Asymmetric Thrust and Rudder Authority on a Piston Twin

The published single-engine climb rate of 220 ft per minute is at sea level and presumably at maximum take-off mass. At 4000 ft density altitude, the engine power and propeller thrust are reduced, and the climb rate falls roughly in proportion to the density ratio. The density ratio at 4000 ft is about 0.89, so the climb rate might be around 195 ft per minute before mass correction. At 95% of maximum take-off mass, the climb rate improves by roughly 5 to 10%, so the net climb rate is perhaps 200 to 210 ft per minute. That is a positive but modest climb gradient. The single-engine service ceiling of 6500 ft means the aircraft can climb, but slowly, and the margin above the terrain is the critical factor. The pilot should not expect a rapid climb and should plan a shallow climb to a safe altitude rather than an aggressive one. The judgement is that the aircraft can climb, but the crew must manage speed and configuration carefully.

With the left engine failed and feathered, the operating right engine produces thrust that yaws the aircraft to the left. The pilot counters with right rudder. The required rudder force is high but within capability, which means the aircraft is controllable. Reducing power on the operating engine would reduce the yaw but also reduce climb performance, so it should not be done unless control is lost. The correct technique is to maintain VY, use rudder to hold heading, and use a small amount of bank toward the operating engine to help control the yaw. The counter-rotating propellers reduce the critical-engine effects, but the failure of the left engine still produces a yaw toward the left. The pilot should not reduce power because the aircraft is climbing and the control margin is adequate. If the rudder force became excessive or the aircraft could not hold heading, reducing power would be appropriate, but that is not the case here. The judgement is to maintain power and control.

The aircraft is at 400 ft above ground level with a positive single-engine climb rate of about 200 ft per minute. The departure airport has a 1200 m runway, which is adequate for a single-engine landing if needed, but the aircraft is already airborne and climbing. The single-engine service ceiling of 6500 ft is above the current altitude, so the aircraft can continue to climb. The decision should be to continue the climb to a safe altitude, clean up the aircraft, and then assess the situation. Returning immediately would require a descent and a landing, which is not necessary if the aircraft is climbing and controllable. The pilot should notify ATC, declare an emergency if appropriate, and plan a diversion to an airport with better emergency services if one is available. The key judgement is that a positive climb rate at 400 ft is sufficient to continue, but the pilot must monitor the climb rate and be prepared to level off if it deteriorates. The final decision is to continue the climb and then divert.