MART Vol. II MO/MP - NESA - Civil Air Patrol

Density altitude’s effect on twin-engine aircraft can be catastrophic in theevent of a power loss by one engine. Most CAP-operated “twins” would not beable to climb at all and may not be able to maintain level flight under suchcircumstances. The pilot then flies an airspeed that allows a minimum rate ofdescent and starts looking for a suitable place to land. Hopefully, a runway will benearby.4.2.1 StrategiesThe mission staff can make a number of decisions to help minimize theeffects of high density altitude operations and thus maximize flight safety. Ifaircraft having turbo-charged or super-charged engines are available, the incidentcommander may assign their crews that part of the search over the high terrain.Supercharging or turbo charging regains some of the engine performance lostwith the decrease in air density, but cannot improve upon that lost from the wingsor propeller.Incident commanders may schedule flights to avoid searching areas of highelevation during the hottest times of the day. This is a tradeoff though, in that thebest sun angles for good visibility often coincide with the hot times of the day.The incident commander may also elect to limit crew size to minimize airplanetotal weight. Instead of dispatching a four-seat aircraft with a pilot, observer, andtwo scanners aboard, he may elect to send a pilot, observer and single scanneronly. Again, this represents a tradeoff, where some search capability is sacrificedfor a higher margin of safety.The pilot may decide to takeoff on a mission with only the fuel required forthat mission and the required reserve, rather than departing with full fuel tanks.Each crewmember can help by leaving all nonessential equipment or personalpossessions behind. In high density altitudes, airplane performance can beimproved significantly by simply leaving nonessential, excess weight behind.To help remember these conditions and their effects, an observer shouldremember the four "H's." Higher Humidity, Heat, or Height all result in reducedaircraft performance. Available engine power is reduced, climb capability isreduced, and takeoff and landing distances are increased.4.3 Effects on crewmember performanceThe factors previously discussed can have similarly degrading effects on theability of each crewmember to perform his or her job tasks. As air temperatureincreases, so does each crewmember's susceptibility to nausea, airsickness, anddehydration. As humidity increases with temperature, the body's ability toregulate its own temperature by perspiration can be negatively affected also,beginning the initial symptoms of heat exhaustion.When operating in high temperatures, crewmembers should make every effortto drink plenty of water, juice, or caffeine-free soft drinks prior to, during, and aftereach mission to help prevent dehydration. Even though an individual may not bephysically active, body water is continuously expired from the lungs and throughthe skin. This physiological phenomenon is called insensible perspiration orinsensible loss of water.The loss of water through the skin, lungs, and kidneys never ceases. Waterloss is increased in flight because of the relatively lowered humidity at altitude,63