The shock limit for the Macintosh SE's internal hard disk drive is defined
as 40G -- for an inactive drive.
Apple tests the drive (only) to these limits:
Macintosh SE
------------
.25G, 3 to 300 Hz in the vertical direction (Z-Axis) only. Testing
frequency is held for 15 minutes at drive resonance as determined by
attached accelerometers.
Macintosh II
------------
.25G, 3 to 300 Hz in all three directions (X-axis, Y-axis, Z-Axis).
Airplane frequencies are at the higher end of the tested frequency
spectrum and could easily exceed those frequencies at higher amplitudes.