(a) When an ATC clearance has been obtained, no pilot in command may
deviate from that clearance unless an amended clearance is obtained, an
emergency exists, or the deviation is in response to a traffic alert and
collision avoidance system resolution advisory. However, except in Class A
airspace, a pilot may cancel an IFR flight plan if the operation is being
conducted in VFR weather conditions. When a pilot is uncertain of an ATC
clearance, that pilot shall immediately request clarification from ATC.
(b) Except in an emergency, no person may operate an aircraft contrary
to an ATC instruction in an area in which air traffic control is
exercised.
(c) Each pilot in command who, in an emergency, or in response to a
traffic alert and collision avoidance system resolution advisory, deviates
from an ATC clearance or instruction shall notify ATC of that deviation as
soon as possible.
(d) Each pilot in command who (though not deviating from a rule of this
subpart) is given priority by ATC in an emergency, shall submit a detailed
report of that emergency within 48 hours to the manager of that ATC
facility, if requested by ATC.
(e) Unless otherwise authorized by ATC, no person operating an aircraft
may operate that aircraft according to any clearance or instruction that
has been issued to the pilot of another aircraft for radar air traffic
control purposes.
(Approved by the Office of Management and Budget under control
number 2120-0005)