This question came up in the comments and we wanted to share the information with our readers.

Q: I am a Mechanical engineer by education and trade, and therefore when we talk about the effects of temperature and pressure on altimeter readings, I can't resist the urge to try to rationalize the information discussed in a more technical manner (i.e. Hi to low, look out below). I understand the information presented, but was wondering if you could refer me to a source that goes into a little greater technical detail about the mechanics of pressure, temperature, and altimeter readings.

A: We contacted Peter Garrison of Flying magazine.  He recommended Fundamentals of Aircraft Flight and Engine Instruments by Jack Andresen, Hayden, 1969. The Library of Congress catalog number is 79-83293. Peter said he googled the title and came up with a number of returns, so per Peter there may be some copies available online.

Thanks to those who posted questions in the comments of the first post, please keep the ideas coming.

The question of how load factor on the airplane is affected during descent came up and is an excellent opportunity for discussion.  Any questions that our readers have can be addressed in a comment to this entry

The subjects of lift, weight, and load factors definitely create a never ending discussion.  In descents, keep in mind the airplane hasn't gone on a diet - it still weighs the same and it's flying in a straight line (only tilted downward).  So has anything changed?  The discussion of forces in descents in the FAA manual claims that after the flightpath is in a steady descent, the airfoil's angle of attach again approaches the original value, and lift and weight will again become stabilized.

Generally, as the airplane's line of flight is changed, there is some change in the load factor.  After the new line of flight (climb or descent) is stabilized, the forces equalize again, so we're back to about 1 g

Next time you are stabilized in a climb or descent, ask yourself whether you feel like you weigh more or less.  If you feel like you are at your normal weight, you and the airplane are at 1 g.