WPR20LA024

On November 17, 2019, about 1552 mountain standard time, a Piper PA28R-180, N3206R, was substantially damaged when it was involved in an accident near Ogden, Utah. The flight instructor and pilot receiving instruction were seriously injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 instructional flight. Neither the flight instructor nor the pilot receiving instruction had a clear recollection of the events leading to the accident but recalled they were practicing touch-and-go landings when the accident occurred. No witnesses came forward; however, a video recorded from a vehicle on a nearby freeway, captured the airplane as it struck the top of a 40-ft-tall billboard and descended to the ground about 2,200 ft southwest from the departure end of runway 17 and adjacent to the freeway. All major components of the airplane were in the small debris field around the wreckage. The wings and fuselage were substantially damaged. The airplane was equipped with a backup landing gear extender system. The system is designed to automatically extend the landing gear even if the position selector is up, depending on airspeed and engine power. The system will also prevent the landing gear from retracting until the airplane has accelerated to approximately 85 mph with full power, regardless of the landing gear selector switch position. Manual override of the system is possibly by using an emergency gear lever located between the front seats to the left of the flap handle (see figure). Postaccident examination of the wreckage revealed the landing gear was extended, the landing gear selector switch was in the up position, the emergency gear lever was near the normal (non-override) position, and the flaps were in the 25°, second notch position. The flap torque tube position, along with the chain length over the torque tube sprocket were also consistent with flaps set to 25°. Flight control continuity was established for the aileron, rudder, and elevators, from the cockpit controls to the respective control surfaces. There were no mechanical malfunctions or failures with the airframe or engine that would have precluded normal operation. The operation of the backup gear extender system is detailed in the airplane owner’s handbook; however, when questioned about his knowledge of the system, the flight instructor replied that he did not study the airplane’s systems very much. Figure. Photo of the emergency gear lever on the accident airplane. According to a mechanic employed by the operator, the backup gear extender system tested and operated normally when it was inspected during the annual inspection on January 7, 2018. Density altitude was calculated to be 4,472 ft. Runway 17 was an asphalt runway that measured 5,197 ft by 100 ft. The calculated weight of the airplane at takeoff was about 2,197.5 pounds. According to the operator’s handbook, takeoffs are normally made with the flaps up. However, the handbook stated for short fieldtakeoffs, or takeoffs under difficult conditions, such as deep grass or soft surface, distances can be reduced appreciably by setting the flaps to 25°. The airplane owner’s handbook stated that with the airplane at maximum gross weight of 2,500 pounds, the required takeoff distance would be 2,000 ft with flaps at 0°, and 1,700 ft with flaps at 25°. The distance to clear a 50 ft obstacle with flaps at 25° was 3,200 feet, and about 3,800 ft to clear a 50 ft obstacle with flaps at 0° ft. The calculated rate of climb at the observed environmental conditions would have been about 650 ft per minute with the flaps and landing gear retracted. The owner’s handbook did not contain a chart to calculate the climb rate with the landing gear extended. The calculated backup gear extender system retraction speed for 4,000 ft was about 92 mph indicated airspeed (IAS). Postaccident interviews with the flight instructor and the pilot receiving instruction were conducted but neither were confident in the accuracy of their memories of the accident. In an email sent shortly after the accident while he was still under the effects of medication, the flight instructor conjectured that he was not sure that this is what happened on the flight, but if he was flying toward a billboard without power to climb and he couldn’t go around or under it, he could see himself trying to use full flaps in a desperate attempt to rise the airplane over the obstacle. He also conjectured that they would not have been performing a soft-field takeoff, and if he were halfway down the runway, and it was safe, but because of density altitude, he probably would have added 10° flaps to aid the airplane’s climb. The flight instructor and the pilot receiving instruction were able to give details of preaccident events including their first flight in the airplane, which occurred 4 days before the accident. During the preflight, the pilot receiving instruction recalled that he had asked why the airplane appeared to have two pitot-static tubes, one underneath the left wing, and one above the left wing, which the flight instructor could not explain. The pilot receiving instruction later discovered on his own that the apparent second pitot-tube was the mast for static and high-pressure air source for the backup gear extender system. According to the flight instructor, on the flight prior to the accident, the gear in transition light did not extinguish and the airplane felt sluggish. He stated that he cycled the landing gear and got better performance but the gear in transition light remained illuminated for the rest of the flight. According to the pilot receiving instruction, on the flight prior to the accident, the flight instructor was demonstrating a touch and go maneuver, and after the takeoff, the landing gear would not retract. He recalled that the gear came up eventually, after the flight instructor lowered the nose slightly to gain airspeed. Prior to instructing in the airplane, the flightinstructor accrued about 5 hours of experience in the airplane. Two fellow flight instructors, employed by the accident operator, each flew one training flight with the accident flight instructor, in the accident airplane. One fellow instructor reported that the flight was uneventful with no problems with the landing gear. He stated that on the flight, there was not much discussion about the airplane’s systems, but he did mention to the accident pilot that if the gear didn’t come up, use the [emergency gear up] lever. The second fellow instructor flew with the accident flight instructor on his second flight in the airplane. He stated that the flight was fine, and they had no problems with the airplane. He recalled that he did discuss the backup gear extender system with the accident flight instructor but did not recall what they specifically talked about. The airplane owner’s handbook states in part: After takeoff, the pilot should retract the landing gear with the gear selector switch located on the instrument panel. If the airplane is equipped with the backup gear extender and the gear selector switch is placed in the gear up position before reaching the airspeed* at which the system no longer commands the gear down, the gear will not retract. This simply indicates that the system is functioning. Normally the airplane should be allowed to accelerate to this airspeed* before placing the selector switch in the gear up position. For obstacle clearance on takeoff and for takeoff from high altitude airports, on aircraft equipped with the backup gear extender, the landing gear can be retracted at the pilot’s discretion by placing the gear selector switch in the up position and then holding the emergency gear lever in the override position. It is necessary to hold the lever in the override position until the airspeed* required for retraction by the system has been attained. * Approximate airspeed of 85 mph IAS at sea level to 100 mph IAS at 10,000 ft, with straight line variation between. In March 1988, Piper Aircraft issued Service Bulletin (SB) 866A, which superseded SB 866 and indicated mandatory compliance. SB866A reiterated the required removal of the backup gear extender due to a concern that pilots, not familiar with all aspect of the system’s operation, might inadvertently encounter situations that would adversely affect safe flight. The SB provided an alternative means of compliance for affected owner/operators who chose to continue operation of their aircraft with the backup gear extender system installed and functioning. A component of SB 866A advised that pilots do the following: Review and understand all information contained in the applicable Airplane Flight Manual/Pilot’s Operating Handbook, Operations, Limitations and Systems section, pertaining to the normal and emergency operation of the Back Up Landing Gear Extender System for the affected aircraft model. SB 866A stated, in part: Failure to comply with this Service Bulletin couldresult in an inability to attain/maintain safe airspeeds including, but not limited to reduced rate of climb due to delayed landing gear retraction.