AFH 4-15

1. A pilot of a normally-aspirated, twin-engine airplane departs out of Rocky Mountain Metropolitan airport (KBJC) in the morning on a nice summer day and flies into Aspen/Pitkin County airport (KASE). 2. The pilot enjoys the scenery around Aspen, eats lunch, and decides to return home in the early hot afternoon. 3. The pilot departs KASE off of runway 33. At full throttle/power the airplane takes longer to accelerate but rotates at the normal speed. 4. The pilot pitches to the normal pitch target, retracts the gear, and initiates a climb. 5. The pilot notices the airplane isn’t performing as desired. The pilot checks to see if the gear is up and adjusts the mixtures to try and get a little more power. 6. The terrain is rising, the pilot gradually pitches up, and the airplane starts losing airspeed. 7. The airplane quits climbing. 8. The stall horn begins to sound. The above scenario is hypothetical, but there have been very similar situations that have ended tragically. The airplane in the above scenario has encountered an unintended deceleration and impending sink rate that could rapidly become irreversible. This can be shown in two ways, using the traditional power curve [Figure 4-14] and the energy map [Figure 4-15]: Figure 4-14. The energy depletion scenario viewed in the power required and available curve. Compared with the power available curve depicted in Figure 4-4, note the lower power available curve at this high elevation (7,820 feet at the departure airport) and higher density altitude than standard during a hot afternoon.