Saturday, April 1, 2006
Despite constant warnings, controlled flight into terrain continues to vex general aviation pilots
So how can pilots avoid CFIT? An important step is to evaluate operational risks. As you can imagine, certain flight ventures are more precarious than others. The key is to properly prepare for flights that have an elevated hazard level while avoiding those that are downright dangerous. The Flight Safety Foundation has created a CFIT risk checklist outlining what operations increase risk and by how much (www.flightsafety.org/pdf/cfit_check.pdf). The majority of CFIT accidents occur during takeoff, climb-out, approach and landing.
Not surprisingly, flights with few visual cues, such as night operations and IMC flights, have a dramatically increased CFIT risk. Other situations that can increase the probability of the CFIT menace are “black hole” approaches or those at fields with limited lighting. Illuminations such as a visual approach slope indicator (VASI) can keep you safe (VASIs actually provide obstacle clearance within 4 nm and +/-10 degrees of the runway centerline).
For the instrument pilot, non-precision and circle-to-land arrivals carry more risk than precision and straight-in landings. Improperly using minimum descent altitudes (MDAs) and decision altitudes (DAs)—for example, descending below them when you’re not supposed to—is asking for trouble. Many unwanted collisions with trees and rocks have been attributed to pilots, knowingly or not, who have dismissed MDAs. Also, visual descent points (VDPs) and making “normal descents to land” are crucial to avoid seeing pines in the landing lights.
Some CFIT threats have nothing to do with being able to see the terrain. Lots of pilots don’t compare aircraft performance to what will be required for departure, en route and go-around. In a recent accident, a pilot simply smacked into a mountain because he neglected to compare his actual aircraft service ceiling (taking into account ambient air temperature because service ceiling is a function of density altitude) to the height of terrain en route. What a shame that a little planning could have prevented such a tragedy.
Many IFR departure procedures (DPs) exceed the performance capabilities of GA aircraft, yet pilots still head off without concern. And while the FARs don’t force Part 91 operators (most GA pilots) to comply with DPs and takeoff minima, to ignore them is nonsensical. Also, the thought that DPs should only be considered if you’re flying IFR is an ill-founded concept. There’s no better way to ensure obstacle avoidance from a strange airport at night than to use a DP.
Flying by yourself is another CFIT risk. This can be construed in two different ways. One way to fly on your own is to stay outside radar contact. No radar, no ATC low-altitude alerts. This is yet another great reason to take advantage of flight following, when available. The other type of solo flight is just as it sounds—you have an empty seat to your side. If you’re not in the plane by yourself, enlist the help of those on board. Even if your passengers aren’t aeronautically inclined, they can provide some assistance by helping you stay organized, etc. By adding an extra set of eyes to the cockpit, you can reduce risk (this is one reason why airliners have two pilots). One very important consideration: If you have more than one pilot in the cockpit, make sure at least one is actually flying the airplane. If that sounds stupid, it should, but several accidents, including one involving an L1011, have resulted from such situations.
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