Definition
The Federal Aviation Regulation that prescribes the procedures a pilot must follow when two-way radio communication is lost while operating under Instrument Flight Rules (IFR). It specifies what route to fly, what altitude to maintain, and when to begin descent for approach, depending on whether the aircraft is in visual meteorological conditions (VMC) or instrument meteorological conditions (IMC) at the time of the failure.
Plain English
The rule that tells an IFR pilot exactly what to do if the radios stop working: where to fly, how high, and when to start the approach.
Context Anchor
Seen in instrument training, lost-communication procedures, IFR clearance discussions, and FAA handbook sections on communication failure.
Derivation
14 CFR means Title 14 of the Code of Federal Regulations -- the section of U.S. federal law covering aeronautics and space. Part 91 contains the general operating and flight rules for all civil aircraft. The number after the decimal (.185) identifies the specific section within Part 91. So '91.185' is shorthand for 'Part 91, Section 185.'
Why Pilots Care
Knowing this section allows a pilot to continue an IFR flight safely and legally after losing radio contact, following prescribed routes, altitudes, and approach procedures.
Grounding Statement
If the radios fail while you are flying in the clouds on an IFR clearance, this rule is the standard plan for continuing the flight without new instructions from air traffic control.
Intuition Check
Do not read 91.185 as a frequency, checklist item, or procedure name. It is a regulation citation: the legal rule that describes the lost-communication procedure for IFR flight.
Example Sentence 1
After losing communication with Center in IMC, the pilot continued the flight in accordance with 91.185, holding the last assigned altitude and route to the destination.
Example Sentence 2
Under 14 CFR Part 91.185, the aircraft proceeded to the destination and executed the published approach.