N78NR

HISTORY OF FLIGHT

On January 31, 2015, about 1305 Alaska standard time, a wheel/ski-equipped Piper PA-18 airplane, N82735, and a ski-equipped Piper PA-18 airplane, N78NR, collided midair near South Hollywood Airport, about 5 miles southwest of Wasilla, Alaska. N82735 was operated by the State of Alaska Department of Public Safety, Alaska State Troopers, Anchorage, Alaska as a visual flight rules (VFR) cross-country public-use flight, under the provisions of Title 14 Code of Federal Regulations (CFR) Part 91, when the accident occurred. N78NR was registered to and operated by the pilot as a VFR cross-country flight under the provisions of Title 14 CFR Part 91. The sole occupants of the airplanes, both certificated commercial pilots, sustained serious injuries. After the collision, both aircraft descended uncontrolled into an area of densely populated birch and spruce trees and sustained substantial damage. Visual meteorological conditions prevailed in the area at the time of the accident. N82735 departed Wasilla Airport about 1300 bound for Beluga, Alaska, and company flight following procedures were in effect. N78NR departed Birchwood Airport, Chugiak, Alaska about 1250 destined for an off-airport landing site near Johnson Creek with no flight plan on file.

During on-scene interviews with the National Transportation Safety Board (NTSB) Investigator-in-Charge (IIC) on February 1, witnesses consistently reported that they observed one Piper PA-18 traveling in a southwesterly heading, and the other Piper PA-18 traveling in a northwesterly direction. One witness on the ground observed both airplanes converge at approximately a 90 degree angle. The witness said that as both airplanes converged, neither airplane changed altitude or direction as they approached each other, and the two subsequently collided.

During an interview with the NTSB IIC on February 1, a pilot-rated witness that was standing on the east end of South Hollywood Airport, who observed the airplanes just after the collision, stated that he recognized the Alaska State Trooper airplane. He said that after the collision the state trooper's airplane entered a spin, and it began a nose low, spiraling descent. As the airplane reached approximately 400 feet above ground level, the airplane recovered from the spin and briefly leveled off. This was followed by an increase in engine noise. The nose of the airplane then pitched abruptly down, and then the engine noise decreased, which was followed by the sound of the airplane impacting the tree-covered terrain. He said that after the midair collision, the other Piper PA-18 appeared to snap roll to the right as the airplane traveled away from his location. He then observed a large portion of that airplane's right wing flutter to the ground, as it entered a near vertical, uncontrolled, spiraling descent.

During a hospital room interview with the NTSB IIC on February 2, the Alaska State Trooper pilot of N82735 stated that after departure from the Wasilla Airport, he climbed the airplane to approximately 1,500 to 2,000 feet MSL, and configured the airplane for cruise flight. While in level cruise flight, traveling in a southwesterly heading, with the sun at his 1130 to 1200 o'clock position, he saw a momentary flash in the upper left corner of his windscreen, which was instantaneously followed by the collision. After the collision his airplane entered an uncontrollable dive, with no elevator control. In a final effort to regain control, he pushed the control stick forward, and he was able to regain limited elevator authority, but the airplane continued to descend, nose low, into the tree-covered terrain. The last thing the trooper pilot remembered was entering the trees.

PERSONNEL INFORMATION

N82735 pilot:

At the time of the accident, the pilot of N82735 was employed by the State of Alaska Department of Public Safety, Alaska State Troopers as a Wildlife Trooper.

The pilot, age 35, holds a commercial pilot certificate with ratings for airplane single engine land, single engine sea and instrument airplane. His most recent second class medical certificate was issued on September 04, 2014, and contained the limitation that he must wear corrective lenses.

According to records provided by the State of Alaska Department of Public Safety, he had logged about 543 hours of flight experience at the time of the accident. He also passed a currency checkride on September 04, 2014.

N78NR pilot:

The pilot of N78NR, age 52, holds a commercial pilot certificate with an airplane single engine land rating with the limitation "the carriage of passengers for hire in airplanes on cross country flights in excess of 50 nautical miles or at night prohibited." His most recent third class medical certificate was issued on March 07, 2013, and contained the limitation that he must wear corrective lenses.

