N928JP

HISTORY OF FLIGHTOn April 13, 2022, about 0832 mountain daylight time (MDT), a Cessna 208B Grand Caravan, N928JP, was substantially damaged when it was involved in an accident near Heyburn, Idaho. The pilot was fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations (CFR) Part 135 cargo flight.

The pilot was transporting cargo on an instrument flight rules (IFR) flight from Salt Lake City International Airport (SLC) Salt Lake City, Utah to Burley Municipal Airport (BYI), Burley, Idaho under the call sign Gem Air 1826. According to ForeFlight records, the pilot received an online weather briefing for BYI at 0506 on the morning of the accident and filed an IFR flight plan from SLC to BYI at 0553.

The flight plan indicated a proposed departure time of 0700 and an estimated time en route of 1 hour and 7 minutes at an altitude of 12,000 ft above mean sea level (msl) with 4 hours of fuel onboard. According to ADS-B data, the airplane began to taxi at SLC about 0655 and departed runway 16L about 0700. The climb and en route portions of the flight to BYI were uneventful.

ADS-B data and winds aloft were used to capture the airplane’s altitude, position, and airspeed during the initial portions of the two approaches to BYI runway 20. The ADS-B data ended about 4,800 ft msl, or about 660 ft above ground level (agl), which was about the time the airplane approached the JAMID stepdown fix. After passing JAMID, a performance study was used for calculating data.

As the airplane approached BYI, the air traffic control (ATC) approach controller issued the pilot the current altimeter setting and verified that the pilot had the current weather for BYI; the controller then cleared the pilot for the RNAV runway 20 approach via the MALTT transition at MUTOE (Figure 1).

Figure 1. BYI RNAV (GPS) Runway 20 Approach Chart.

The pilot reported passing the MALTT and MUTOE waypoints along the published approach, and at 0807:27 and 7,000 ft reported at IREME, the initial approach fix (IAF) for the approach. Subsequently, ATC provided the pilot with instructions for cancelling the flight’s IFR flight plan and cleared the pilot to switch to the BYI airport advisory frequency.

After turning onto the final approach course at IREME, the airplane maintained about 7,000 ft until about 2.5 nm past IREME. The airplane then began to descend at about 200 ft/min (fpm) until about 6,800 ft, where the airplane intercepted a 3.75° glide path to runway 20. During this initial descent, the computed calibrated airspeed was between about 128 and 132 knots calibrated airspeed (KCAS).

The airplane remained on a glide path of about 3.75° while the rate of descent increased to between 1,000 and 1,100 ft per minute (fpm) and the airspeed increased, peaking at about 156 KCAS. The airspeed then started to decrease continuously, reaching 141 KCAS as the airplane descended below ADS-B coverage near JAMID, about 1.6 nm from the displaced threshold. Between 0810:55 and 0811:27, the rate of descent decreased from about 1,100 to about 960 fpm.

At 0812:23, a surveillance video at BYI recorded the airplane flying wings-level about 20 ft agl over the runway, with the flaps up, about 2,328 ft. beyond the runway 20 displaced threshold. Snow was observed falling and was covering the runway in view. The airplane’s ground speed was about 91 knots at this time.

About 0813:56 the pilot reported initiating a missed approach. After the pilot declared a missed approach, ATC asked for the pilot’s intentions. The pilot requested the same approach and ATC instructed the pilot to report when the flight was established in the hold at IREME and to expect the RNAV runway 20 approach.

At 0819:46 the pilot reported being established in the hold at IREME. ATC cleared the pilot for the RNAV runway 20 approach and instructed the pilot to cross IREME inbound at 7,000 ft, and to report crossing IREME inbound. The pilot reported crossing IREME inbound while on a track of 218° true and at a ground speed of 122 knots.

Upon reaching a point 1 nm past IREME, the pilot started a descent of about 120 fpm. At 0828:30, the rate of descent increased to about 500 fpm. Between 0828:25 and 0830:05, the airspeed increased from about 114 KCAS to about 134 KCAS as the airplane descended from 6,830 ft to about 6,000 ft.

At 0830:10, about 6,000 ft, the airplane intercepted the 3.75° glide path to the runway. The rate of descent decreased momentarily to zero before increasing again to about 900 fpm, resulting in the airplane deviating above the 3.75° glide path, and then descending back towards it. The airplane intercepted the 3.75° glide path at 0831:12, about 2.4 nm from the displaced threshold, and remained on that glide path until reaching the JAMID waypoint at 0831:36, at an altitude of 4,800 ft. Between 0830:10 and 0831:36, the airspeed decreased from 133 KCAS to 100 KCAS. The last ADS-B point was recorded at 0832:17; at that point, the airplane was 0.6 nm from the displaced threshold at 4,387 ft (245 ft above the displaced threshold), on the 3.75° glide path to the runway, at an airspeed of about 85 KCAS.

