The Jargon File (version 4.4.7, 29 Dec 2003):
pilot error
 n.
    [Sun: from aviation] A user's misconfiguration or misuse of a piece of
    software, producing apparently buglike results (compare UBD). ?Joe Luser
    reported a bug in sendmail that causes it to generate bogus headers.? ?
    That's not a bug, that's pilot error. His sendmail.cf is hosed.? Compare 
    PEBKAC, UBD, ID10T.
The Free On-line Dictionary of Computing (30 December 2018):
pilot error
    (Sun, from aviation) A user's misconfiguration or
   misuse of a piece of software, producing apparently bug-like
   results.
   E.g. "Joe Luser reported a bug in sendmail that causes it to
   generate bogus headers."  "That's not a bug, that's pilot
   error.  His "sendmail.cf" is hosed."
   Compare UBD.
   [Jargon File]
   (1994-12-05)