No personal flight records were located for the pilot, and the aeronautical experience listed on page 3 of this report was obtained from a review of the airman's Federal Aviation Adminitration (FAA) records on file in the Airman and Medical Records Center in Oklahoma City, Oklahoma. On the pilot's last application for a medical certificate, dated March 07, 2013, he indicated that his total aeronautical experience consisted of about 1400 hours.

AIRCRAFT INFORMATION

N82735:

The airplane was a Piper PA-18-150, manufactured in 1977 and equipped with a Lycoming O-320 series engine.

The colors of the airplane included a primary base color of white with red accent lines, red wings, and a red propeller spinner.

At the time of its last annual inspection, completed on October 14, 2014, the airplane had 7,851 hours in service.

N78NR:

The airplane was a Piper PA-18-150, manufactured in 1956 and equipped with a Lycoming O-320 series engine.

The colors of the airplane included a primary base color of white with red accent lines, white wings and a red propeller spinner.

No airplane and engine log books were discovered for examination.

METEOROLOGICAL INFORMATION

The closest weather reporting facility is Wasilla Airport, about 5 miles northeast of the accident sites. At 1256, an aviation routine weather report (METAR) at Wasilla, Alaska, reported: wind, 250 at 4 knots; visibility, 10 statute miles; sky condition, clear; temperature, 12 degrees F; dew point 1 degrees F; altimeter, 30.37 inHG.

COMMUNICATIONS

Both airplanes transceivers were recovered and sent to the NTSB Vehicle Recorders Laboratory in Washington, D.C. for recovery of the last active and standby frequencies.

Postaccident operational testing of the transceiver recovered from N82735 revealed a primary active radio frequency of 122.80 Mhz, and a non-active secondary frequency 135.25 Mhz.

Postaccident operational testing of the transceiver recovered from N78NR revealed a primary active radio frequency of 122.80 Mhz, and a non-active secondary frequency 123.00 Mhz.

In May of 2014, following a series of midair collisions in the Matanuska Susitna (Mat-Su) Valley, the FAA made significant changes to the common traffic advisory frequencies (CTAF) assigned north and west of Anchorage, AK. The FAA established geographic CTAF areas based, in part, on: flight patterns, traffic flow, private and public airports and off-airport landing sites. The CTAF for the area where the accident occurred was 122.80 Mhz.

Both airplanes were operating in "Class G" airspace, and there is no regulatory requirement for either airplane to be equipped with two-way radio communications.

WRECKAGE AND IMPACT INFORMATION

The NTSB IIC, along with three other NTSB investigators, a FAA safety inspector from the Anchorage Flight Standards District Office (FSDO), and the Alaska State Troopers reached the accident sites on the afternoon of January 31.

N82735:

All of the airplanes major components were located at the main wreckage site. The wreckage was located in an area of densely populated spruce and birch trees, on its left side at an elevation of about 335 feet mean sea level (MSL). The nose of the airplane was on about a 225 degree heading (All headings/bearings noted in this report are magnetic).

Numerous pieces of cut trees and brush were observed at the accident site, and on both the left and right side of the wreckage forward of the engine. Examination of these cuts revealed flat angular fractures with black paint transfer marks.

The cockpit area was extensively damaged. The engine and firewall were displaced upward and aft, and the instrument panel was displaced upward. The throttle was found in the near closed position. The mixture was full rich, and the carburetor heat was in the off position.

The exhaust tube had malleable bending and folding, producing sharp creases that were not cracked or broken along the creases.

The airplane's left wing separated near its fuselage attach points, exhibited extensive impact damage, and came to rest underneath and intertwined with the outboard portion of N78NR right wing. The wing strut remained attached to its respective wing and fuselage attach points, but was found embedded in the internal structure of N78NR right wing.

The airplane's severed right wing exhibited extensive impact damage, and came to rest inverted and parallel to the fuselage.

Both the left and right aileron remained attached to their respective attach points, but exhibited extensive spanwise accordion style crushing.

The left horizontal stabilizer and elevator remained attached to their respective attach points and were relatively undamaged. The right horizontal stabilizer exhibited extensive leading edge crushing along the entire span of the stabilizer. The right elevator exhibited spanwise bending from the tip inboard. The vertical stabilizer and rudder remained attached to their respective attach points, but exhibited extensive impact damage.

Both propeller blades remained attached to the engine crankshaft. One propeller blade exhibited leading edge gouging, su...