History of Flight
On July 26, 2021, at about 1320 Alaska daylight time, a Cessna 172P airplane, registration N65698, was substantially damaged when it crashed near Eagle River, Alaska. The flight instructor and private pilot received fatal injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 instructional flight by Angel Aviation Inc., Anchorage, Alaska.
The flight originated from Merrill Field Airport (MRI), Anchorage, at about 1215. It was reserved as a “discovery flight” scheduled from 1200 to 1400. After departure, the airplane proceeded northbound near Palmer, Alaska, then turned towards the Knik Glacier. When the airplane did not return to MRI, a concerned family member used a tracking application that showed the airplane had stopped moving in the Eagle River Valley area and notified authorities.
At about 1700, an alert notice (ALNOT) was issued and a search initiated. The wreckage was located about 2245 in an area of steep, rising glacial terrain at an elevation of about 3,100 feet mean sea level. Although the ALNOT listed a destination of Girdwood, Alaska, the flight had been planned to return to MRI; the reason for the Girdwood listing could not be determined.
Meteorological Information
The National Weather Service sounding from Ted Stevens Anchorage International Airport (PANC) at 1600 depicted a lifted condensation level (LCL) and level of free convection at 3,294 feet above ground level (agl), with a convective condensation level at 4,623 feet agl. This supported few to scattered clouds at the LCL at about 2,700 feet agl and a broken layer about 4,600 feet agl. The freezing level was above 8,000 feet. The sounding indicated several temperature inversions below 10,000 feet, with the atmosphere characterized as stable (lifted index 3.4) and precipitable water content of 0.79 inches. The sounding supported a moderate to severe risk of carburetor icing from the surface through 7,000 feet, based on temperature and relative humidity profiles.
A carburetor icing probability chart for conditions reported at Birchwood Airport (similar to other nearby stations) indicated a moderate risk of serious carburetor icing at cruise power and severe at glide power, bordering the severe category for serious icing at any power setting.
Wreckage and Impact Information
The airplane sustained substantial damage to the fuselage and left wing. A post-accident examination revealed all major components remained attached at their respective attach points. The propeller remained attached to the crankshaft; each blade was missing about 2 inches of the tip and exhibited leading-edge gouging, torsional twisting, chordwise striations across the cambered surface, and trailing edge “S” bending. Flight control continuity was established from all control surfaces to the cockpit. Internal engine continuity was confirmed through propeller rotation. The carburetor, induction system, and airbox were free of pre-impact obstructions to airflow. The carburetor “heat valve” was observed in the ON/HOT position and was “captured” due to deformation of the surrounding heat box material from impact.
Medical and Pathological Information
At the time of the accident, the flight instructor was wearing an Apple Watch that recorded pulse data. The last recorded pulse data recovered from the watch were from between 1500 and 1600 on the day of the accident. The level of accuracy of the pulse recording was unknown.
Survival Aspects
The airplane was equipped with an Ameri-King Corporation AK-451-2 emergency locator transmitter (ELT) marked certified to TSO C-126 and C091(a). The ELT remained secure in its cradle with wires and antenna attached. During the search, no signals were received from the 406 MHz or 121.5 MHz system. The day after the accident, when no personnel were near the wreckage, the ELT began emitting a signal received by the Alaska Rescue Coordination Center. During post-accident testing, when set to “ON” mode, the ELT activated and transmitted on both frequencies. When set to “ARMED” mode, it transmitted only once out of numerous tests.
In 2015, the FAA determined that Ameri-King Corp. manufactured, sold, or distributed parts and articles for installation on FAA type-certificated aircraft that did not conform to an approved design but were represented as FAA-approved. On December 28, 2015, the FAA issued an emergency cease-and-desist order terminating Ameri-King’s technical standard order authorization and parts manufacturer approval. The order required immediate cessation of manufacturing, selling, distributing, advertising, repairing, rebuilding, and altering articles for type-certificated aircraft. The FAA stated it was not confident that parts manufactured by Ameri-King prior to December 28, 2015, were manufactured in accordance with approved design.
The FAA subsequently issued an unapproved parts notification and airworthiness directive (AD) applicable to the ELT model installed. AD-17-16-01 stated that it was prompted by multiple reports of ELT failure and noncompliance to quality standards, noting that failure to correct could delay or impede rescue. The AD required a testing process within 12 months of issuance and repeated at intervals not exceeding 12 months.
A review of the aircraft maintenance records showed an entry dated January 3, 2020, indicating compliance with AD-17-16-01: “Replaced ELT with Artex ELT 1000 P/N A3-06-2749-1 battery due 12/2026.” An entry dated January 22, 2021, stated: “Tested ELT IAW 91.207(d), ELT battery due 12/2026. AD compliance sheet verified and up to date.”