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IFR Fix: Alternate realities

There’s a new endorsement in your logbook for successfully completing an instrument proficiency check. There’s a destination, a motivation, and a forecast of instrument meteorological conditions for the flight.

Now if you can winnow out other red flags that winter IFR raises, the trip may offer an opportunity to put that hard-earned IPC to immediate use.

The approach of winter’s latest low has put IMC in the forecast, but if you can stay on schedule, you won’t penetrate the frontal zone, with its moderate turbulence and potential wind shear.

It will be a very cold day, but that reduces the likelihood of icing in cloud layers.

Here’s a glitchy item from your preflight weather data: Your estimated time of arrival falls in the middle of a three-hour period when the destination forecast is “04008KT 2SM -SN OVC020.”

Not bad for an approach. But with the terminal forecast lower than “two thousand and three” (2,000-foot ceiling and three miles visibility), you must designate an alternate airport.

Don’t just pick the nearest airport that conforms to 14 CFR 91.169 requirements for alternate airport weather minimums and move on to the next step of your planning. You should carefully subject the proposed flight to a new set of risk-analysis variables.

How would you navigate to the alternate after missing the approach at your destination? Vectors direct would be lovely, but there’s no guarantee. So review likely routing scenarios (and possibly, holding for your clearance) and give the transition phase a generous fuel allowance.

If an approach didn’t get you in at your destination, weather may be chaotic at the alternate. Best bet would be an airport with a precision approach, where a minimum 600-foot ceiling and two miles visibility must exist based on “appropriate weather reports or weather forecasts, or a combination of them.”

Now suppose your desired alternate is Connecticut’s Groton-New London Airport: Note that alternate minimums apply for the ILS or LOC Rwy 5 approach: “ILS, Categories B, C, D, 700-2.”

Whenever an alternate airport is in play, include it in your in-flight weather checks. If it is going down, find something better before it’s needed.

For a pilot who flies IFR infrequently enough to need an IPC, weather requiring an alternate should raise a caution flag about the go/no-go decision, challenging you to find that perennial balance point between what’s legal, and what’s both legal and safe.

Dan Namowitz
Dan Namowitz
Dan Namowitz has been writing for AOPA in a variety of capacities since 1991. He has been a flight instructor since 1990 and is a 35-year AOPA member.
Topics: IFR, IFR, Technique

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