IFR flight plan and alternate airport requirements14 CFR 91.169 IFR flight plan: Information required
An IFR flight plan must include an alternate airport unless the first airport of intended landing has a published instrument approach and, for at least 1 hour before and for 1 hour after the ETA, the weather is forecast to be at least a 2,000-foot ceiling and 3 statute miles visibility. An airport can be listed as the alternate only if its forecast at your ETA there meets the alternate minimums in paragraph (c).
By the ATIS Alerts team · Updated October 15, 2026 · Regulation text current as of October 14, 2026. A study aid based on the official regulation text, not legal advice or an FAA interpretation.
At a glance
- Unless ATC authorizes otherwise, the flight plan must include the information required by 91.153(a) and, unless paragraph (b) applies, an alternate airport (a).
- No alternate is required when the first airport of intended landing has a Part 97 standard instrument approach (or a special procedure issued to the operator) and, for aircraft other than helicopters, for at least 1 hour before and for 1 hour after the ETA the ceiling is forecast at least 2,000 feet above airport elevation and the visibility at least 3 statute miles (b).
- An airport qualifies as an alternate only if the forecast at the ETA there meets the alternate minima (c).
- With a published approach, airplanes use the alternate minima specified in the procedure, or if none are specified: precision approach, ceiling 600 feet and visibility 2 statute miles; nonprecision approach, ceiling 800 feet and visibility 2 statute miles (c)(1)(i).
- With no instrument approach, the ceiling and visibility must allow descent from the MEA, approach and landing under basic VFR (c)(2).
- After a flight plan is activated, the pilot in command must notify an FAA Flight Service Station or ATC facility when canceling or completing the flight (d).
In plain English
Section 91.169 answers two questions every instrument student practices: when does an IFR flight plan need an alternate airport, and which airports can be that alternate. Paragraph (a) requires the flight plan to include the information listed in 91.153(a) and, except as provided in paragraph (b), an alternate airport. Both requirements apply unless ATC authorizes otherwise.
Paragraph (b) is the rule pilots shorten to 1-2-3. No alternate is required when Part 97 prescribes a standard instrument approach procedure for the first airport of intended landing (or the operator has been issued a special instrument approach procedure for it) and appropriate weather reports or forecasts indicate that, 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 at least 3 statute miles. Helicopters use a different test in (b)(2)(ii): at the ETA and for 1 hour after, a ceiling of at least 1,000 feet above airport elevation or at least 400 feet above the lowest applicable approach minima, whichever is higher, and at least 2 statute miles visibility.
Paragraph (c) sets the bar for the alternate itself, measured at the estimated time of arrival at the alternate airport. If the airport has a published instrument approach, airplanes use the alternate minima specified in that procedure. When the procedure specifies none, the rule's standard minima apply: a 600-foot ceiling and 2 statute miles visibility for a precision approach, or an 800-foot ceiling and 2 statute miles visibility for a nonprecision approach. Helicopters need a ceiling 200 feet above the minimum for the approach to be flown and at least 1 statute mile visibility, never less than the minimum visibility for that approach.
An airport with no instrument approach can still be listed as an alternate under (c)(2), but only if the forecast ceiling and visibility allow descent from the MEA, approach and landing under basic VFR. Paragraph (d) closes the loop: once a flight plan has been activated, the pilot in command must notify an FAA Flight Service Station or ATC facility when canceling or completing the flight.
Common mistakes
- Checking the destination forecast only at the ETA. The (b) test covers at least 1 hour before and 1 hour after the estimated time of arrival.
- Using the 1-2-3 numbers for the alternate. Paragraph (b) decides whether you need an alternate; paragraph (c) sets the separate minimums the alternate must meet at your ETA there.
- Using the 600-2 and 800-2 standard minimums when the approach procedure specifies its own alternate minima. The standard numbers in (c)(1)(i) apply only if none are specified.
- Assuming an airport without an instrument approach can never be an alternate. Under (c)(2) it can, if the forecast allows descent from the MEA, approach and landing under basic VFR.
The official text
14 CFR 91.169 as published on the eCFR, current as of October 14, 2026.
(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
(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.
(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.
Test yourself
Practice questions from our free FAA written test prep that cite 14 CFR 91.169.
Instrument Rating
An alternate airport must be filed when, from 1 hour before to 1 hour after the ETA, the destination forecast is below:
- A. a 2,000-foot ceiling and 3 statute miles visibility.
- B. a 1,000-foot ceiling and 3 statute miles.
- C. a 3,000-foot ceiling and 5 statute miles.
