IFR Alternate Airports (1-2-3 Rule)

When filing an IFR flight plan, you must include an alternate destination airport when the weather forecast at your original destination predicts conditions below those specified in CFR 91.169. To help remember those conditions, you can use the 1-2-3 rule.

1 - During the time 1 hour before to 1 hour after the estimated arrival time
2 - Ceiling less than 2,000 feet
3 - Visibility less than 3 miles

If the above conditions exist, an alternate airport must be filed.

The alternate airport also has requirements that it must meet.

• If the airport has an instrument approach published, the weather must be forecast to be (at the ETA) better than the alternate airport minima specified in that approach or the following standard conditions:


• Precision Approach: 600ft ceiling and 2SM visibility


• Non-Precision Approach: 800ft ceiling and 2SM visibility

Instrument/Equipment for IFR Operations

Those required for VFR day and night flight plus:

G - Generator or alternator
R - Radios
A - Altimeter
B - Ball (slip/skid indicator)
C - Clock (seconds)
A - Attitude Indicator
R - Rate of turn (turn coordinator)
D - Directional Gyro

Instrument Checks

The five T’s are a quick instrument checklist that’s used when setting up for an instrument approach.

1. Turn
2. Time
3. Twist
4. Throttle
5. Talk

There's also the WIRE checklist for other quick reminders

W - Weather (ATIS/ASOS etc)
I - Instruments (VOR OBS set, DG aligned etc)
R - Radios (ILS/LOC/VOR/DME/ADF/COMM)
E - Everything else (Flaps, Gear, Engine power etc)