Video footage recovered from a security camera located at the processing plant along the approach to runway 20 showed a view of the rooftop of the processing plant, along with a single vent stack supported by steel framework on the roof. Snow was observed falling, and visible moisture was present in the form of billowing steam clouds emitting from other stacks on the roof of the plant. The stack remained clearly visible in the video, with small sections periodically concealed by the steam clouds. The stack was topped by a warning light, but due to the daylight contrast, and location of the camera below, it could not be determined if it was operating. About 0832:25, the airplane came into view in a wings-level, flaps-up, nose-high descent (Figure 2). The airplane struck the vent stack and fell to the rooftop. The top of the stack was 4,256 ft msl. The airplane struck the stack about 14 ft below the top. The stack was within the lateral boundaries of the approach path, and the distance from the top of the stack to the glide path above it was calculated at 98 ft (Figure 3).

Figure 2. Image from the security camera.

Figure 3. Illustration showing the height of the stack and distance from the glide path to runway 20.

A witness located about 1/4 mile away heard and then observed the airplane descend out of the clouds before it immediately went into a steam cloud produced by a set of six smokestacks located at the processing plant. The witness heard the engine sound increase and saw the nose lift shortly before the airplane struck the vent stack and descended to the rooftop. PERSONNEL INFORMATIONA review of records revealed that on April 9, 2022, the pilot was on duty between 0630 and 1000 and flew a roundtrip from SLC to BYI and logged a total of 2.4 hours in the CE-208B (N928JP).

On April 10, 2022, the pilot was off duty.

On April 11, 2022, the pilot was on duty between 0600 and 1900 and logged a total of 5.0 hours (no routing information was provided).

On April 12, 2022, the pilot was on duty between 0600 and 1030 and was scheduled to fly a roundtrip from SLC to BYI. According to Gem Air LLC interviews, the pilot had to divert from BYI to Joslin Field/Magic Valley Regional Airport (TWF), Twin Falls, Idaho due to "ground icing conditions" at BYI. The pilot logged a total of 3.2 hours in the CE-208B (N928JP) for the day.

On April 13, 2022, the day of the accident, the pilot went on duty at 0600.

The pilot completed initial CE-208B training on November 16, 2021. On February 17, 2022, the pilot successfully completed 14 CFR 135.293, 135.297 and 135.299, proficiency, instrument, and line checks.

The Gem Air pilot training program included standards for performing non-precision instrument approaches. According to the operator’s Flight Maneuvers Description Manual, the non-precision approach section stated, in part, “if you are approaching an airport, without current weather reports, even if the approach is straight-in, you may wish to plan on circling over the airport to check the winds and runway condition.” The document’s standard for airspeed after passing the final approach fix was 120 knots indicated airspeed (KIAS).

According to the Chief Pilot, Gem Air did not teach the pilots to follow the Garmin vertical flight path indicator but did teach pilots to use it as advisory guidance. Gem Air taught pilots to use the autopilot on non-precision approaches in both VNAV and Approach mode. If engaged, the autopilot would follow the vertical path indications when available. Additionally, the Flight Maneuvers Description Manual stated, in part, “After passing the final approach fix inbound, begin descent to MDA [minimum descent altitude] or step-down fix, if applicable. Descent should be approximately 1000 fpm to ensure that you are at the next required altitude. Failure to make the descent to MDA in a timely manner may result in missing the opportunity to visually identify the airport in time to continue a normal descent to landing.”

The pilot calculated the takeoff weight of the accident flight at 8,762.6 pounds and an arm of 201.4, with a fuel load of 140 gallons. Calculations made by Textron Aviation revealed the airplane was within center of gravity limits.

A review of the pilot’s records revealed that she had operated to and from BYI at least 13 times within the year, including the accident flight. AIRCRAFT INFORMATIONAccording to the operator’s Operations Specifications, the accident airplane was authorized to conduct commuter and on-demand operations in IFR/VFR and day/night conditions. The airplane was not equipped with a cockpit voice recorder or a flight data recorder, nor was it required to be.

The airplane had an S-1 Icing Supplement to the Pilot’s Operating Handbook that was applicable to airplanes equipped with the TKS Ice Protection System and a cargo pod, such...