On September 4, 2013, about 0758 mountain daylight time, a Cessna T207 airplane, N211AS, sustained substantial damage during an off airport landing shortly after takeoff from runway 35L at the Colorado Springs Municipal Airport (COS), Colorado Springs, Colorado. The pilot reported that the airplane would not climb after takeoff and he executed a forced landing into a field. The pilot and passenger received minor injuries. The airplane sustained substantial damage to the wings and tail. The airplane was registered to and operated by Sanborn Map Company under the provisions of 14 Code of Federal Regulations Part 91 as an aerial observation flight. Visual meteorological conditions prevailed for the flight, which was operated on an instrument flight rules flight plan. The flight was originating at the time of the accident and was destined for the Lubbock Preston Smith International Airport (LBB), Lubbock, Texas.
The pilot reported that the engine start, taxi and pre-takeoff run-up were normal. He said that the performed the takeoff with the flaps up, boost pump off, cowl flaps open, gas on, and full rich mixture. On the takeoff roll, the throttle was advanced and engine instrument checked. He stated that the manifold pressure and propeller speed were at their maximum settings, and all other engine instruments were within normal operating parameters. The airplane accelerated and achieved liftoff about 65-70 mph. He stated that the airplane climbed a couple hundred feet and began to lower the nose to accelerate to normal climb speed (90-100 mph). He stated that he then noticed that the airplane stopped climbing and would not accelerate past 80 mph. He stated that while attempting to maintain altitude the airplane decelerated to 70 mph with the engine still at full power setting. With insufficient runway remaining to land, the pilot made a shallow right turn toward lower terrain and ultimately decided to make a landing in a field. The pilot reported that he was very surprised that with full power and in a descent that he was not able to keep the airspeed higher than 65-75 mph. During the off-airport landing the airplane landed hard and the pilot and passenger received minor injuries.
The reported weather at 0754 was: calm wind; 10 statute miles visibility; broken ceiling at 17,000 feet above ground level; temperature 21 degrees Celsius; dew point 12 degrees Celsius; altimeter setting 30.30 inches of mercury. Using the reported weather conditions, the density altitude was calculated to be about 8,000 feet above mean sea level. In the pilot's report, he listed the airplane's weight at the time of the accident as 3,790 pounds and the airplane's maximum gross weight as 3,800 pounds.
The airplane was a 1974 Cessna T207 airplane. It was powered by a turbo-normalized Continental TSIO-520-G engine rated to produce 300 horsepower. Using a Koch Chart, information provided by the pilot, the reported weather conditions, and takeoff performance information from the airplane manual, the takeoff ground run distance would have increased to about 2,640 feet, the distance to clear a 50 foot obstacle would have increased to about 4,728 feet, and the maximum rate of climb would have decreased to about 300 feet per minute. The takeoff performance was predicated on the use of 10 degrees of flap for takeoff.
The Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25A), in regard to airplane operation in the "region of reversed command", states:
"If during a soft-field takeoff and climb, for example, the pilot attempts to climb out of ground effect without first attaining normal climb pitch attitude and airspeed, the airplane may inadvertently enter the region of reversed command at a dangerously low altitude. Even with full power, the airplane may be incapable of climbing or even maintaining altitude. The pilot's only recourse in this situation is to lower the pitch attitude in order to increase airspeed, which will inevitably result in a loss of altitude."