate of knots - not so good for the scanners. In another post I actually suggested going down steep canyons with full flaps and 70kts, but I got chewed out a bit because of the airspeed. I have tried it a few times and personally I think it is not easy to scan effectively down a canyon at 90kts. I prefer to let the aircraft glide down gently under a maximum lift, maximum drag configuration. That's just me, but I when you get into more maneuvering I can also appreciate the argument for just setting 10 degrees and not touching anything. Not sure if there are any hard and fast rules amongst terrain. Probably just comes down to giving the scanners a good ride and a good chance at locating a target while being sensible and safe.
Probably just comes down to giving the scanners a good ride and a good chance at locating a target while being sensible and safe.
Thats the biggest key. When your crew is scared to death or barfing, your just wasting gas. I do a lot of mountain flying at work searching around for .....stuff. In the Sierras, the turbulence comes out of nowhere. You fly around a finger or a ridge line and next thing you know, you just smacked your head against the door because a gust just hit you. By the way, I am an advocate of if your going to fly low level in the mountains you should have a helmet on. Even if its just a Protec. I have one where I cut out the ear section so my headset fits right over the top of the helmet and the ear cups fit in the area I cut out with a Dremmel tool. I actually made it for my NVGs because my helicopter helmet was to bulky for the plane. I had myself knocked senseless once on a flight and had knot on my head from head hitting the door frame. The ride before and the ride after was like glass.
But I digress....
I like to keep my speed up at about 85 - 90. The TC206 is a heavy airplane, but it has sufficient power to get you out as long as you don't let yourself get in to far. If the observer sees something, I can maneuver and the slow up a little. When flying down a canyon I definitely go full flaps to keep my speed under control. But you have to be on top of your speed because as soon as you level out at the bottom, you will stop flying really fast if you leave your flaps down and don't get on the throttle at the right moment. I try to anticipate and at least have my flaps at 20 before I start pulling the nose up. In a 206 at full flaps doesnt climb out well.
I remember the discussion we had about full flap side slips. My concern with that was although the POH doesnt prohibit it, slow flight, low level, in the mountains in uncoordinated flight just seemed a little much. Especially with canyon turbulence could be waiting just around the next rock. I have done it and it was a very uneasy feeling. I spoke with some fire pilots who skim the tree tops all day long and their eyes got pretty big too.
Now if I was in the lower foothills, below 3000 ft or so, but not heading down the granite faces of the Sierra's. 70 kts is landing speed and you are really teetering on the edge of disaster I think. Even a small gust could cause you to stall. Thats why I really like searching high mountains in the early morning. The light isnt great but the ride is better. Not like a certain mission I was on where they had us searching at 13K+ in mid afternoon! And the mission managers could understand why the pilots were upset!
I agree there are no hard and fast rules. And a 206 at full flaps and a 182 at full flaps are different animals.
QuoteBy the way, I am an advocate of if your going to fly low level in the mountains you should have a helmet on. Even if its just a Protec. I have one where I cut out the ear section so my headset fits right over the top of the helmet and the ear cups fit in the area I cut out with a Dremmel tool. I actually made it for my NVGs because my helicopter helmet was to bulky for the plane. I had myself knocked senseless once on a flight and had knot on my head from head hitting the door frame. The ride before and the ride after was like glass.
GA aviation helmets? I sense a place for entrepreneurship. have the mic and headset built in with the appropriate phone and mic pins.
heck I could have used one in the pattern earlier today...
Quote from: SABRE17 on December 31, 2010, 08:26:39 PM
QuoteBy the way, I am an advocate of if your going to fly low level in the mountains you should have a helmet on. Even if its just a Protec. I have one where I cut out the ear section so my headset fits right over the top of the helmet and the ear cups fit in the area I cut out with a Dremmel tool. I actually made it for my NVGs because my helicopter helmet was to bulky for the plane. I had myself knocked senseless once on a flight and had knot on my head from head hitting the door frame. The ride before and the ride after was like glass.
GA aviation helmets? I sense a place for entrepreneurship. have the mic and headset built in with the appropriate phone and mic pins.
heck I could have used one in the pattern earlier today...
Sadly, its already been done :'(
yeah, Google crushed many dreams... few keywords and BAM, hopes dashed
I noticed no one mentioned density altitude. Aircraft performance is based on density altitude and weight. Climb performance is the most important thing in mountain flying at high density altitudes (summer). Flaps 10 will give you a better stall margin at 80-90 kt. since stall speed doesn't change until the really high altitudes around 14000' density altitude. I fly with flaps 10 so if I screw up or need to climb in a hurry. I don't have any extra drag to get rid of before I can climb. Here in Colorado we regularly fly above 12500' pressure altitudes on mountain searches. Fly 182s.
Great and very interesting discussion about the use of flaps.
I would add another factor that you should consider when using flaps in any flight regime: The Flight Load Limit is reduced from 3.8g to only 2.0g when the flaps are down. This is from the U206G and 182P/Q/T Cessna POH/PIM and does not differentiate between 10/20/or more degrees.
One heavy duty gust with the flaps down and the load limit may be exceeded.
Simon, any chewing out comes from a place of Love :-*