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I recently bought a used Cessna 182T (non-turbo) in Orlando Florida and flew it to Lima, Peru where I am currently based. I am a private pilot with 220 hours total time, (approximately 80 hours in the 182). I want to start doing some mountian flying in the Andes with the 182. However, I have no mountain flying experience. Also there is not much general aviation in Peru and none of it flying single engine pistons in the Andes. So far I haven't found an instructor who has mountain flying experience in my kind of aircraft. I would like to know what performance I may expect from my aircraft taking off from Altitudes of 8,500 ft and density altitudes of over 12,000 ft. My aircraft has a service ceiling of 18,000 ft but the POH only gives information for the aircraft maximum rate of climb at (3100 lbs) until a pressure altitude of 14,000 ft. The following questions are formulated considering I will fly the aircraft as a 2 seater (2800 lbs vs 3100 lbs), use a relatively long paved runway +9000ft long and field elevation of 8500 ft. I should have to clear terrain no higher than 11,500 ft for my flight and have no immediate obstructions after takeoff. 1. What is highest pressure altitude I should consider taking off from? 2. How high can I expect to climb with a temperature of +20C at the airport? 3. What can I expect my climb rate to be? 4. How do I calculate the service ceiling for my aircraft at a lower weight than MTOW? 5. Any tips, recommendations or suggestions? Thanks, Abel
I doubt you're still around, but I'll take a brief crack at this.
According to John Ecklabar (a Bonanza expert, but also knows his stuff aerodynamically), you can adjust handbook numbers for different weights using the following "rules of thumb":
1. Climb: the climb rate will increase about as much as your percentage under gross. So for 2800 lbs vs. 3100 lbs, you can expect the climb rate to increase by about 10%.
2. Takeoff roll: the roll will decrease by about the square of your percentage under gross. Using the same numbers, (2800/3100)^2 = 82%, so you could expect your take roll to decrease by about 18%.
3. Landing roll: here you expect a decrease about as much as your percentage under gross. Using the same numbers, you'd expect your landing roll to decrease by about 10%.
3. Cruise speed: You'll be faster a lighter weight, but the affect will be pretty small.
My overall assessment is that you can get your 182T to perform at the altitudes you're talkign about, but you need to be EXTREMELY conservative with weather, winds, temperatures, and loads to have anything approaching an acceptable risk level. And find someone very experienced in your local area who can help you work slowly into more challenging situations.
Just me, but for the sort of flying you're doing, I'd want a turbo.
I’m going to hope that in fact you are still around :-). I’ll try to comment on some of your questions.
Today (8/18/10) I flew a 2002 non-turbo non-pressurized fixed gear 182T, with a takeoff weight of 2775 lbs, from just higher than sea-level to 16700 MSL (the density altitude was about 18400 MSL), so this is just above the service ceiling. I was flying in the Sierras over the Mt. Whitney area in the early morning (about 8 am) in good weather with calm winds and great visibility.
This particular plane doesn’t have wheel pants and needs to have the cowl flaps open to keep the oil temperature below the top of the green in the summer, so the plane has more drag than usual.
As with your plane, the book for this plane does not go above 14000 MSL pressure altitude.
At the highest altitude, my climb rate was only 200-300 ft/min, even though the weight was less than the 3100 lbs maximum takeoff weight (MTOW), so in my experience the service ceiling is not particularly sensitive to weight (related to your Questions 3 and 4). In the last part of the climb, I could only make 78-80 KIAS, and that was with the prop at max rpm.
Related to your Question 5, here are some suggestions beyond what Mark said (and I hope I am not insulting your intelligence – after all you did accomplish a flight from Orlando to Lima):
--If you are based at a high-altitude field make sure to use the high-altitude takeoff and landing procedures (mixture adjustment).
--You will be in slow flight with a high angle of attack, so fly accordingly (gentle turns, keep the ball centered, etc). Granted it's not extreme slow flight (50 KIAS stuff) but still.
--You didn’t mention it, but I’m assuming your plane is not pressurized. Consider adjusting the oxygen flow to keep your oxygen saturation at about 90% (a compromise which helps to keep you out of hypoxia but doesn’t needlessly waste oxygen). I found that the best way to do this is to get a small pulse oximeter and check the oxygen saturation every 10 minutes or so. If you are using a cannula, remember to breathe through your nose and not your mouth. This sounds silly but it is easy to forget when you get distracted with other tasks.
Hope everything works out.
Take extra care to avoid activities that might detract from flying.
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