February 2009 Issue

The First 400 Feet

Initiating a missed approach can be the busiest time you’ll ever spend in an airplane.

The standard missed approach is designed around a 200 ft/nm climb gradient. The minimum rate of climb you’ll need to maintain this gradient depends on groundspeed. For pilots of most IFR airplanes, these climb rates are easily achievable, but if your airplane is heavy, the density altitude is high, or you’re laboring with reduced engine power you may have to decide before ever beginning an approach near minimums if you’ll have the climb capability to miss the approach if needed. In fact, the minimums for many approaches, especially in hilly or mountainous terrain, are driven not by obstacle clearance requirements for the approach inbound to the airport, but the requirements for terrain or obstacle clearance for the missed approach. If there are towers or hills under the missed approach segment you may not be permitted to descend as low prior to the missed approach point as you would be allowed to otherwise. At the minimum 200 foot per nautical mile climb rate (below), you’ll be two miles from the point you initiate climb before you’re 400 feet above your lowest altitude. There’s a lot going on in the first two miles (the first 400 feet) when trying to climb out from a gray hole close to the unseen ground, so you need to properly manage this transition time to safely begin the missed.

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