The Nearest Alternate Nobody Files - How to Build a Real Fuel and Weather Plan Around 91.169 for Your Night Cross-Country

An alternate airport is only useful if it’s forecasting better weather than your destination and you’re carrying enough fuel to reach it comfortably. 14 CFR 91.169 tells IFR pilots when an alternate is required and what weather it must meet, while 91.167 sets the fuel you must carry to get there. The smartest move - whether you fly IFR or VFR - is to skip the nearest legal alternate and choose the best usable one, then plan the gas around it.

When Do You Have to File an Alternate? (The 1-2-3 Rule)

Under 91.169, an IFR flight generally requires a filed alternate. The well-known exception pilots call the 1-2-3 rule lets you skip it: if the forecast at your destination, from one hour before to one hour after your estimated time of arrival, shows a ceiling of at least 2,000 feet and visibility of at least 3 statute miles, no alternate is required.

Miss any part of that window and you must file. One hour each side, a 2,000-foot ceiling, 3 miles of visibility. It’s easy to remember and easy to forget at ten o’clock at night when the destination looks good enough.

VFR pilots flying at night are not legally required to file an alternate. But planning one anyway is the single biggest free safety upgrade you can make - more on that below.

What Weather Does the Alternate Itself Need?

Filing an alternate is not the same as filing a good alternate. The airport you name has to meet its own minimums at the time you’d arrive there, and those minimums are deliberately higher than your destination’s.

If the alternate has a published instrument approach, the standard requirement is:

• 600-foot ceiling and 2 miles visibility for a precision approach
• 800-foot ceiling and 2 miles visibility for a non-precision approach

If the airport has no instrument approach at all, the forecast must let you descend from the minimum en route altitude, complete the approach, and land under basic VFR.

Think about what that means. Your destination can be legal on a 2,000-foot ceiling, but your alternate must forecast better than that. The alternate is your plan for when the destination goes down, so it has to be the place with more margin, not less.

Why the Fuel Rule and the Alternate Rule Are Married

For IFR, 91.167 requires enough fuel to fly to your destination, then to your alternate, and then for 45 minutes beyond that at normal cruise speed. Destination, then alternate, then 45 minutes. That’s the legal floor, and you want to fly above the floor.

Here’s the trap. Pilots picking an alternate to satisfy the paperwork tend to grab the closest legal airport, because a nearer alternate means less required fuel - which means less gas or more bags. On paper that’s fine. But the closest legal field at eleven at night might be unfamiliar, short, unlit, unstaffed, with a weather trend heading the same direction your destination just went.

So don’t pick the nearest legal alternate. Pick the best usable alternate, and carry the fuel to reach it comfortably.

How Do I Pick a Genuinely Usable Alternate?

Run every candidate through five checks:

1. Weather trend, not just a snapshot. Read the Terminal Aerodrome Forecast and ask which way it’s moving. An improving alternate beats one that’s technically legal but sliding downhill.
2. Is it upwind or “upweather” of the trouble? If a front is moving west to east and swallowing your destination, an alternate to the east gets eaten next. Put your alternate behind the weather.
3. Does it have an approach you’re current and comfortable with? Ideally more than one, so a single out-of-service navaid doesn’t strand you.
4. Services, especially at night. Fuel available, a lit runway, and a way to get a rental car or hotel if you’re staying. There’s no shame in staying - the saddest accident reports involve a tired pilot who pressed on instead of landing somewhere safe and boring.
5. Distance your fuel can actually cover with margin, not just the legal 45 minutes.

What Should VFR Pilots Do on a Night Cross-Country?

Night VFR into deteriorating weather is one of the oldest killers in general aviation, and it usually starts with a pilot who had exactly one plan. The law doesn’t require you to file an alternate, but the sky doesn’t care what the law requires.

Before you launch, pick two airports along your route you’d divert to if the destination weather went sour. Write down their frequencies, runway lengths, field elevations, and whether they’ll have fuel and lights when you arrive. You don’t file them - you just know them. You’ve turned a one-plan flight into a three-plan flight.

Then, as you fly, keep a running answer to one question: if the engine kept running but the weather quit, where would I go right now? The answer should change as you move down the route, and it should always be a real place you can reach on the fuel in your tanks. Answer that at any moment and you’re flying like a professional, rating or not.

How Do I Explain My Alternate on a Checkride?

Examiners want more than a legal alternate scribbled in a box - they want to see why you chose it. Expect the question, “Why this airport?” A strong answer sounds like this:

“Because it’s behind the weather, it has two approaches I’m current on, the forecast is steady or improving through my arrival window, it has fuel and a courtesy car, and I’m carrying enough gas to reach it with better than an hour to spare.”

That answer shows you don’t just know the rule - you know the reason behind it.

Key Takeaways

• Under 91.169, IFR flights need an alternate unless the 1-2-3 rule is met: a 2,000-foot ceiling and 3 miles visibility from one hour before to one hour after ETA.
• Alternate minimums are higher than destination minimums: 600-2 for precision, 800-2 for non-precision, and basic-VFR capability where there’s no approach.
• 91.167 requires fuel to reach your destination, then your alternate, then fly 45 more minutes - treat that as a floor, not a target.
• Choose the best usable alternate (behind the weather, good trend, familiar approaches, night services), not the nearest legal one.
• VFR pilots should plan two divert fields every night flight even though the law doesn’t require it.