IFR Fuel Requirements and Alternates
The requirements for IFR flight are contained in several FARs. I’ve pulled them together here with a summary at the end. Bolding is mine and I’ve mostly ignored helicopters. This post covers the pre-planning aspects: fuel, alternates, and filing a flight plan.
FAR § 91.167 Fuel requirements for flight in IFR conditions.
- (a) No person may operate a civil aircraft in IFR conditions unless it carries enough fuel (considering weather reports and forecasts and weather conditions) to—
- (1) Complete the flight to the first airport of intended landing;
- (2) Except as provided in paragraph (b) of this section, fly from that airport to the alternate airport; and
- (3) Fly after that for 45 minutes at normal cruising speed or, for helicopters, fly after that for 30 minutes at normal cruising speed.
- (b) Paragraph (a)(2) of this section does not apply if:
- (1) Part 97 of this chapter prescribes a standard instrument approach procedure to, or a special instrument approach procedure has been issued by the Administrator to the operator for, the first airport of intended landing; and
- (2) Appropriate weather reports or weather forecasts, or a combination of them, indicate the following:
- (i) For aircraft other than helicopters. For at least 1 hour before and for 1 hour after the estimated time of arrival, the ceiling will be at least 2,000 feet above the airport elevation and the visibility will be at least 3 statute miles.
- (ii) For helicopters. At the estimated time of arrival and for 1 hour after the estimated time of arrival, the ceiling will be at least 1,000 feet above the airport elevation, or at least 400 feet above the lowest applicable approach minima, whichever is higher, and the visibility will be at least 2 statute miles.
§ 91.169 IFR flight plan: Information required.
- (a) Information required. Unless otherwise authorized by ATC, each person filing an IFR flight plan must include in it the following information:
- (1) Information required under §91.153 (a) of this part;
- (2) Except as provided in paragraph (b) of this section, an alternate airport.
- (b) Paragraph (a)(2) of this section does not apply if :
- (1) Part 97 of this chapter prescribes a standard instrument approach procedure to, or a special instrument approach procedure has been issued by the Administrator to the operator for, the first airport of intended landing; and
- (2) Appropriate weather reports or weather forecasts, or a combination of them, indicate the following:
- (i) For aircraft other than helicopters. For at least 1 hour before and for 1 hour after the estimated time of arrival, the ceiling will be at least 2,000 feet above the airport elevation and the visibility will be at least 3 statute miles.
- (ii) For helicopters. At the estimated time of arrival and for 1 hour after the estimated time of arrival, the ceiling will be at least 1,000 feet above the airport elevation, or at least 400 feet above the lowest applicable approach minima, whichever is higher, and the visibility will be at least 2 statute miles.
- (c) IFR alternate airport weather minima. Unless otherwise authorized by the Administrator, no person may include an alternate airport in an IFR flight plan unless appropriate weather reports or weather forecasts, or a combination of them, indicate that, at the estimated time of arrival at the alternate airport, the ceiling and visibility at that airport will be at or above the following weather minima:
- (1) If an instrument approach procedure has been published in part 97 of this chapter, or a special instrument approach procedure has been issued by the Administrator to the operator, for that airport, the following minima:
- (i) For aircraft other than helicopters: The alternate airport minima specified in that procedure, or if none are specified the following standard approach minima:
- (A) For a precision approach procedure. Ceiling 600 feet and visibility 2 statute miles.
- (B) For a nonprecision approach procedure. Ceiling 800 feet and visibility 2 statute miles.
- (ii) For helicopters: Ceiling 200 feet above the minimum for the approach to be flown, and visibility at least 1 statute mile but never less than the minimum visibility for the approach to be flown, and
- (i) For aircraft other than helicopters: The alternate airport minima specified in that procedure, or if none are specified the following standard approach minima:
- (2) If no instrument approach procedure has been published in part 97 of this chapter and no special instrument approach procedure has been issued by the Administrator to the operator, for the alternate airport, the ceiling and visibility minima are those allowing descent from the MEA, approach, and landing under basic VFR.
- (1) If an instrument approach procedure has been published in part 97 of this chapter, or a special instrument approach procedure has been issued by the Administrator to the operator, for that airport, the following minima:
- (d) Cancellation. When a flight plan has been activated, the pilot in command, upon canceling or completing the flight under the flight plan, shall notify an FAA Flight Service Station or ATC facility.
FAR § 91.173 ATC clearance and flight plan required.
No person may operate an aircraft in controlled airspace under IFR unless that person has—
- (a) Filed an IFR flight plan; and
- (b) Received an appropriate ATC clearance.
Summary
For flight under Instrument Flight Rules (IFR)—whether or not Instrument Meterological Conditions (IMC) apply a flight plan must be filed and activated. Upon completion of the flight the pilot is responsible for closing the flight plan. Flights terminating at an airport with an functioning control tower are closed by the tower. Refer to the AIM 5−1−8. Flight Plan (FAA Form 7233−1)− Domestic IFR Flights for details.