Planning versus Flying

Were well familiar with the alternate planning requirements of the regulations on IFR flight, including the need for fuel. But we get flummoxed when we apply them to the flight.

Published: February 11, 2018 Updated: February 10, 2020

(Editor’s note: This is the first of a new article type we’ll run occasionally. We’re calling the article type, “Yes, You Can” or “No, You Can’t.” These articles will cover some commonly held misconceptions in the regs where you can do something you might have thought you couldn’t, or you can’t do something you thought you could. Please let us know what you think of this new article type, and if you have any suggestions for topics you’d like us to cover.)

You are planning an IFR flight. It’s a route you have flown many times before. You always file direct and most of the time the cooperative controllers give it to you. So you again file direct, toss in a nearby Class B or C as an alternate, and calculate your fuel requirements for a flight to the alternate. You’ve met your obligations under 14 CFR 91.167 and 91.169. Or have you?

We will review the basics. We’ll use airplanes to keep things simple (helicopters have a few more liberal requirements). The two pertinent regulations are 91.167 and 91.169, reproduced in part to the right.

Do I Need to File an Alternate?

Per 91.169(a) our IFR flight plan must include an alternate airport—we’ll call this the “filed alternate”—unless two conditions apply. A filed alternate is not required when the destination has a published instrument approach procedure (IAP) and the destination weather forecast for an hour before to an hour after our estimated time of arrival (ETA) is at least a 2000-foot ceiling with three statute miles visibility. Filing IFR to an airport without an IAP is fine, but you must have a filed alternate even if the weather is clear-and-a-million. The second condition is the familiar “1-2-3 Rule.”

Choosing the Alternate

Generally, to name an airport as a filed alternate, the minimum forecast at the ETA, the “standard alternate minimums,” is for two statute miles visibility with a 600-foot ceiling for a precision approach; an 800-foot ceiling for a nonprecision approach. The filed alternate does not have to have an IAP at all, but the conditions from the MEA to the ground must be VFR.

Not all airports qualify. Some can’t be used at all. When you see, the airport cannot be used as a filed alternate. Others just have the, which means the airport can be an alternate, but the required minimum forecast is not standard. Restrictions and limitations are described in the “IFR Alternate Airport Minimums” section of the FAA Terminal Procedures publication and on the Jeppesen airport diagram.

There are some nuances to choosing your filed alternate. Three stand out. First, a “precision approach” is an “ILS.” Period. A WAAS GPS LPV approach—with the same 200-foot decision height (DH) as its collocated ILS cousin—is anon-precisionapproach for the purpose of its use as a filed alternate. Second, if your panel GPS does not have WAAS,eitherthe destinationorthe filed alternate must have an available non-GPS approach. This restriction does not apply to GPS with WAAS-based systems. Compare AIM 1-1-17.b.5(c) with 1-1-18.c.9(a).

Third is the result of one of those questions to the FAA Chief Counsel that should probably have never been asked. Although an airport with no instrument approach whatsoever is an acceptable filed alternate if VFR from the MEA to the ground, according to a 2006 interpretation to Barry Lloyd, “Alternate NA” means the airport cannot be used as a filed alternate even in severe-clear weather.

It’s Only for Planning

These are primarily flightplanningrules; they’re not flightoperationrules. Some question why we even put them in the flight plan. Maybe it is just the FAA’s way of saying, “Hey you! This is really important!” Whatever the reason, the goal is to require adequate flight planning. The bigger point is, it does not restrict what we do once we are in the air.

We do not have to go to our filed alternate. Except perhaps in the case of lost communications or a lost flight, ATC doesn’t care or even know what we filed as an alternate. Subject to ATC clearance, of course, we can go anywhere, including those “Alternate-NA” airports. Once there, we may fly any approach to the minimums published on the approach chart. The best choice once we are underway may be different than when we filed our flight plan. Forecasts have been known to be wrong. A big airport may be a good ultimate “out,” but a closer nontowered field with an LPV approach, 200-foot (DA), cheap fuel, rental cars and a great on-airport restaurant might be more attractive.

