Last month we discussed that the best way to deal with an engine fire is to quickly shut down the engine and deprive it of flammable fluids. Every aircraft, of course, has an engine-fire checklist, but not many pilots would take the time to locate and read it during such an emergency. The steps needed to cope with an engine fire should be committed to memory.
The next step requires landing "as soon as possible" or "immediately," depending on which checklist you happen to have. This advice applies even if the fire appears to have been extinguished. An airspeed change, for example, can allow a smoldering fire to rekindle with a vengeance. The goal is to land and evacuate with all possible haste.
An immediate landing obviously requires an expeditious descent. Unfortunately, the pilots of most aircraft are not offered any advice about the best way to get down in a hurry. Intuition tells us to simply chop the power and shove the nose down, but there can be more than that involved, especially when descending from a relatively high altitude in a complex airplane.
A rapid descent with fixed landing gear is a simple matter of closing the throttle, advancing the propeller-pitch control (if available) to low pitch (for maximum drag), and diving at the maximum-allowable speed.
A rapid descent in an aircraft with retractable gear is not quite so intuitive. Does the maximum sink rate occur at high speed with the wheels in the wells or at a lower speed with the gear extended?
Some helpful advice in this regard can be gleaned from the emergency procedures developed for those who fly pressurized aircraft. Checklists for these machines detail the steps required to make the most rapid descent possible in the event of a cabin pressure loss (decompression).
Such descent guidance also should be provided to pilots of nonpressurized aircraft but is not. A medical emergency or a fire at altitude can require an equally expeditious descent.
The recommended way to make an emergency descent in a pressurized Beechcraft Baron 58P is to push the propeller controls fully forward (flat pitch), close the throttles, establish an indicated airspeed of no more than 175 knots, lower the landing gear, and extend the flaps 15 degrees. The result is an almost 4,000-fpm descent.
The same maneuver in a Cessna 421C, however, is performed clean, with the gear and flaps retracted and the nose pushed over into a dive at the redline airspeed of 240 kt. (A descent in turbulence is made at 146 kt with gear and flaps extended.)
The difference in the two procedures reflects the difference in limiting airspeeds. The Baron has relatively high gear and (partial) flap extension speeds and can descend most expeditiously with the gear down and the flaps partially extended. The 421C, however, has lower limiting speeds; as a result, it cannot descend as rapidly when "dirty" at 146 kt as it can when "clean" at 240 kt.
There is a lesson here. When needing to make a rapid descent in an airplane for which a procedure has not been developed, dive clean if gear and flap speeds are relatively low, and dive dirty if gear and (partial) flap speeds are relatively high.
Pilots are discouraged from developing their own emergency-descent procedures. Prolonged diving at high speed and idle power is not healthy for engines, and diving at the redline should be regarded as an emergency procedure because of possible turbulence encounters during descent.
One of the most difficult aspects of an emergency descent with a fire is slowing in time to make a survivable landing.
Some years ago, a friend was flying his Beech A35 Bonanza from San Francisco to Santa Monica, California. During cruise, an engine fire developed as the result of a fuel leak. He headed for nearby Paso Robles Airport at high speed but made the mistake of passing over several emergency-landing sites. When the aircraft was on short final, horrified observers saw that an inferno had erupted under the cowling.
The aircraft shot across the runway threshold at extraordinary speed. The right-seat passenger opened the cabin door before touchdown in an effort to escape the flames and was killed in the process. The Bonanza was landed heavily on its nosewheel and began cartwheeling into a smoldering aluminum ball, claiming the lives of its pilot and rear-seat passengers.
Despite the urgent need to land and evacuate, a pilot must exercise discipline and take the time required to perform a survivable landing. With a fire urging haste, this is easier said than done.
Preventing an in-flight fire obviously is preferable to successfully coping with one and usually results from a methodical preflight inspection. Pilots should be on the alert for puddles, streaks, and stains of fuel, oil, and hydraulic fluid, both under and inside the cowling. Check the security and condition of fuel and oil lines. Also, be certain to tug gently on the ends of exhaust stacks to ensure that they are not cracked loose. Exhaust from a cracked stack is an ideal source of ignition for an engine fire.
Never trust in luck and the statistical infrequency of an engine fire to insulate you from such an emergency. A sudden gush of flame can be harsh notice that your luck has run out.
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