- D. a 500-foot ceiling and 1 statute mile.
Show answer
A. a 2,000-foot ceiling and 3 statute miles visibility. The '1-2-3 rule' (91.169): if within 1 hour before to 1 hour after ETA the forecast ceiling is at least 2,000 ft and visibility at least 3 SM, no alternate is required. Below either value, you must file an alternate.
More Instrument Rating practice →CFII Airplane
The 1-2-3 rule for filing an alternate requires an alternate unless, from 1 hour before to 1 hour after the ETA, the forecast is at least:
- A. a 2,000-foot ceiling and 3 statute miles visibility.
- B. a 1,000-foot ceiling and 3 statute miles visibility.
- C. a 3,000-foot ceiling and 2 statute miles visibility.
- D. a 2,000-foot ceiling and 2 statute miles visibility.
Show answer
A. a 2,000-foot ceiling and 3 statute miles visibility. ±1 hour, 2,000 feet, 3 miles. An alternate is ALWAYS required if the destination has no published instrument approach, a case students often miss because the 1-2-3 rule feels like the whole answer.
More CFII Airplane practice →Instrument Helicopter
A helicopter IFR flight plan need not list an alternate airport when the destination forecast, from the ETA through 1 hour after, shows:
- A. a ceiling at least 1,000 feet above the airport elevation or 400 feet above the lowest applicable approach minima, whichever is higher, and visibility at least 2 SM.
- B. a ceiling of at least 2,000 feet and visibility of at least 3 SM from 1 hour before to 1 hour after the ETA.
- C. a ceiling of at least 600 feet and visibility of at least 2 SM at the ETA.
- D. basic VFR conditions at the ETA.
Show answer
A. a ceiling at least 1,000 feet above the airport elevation or 400 feet above the lowest applicable approach minima, whichever is higher, and visibility at least 2 SM. The helicopter test replaces the airplane 1-2-3 rule: the window runs from ETA to ETA plus 1 hour (not plus-or-minus), and the ceiling test is 1,000 above the airport or 400 above the lowest minima, whichever is higher, with 2 SM. The 2,000-foot, 3 SM, plus-or-minus-1-hour choice is the airplane rule: the intended trap.
More Instrument Helicopter practice →CFII Helicopter
For a helicopter, the alternate airport weather minimums at the ETA are:
- A. a ceiling at least 200 feet above the minimum for the approach to be flown, and visibility at least 1 SM but never less than that approach's minimum visibility.
- B. 600-2 for a precision approach and 800-2 for a nonprecision approach.
- C. 1,000-3 at all alternates.
- D. the published landing minimums for the approach to be flown.
Show answer
A. a ceiling at least 200 feet above the minimum for the approach to be flown, and visibility at least 1 SM but never less than that approach's minimum visibility. Helicopters have their own alternate minima: 200 feet above the approach minimum, and 1 SM or the approach's minimum visibility, whichever is higher. The 600-2 and 800-2 defaults most students memorize are the airplane rule.
More CFII Helicopter practice →
Questions pilots ask
When is an alternate airport required on an IFR flight plan?
Unless ATC authorizes otherwise, an alternate is required unless the first airport of intended landing has a Part 97 standard instrument approach procedure (or a special one issued to the operator) and weather reports or forecasts indicate, for at least 1 hour before and for 1 hour after the ETA, a ceiling of at least 2,000 feet above the airport elevation and visibility of at least 3 statute miles (91.169(a)(2) and (b)). Helicopters use the test in (b)(2)(ii).
What are the standard alternate minimums?
If the approach procedure at the alternate specifies no alternate minima, airplanes use a ceiling of 600 feet and visibility of 2 statute miles for a precision approach, or a ceiling of 800 feet and visibility of 2 statute miles for a nonprecision approach, forecast at the ETA at the alternate (91.169(c)(1)(i)).
Can an airport without an instrument approach be my alternate?
Yes, if the forecast at your ETA there shows a ceiling and visibility that allow descent from the MEA, approach and landing under basic VFR (91.169(c)(2)).
What is the 1-2-3 rule for IFR alternates?
It is shorthand for 91.169(b)(2)(i): for at least 1 hour before and for 1 hour after the ETA, a ceiling of at least 2,000 feet above the airport elevation and visibility of at least 3 statute miles at the first airport of intended landing. When that forecast holds and the airport has a Part 97 standard instrument approach (or a special one issued to the operator), no alternate is required (b)(1). The same test removes the alternate fuel requirement in 91.167(b).