Fuel Reserves

I saved the fuel reserve requirement for last because it is not as straightforward as the others. IFR is all about operating in a system in which your actions have immediate consequence for others. Going to a different airport than the filed alternate that ATC didn’t know of to begin with doesn’t cause any more of a system issue than any other type of diversion—a common event. But a “minimum fuel” advisory or “low fuel” emergency requiring priority handling can understandably have ATC pulling out its collective hair.

Let’s take a closer look at 91.167 that tells us we must have enough fuel to: “(1) Complete the flight to the first airport of intended landing; (2) Except [when the 1-2-3 Rule applies], fly from that airport to the alternate airport; and (3) Fly after that for 45 minutes at normal cruising speed [30 minutes for helicopters].”

Reading this, some claim you violate 91.167 if you land with less than 45 minutes fuel on board. Others insist it only describes the fuel required to be on board when you start the flight; you can forget about fuel reserves once in the air. Neither view paints a complete picture.

Landing with less than the reserve, does not automatically mean a violation. InFAA v. Eden(Order EA-4595 in 1997) a pilot faced certificate action for landing with less than a half hour of fuel. The NTSB dismissed the violation—the inquiry is not the amount of fuel the flight consumed, but the amount of fuel the flight was predicted to consume:

(Unfortunately, the dismissal was a pyrrhic victory for Mr. Eden. Other serious violations were upheld, and Eden’s pilot certificates and ratings were revoked.)

Pretty clear? Here is the flip side. Two years afterEden, an NTSB judge found a violation when a pilot ran out of fuel on the final leg of a round robin from Santa Monica to Camarillo, Santa Barbara, and back. The judge didn’t look at much more than the fact he ran out:

If that’s not enough, fuel exhaustion is also one of several situations in which one can comply with a regulation, but still be in violation of the 91.13 prohibition on “careless or reckless” operation (I always thought there was a literary irony to that regulation number.) The FAA’s position is summed up in the 2005 Gallagher Chief Counsel interpretation:

Key Points (Don’t be Like Eden)

A diversion and successful instrument approach at an airport other than the unseen filed alternate, or even the destination, raises no hackles. Fuel mismanagement often leads to a deeper inquiry. A 91.167 inquiry looks at adequate planning. “Adequate” planning takes “weather conditions and forecasts” into consideration; a summer afternoon with widespread thunderstorms forecast may require more fuel on board than a day of stratus. “Complete the flight” to the destination and the alternate requires planning for instrument approaches at both (a 2006 follow-up letter to Col. Gallagher).

As we have seen, a 91.13 “good judgment” inquiry goes beyond 91.167 and 91.169 requirements. Is filing “Direct” where full route clearances are the norm and then requesting priority for “minimum fuel” good judgment? Or the pilot who departs with reasonably adequate reserves but, despite substantial delays, presses on instead of making a fuel stop. Mr. Eden’sotherrevocation gives some answers, EA-3932 (1993).

Certificate actions for violating the regs usually arise from causing a problem, not from overzealous Safety Inspectors conducting a ramp check. Cause a problem in the system and you are likely to face an unpleasant inquiry. Don’t cause a problem. Check the regulatory boxes, but plan for reality and life should be good.

Mark Kolber is a pilot, CFII, and aviation lawyer whose views alternate almost as much as the weather.

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.

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.

(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.

(2) If no instrument approach procedure has been published in part 97 of this chapter … the ceiling and visibility minima are those allowing descent from the MEA, approach, and landing under basic VFR.

Planning versus Flying

Were well familiar with the alternate planning requirements of the regulations on IFR flight, including the need for fuel. But we get flummoxed when we apply them to the flight.

Do I Need to File an Alternate?

Choosing the Alternate

It’s Only for Planning

Fuel Reserves

Key Points (Don’t be Like Eden)

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Sorting Out NextGen

Do I Need to File an Alternate?

Choosing the Alternate

It’s Only for Planning

Fuel Reserves

Key Points (Don’t be Like Eden)

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