Advanced search  
Pages: [1]   Go Down

Author Topic: FAQ: Climbing for a look around / Physiology of altitude  (Read 5390 times)

Walter Runck

  • T3
  • ***
  • Posts: 117
FAQ: Climbing for a look around / Physiology of altitude
« on: March 23, 2011, 09:04:46 PM »

OK, here's a corner of the forum that hasn't been poked in a while, so I'll give it a shot:

If AE and FN wanted to climb above the clouds to try and get a navigational sight on the overnight part of the flight, what would have to be considered in terms of time, speed, distance, fuel, oxygen, weather, etc.?

For starters, how about a climb on course at a maximum fuel efficiency rate of climb from their cruising altitude at 1400Z to 19,000 feet for 10 minutes straight and level, then a return to cruise altitude at the most efficient rate of descent?

I'm not a pilot or an aerographer, so I look forward to some educational input from those who are.  Can someone describe the most likely profile, the pros and cons of such a maneuver, and whether it would make sense to try it if you hadn't been able to determine your position, SMG, CMG and winds aloft due to overcast skies?
« Last Edit: July 16, 2012, 08:22:05 PM by J. Nevill »
Logged

pilotart

  • TIGHAR member
  • *
  • Posts: 139
Re: Climbing for a look around
« Reply #1 on: March 23, 2011, 10:26:19 PM »

The primary problem with that climb would be the increased likelihood of hypoxia.

They carried no oxygen and even at the recommended altitude of 10,000; Fred as a cigarette smoker would have already suffered enough effects to reduce his night-vision ability.  Hypoxia is not easy to detect, but it can cause you to have difficulty in simple navigation after a long flight at relatively high altitude and that could have contributed to their problems in locating Howland and the Itasca.  Don't know what cruise altitude Fred was used to in the PanAm Clippers, but you can be sure that oxygen was available for him at higher altitudes.

A piston powered aircraft does not usually gain very much in range at higher altitude and at the much heavier weight that they were operating at, they may have lost range by climbing higher than the recommended 10,000'.

Headwinds tend to increase at higher altitudes and in the trade-wind areas of the Northern Hemisphere, you will often see a fairly strong East Wind at one or two thousand foot cruise altitude, while a strong wind from the West will be found at ten or twelve thousand.

Art
Art Johnson
 
Logged

Martin X. Moleski, SJ

  • Administrator
  • *
  • Posts: 2901
Re: Climbing for a look around
« Reply #2 on: March 24, 2011, 08:17:32 AM »

The primary problem with that climb would be the increased likelihood of hypoxia.

They carried no oxygen and even at the recommended altitude of 10,000, Fred as a cigarette smoker would have already suffered enough effects to reduce his night-vision ability. ...

It seems to me the modern recommendation is not to exceed 5,000 feet at night in an unpressurized aircraft without supplemental oxygen because of the effect of hypoxia on night vision.  "Hypoxia can cause rapid deterioration of night vision, even at altitudes as low as 5,000 feet msl" (AOPA Online).
LTM,

           Marty
           TIGHAR #2359A
 
Logged
Pages: [1]   Go Up
 

Copyright 2018 by TIGHAR, a non-profit foundation. No portion of the TIGHAR Website may be reproduced by xerographic, photographic, digital or any other means for any purpose. No portion of the TIGHAR Website may be stored in a retrieval system, copied, transmitted or transferred in any form or by any means, whether electronic, mechanical, digital, photographic, magnetic or otherwise, for any purpose without the express, written permission of TIGHAR. All rights reserved.

Contact us at: info@tighar.org • Phone: 610-467-1937 • Membership formwebmaster@tighar.org

Powered by MySQL SMF 2.0.15 | SMF © 2017, Simple Machines Powered by PHP