ERA13LA281 · Cessna 172K

After an uneventful instructional flight, the student pilot entered the left downwind leg of the traffic pattern while the airplane was at 1,200 ft mean sea level. The flight instructor then asked the student to turn onto the base leg of the traffic pattern, but "he was slow to respond," and the airplane was too fast, which extended the downwind leg farther out than normal. The flight instructor then noticed that the student had not extended the wing flaps to the 10-degree position. The student pilot then extended the wing flaps to 10 degrees and started to slow the airplane. The flight instructor then asked the student to turn onto final, and, because of the extended downwind leg, to stop descending and add power. The student then arrested the descent, but he failed to add power as instructed. The flight instructor again asked the student to add power; however, the student did not respond by either adding power or by asking the flight instructor for clarification. The flight instructor stated that he was distracted by the airplane's airspeed and altitude and the student's lack of response and that he did not see the power lines during the final approach even though he had flown over them many times. When he finally did see the power lines, he took control of the airplane and then added full power and maximum up elevator. However, the airplane struck a static wire that ran along the top of the power poles, nosed over, and impacted terrain.

Review of Federal Aviation Administration records revealed that the student pilot held a third-class medical certificate with the limitation that he "must use hearing amplification." However, the student pilot was not wearing a hearing aid during the accident flight; therefore, he might not have heard the flight instructor's command to increase engine power, which would explain his failure to do so as instructed. Further, neither the student pilot nor the flight instructor were wearing headsets in the loud cockpit of the single-engine airplane, which also could have made it difficult for the student pilot to hear the flight instructor's command.

Although the power lines were not included in the airport information in the Airport/Facility Directory, they were depicted in the sectional aeronautical chart for the area. Examination of the power lines revealed that not only were they below the runway's 7.00-degree glidepath that was provided by a pulsating visual approach slope indicator to ensure obstacle clearance but that they were also below the obstruction identification surfaces listed in federal regulations, and, in many areas, they were at or below the trees located on the approach end of the runway. Given this information and the fact that the flight instructor had flown over them many times, the power lines should not have been a hazard. The flight instructor's slow response to the student pilot's failure to increase power during the descent led to the airplane's collision with the wire.

Verbatim NTSB analysis and probable cause from the NTSB dataset