Climb and Maintain ...

The flying adventures of a software engineer in the Pacific Northwest.

Saturday, July 14, 2007

Hot and High

My recent trip took place during a heatwave throughout most of the Southwestern United States. The Reno airport, with an elevation of 4,400 feet, registered +45 degrees C at the time I landed. That equated to a density altitude of about 8,600 feet. While the runways at Reno are long enough to alleviate any density altitude issues associated with takeoff and landing (other than, of course, the airplane accelerating more slowly and taking up much more runway), consideration has to be given to climb performance after takeoff -- especially if one is piloting an aircraft under IFR.

Reno, as a major airport, is served by a number of standard instrument departure procedures. Controllers usually do not realize (or maybe do not care) that an aircraft may not be able to fly a certain departure procedure because of the required climb rates. For example, take a look at the Mustang Seven Departure. This departure requires a minimum climb gradient of 525 feet per nautical mile to 8000 feet, which at 75 knots ground speed translates to about 650 feet per minute. This is no small feat for a Cessna 182 -- even a lightly loaded one -- when the temperature on the ground is +45 degrees C (and even when the temperature is standard, a Cessna 182 might not be able to climb that fast).

What's the solution? Refuse a clearance that includes a standard instrument departure (SID). Or, if you are already on a SID, and are unable to meet the required climb gradient, say so, and request a VFR climb to altitude while providing your own terrain separation. This may mean flying the route provided by the SID -- but at a lower climb rate -- or flying a different route altogether. Either way, the controllers will be glad you told them about your predicament. :-)

0 Comments:

Post a Comment

<< Home