Chapter 7 Post

This chapter talks about a MD-88 aircraft striking the approach end of a runway  with its main landing gear and narrowly escaping a catastrophe.  The NTSB found that one of the major contributing factors for this accident was the fact that the captain had contact lenses that weren't approved by the FAA for pilots.  These lenses created an optical illusion for the captain where he couldn't quite tell how fast he was descending.

Though mechanical failure was in no way to blame for this accident, there was an aircraft factor I found particularly interesting.  The crew had a vertical speed indicator that was labeled as "noninstantaneous."  This meant that the indicator could have a lag of up to 4 seconds before displaying accurate climb or descent rate.  The indicator could have been updated to show instantaneous rate if it was integrated with the inertial reference unit.  The NTSB determined that the lag time in the VSI also contributed to the accident.

Walters, J., & Sumwalt, R. (2000). Aircraft accident analysis final reports. New York: McGraw-Hill.