STHOOTP Statistics

Date:         23 Nov 96 03:36:21 
From:         Andrew Goldfinger <Andy.Goldfinger@jhuapl.edu>
Organization: apl
References:   1
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	I previously posted a request for reports of STHOOTP ("Scare The Heck
Out Of The Passengers") incidents.  I received 10 replies, of which 9
were useable (one did not report total number of flights).  Bear in mind
that this is an unscientific survey.  One person, for example, included
flights from the 1950's.  In addition, there was variablity in just what
was considered frightening.  In all cases I took the reports as given,
that is: if it was reported as frightening I recorded it as such.  For
what they are worth, the data (including my own estimate) are as follows:

Flights	  Incidents     Percentage

592	           3	                0.51
170	           3	                1.76
200	           0	                0.00
600	           2	                0.33
200	           1	                0.50
1300	         2	                0.15
100	           1	                1.00
50	             0	                0.00
45	             0	                0.00
2600	         5	                0.19

In total, 17 STHOOTP incidents were reported in an estimated 5857 flight
for an overall incidence of about 0.3 percent.

The breakdown of incidents is as follows:

turbulence:     10
wake vortex encounter:    1
sudden maneuvering:     2
lightning strike:         1
aborted landing:       1
sudden unexpected zero-zero landing:     1
electrical failure:     1

What do we conclude?  Hard to say, but I think the following observations
are reasonable:

1.   STHOOTP incidents are infrequent, but not rare.  The average flyer
is likely to experience at least one frightening incident during their
lifetime.

2.   Turbulence is the most common cause.

I welcome any further reports from readers.