Controlled Flight into Terrain: Cessna U206G Stationair, N732DF; fatal accident occurred December 10, 2017 near Molokai Airport (PHMK), Kaunakakai, Hawaii

View of the fuselage and engine. 
National Transportation Safety Board

View of the flight track information.
National Transportation Safety Board

View of the termination of the flight track information.
National Transportation Safety Board

View of the accident site on a clear day, looking to the northwest.
National Transportation Safety Board

View of the fuselage and the empennage.

National Transportation Safety Board

Federal Aviation Administration aviation weather camera in Alaska.

Exemplar: Gustavus Airport (GST), Gustavus, Alaska, Federal Aviation Administration aviation weather camera coverage areas.
Federal Aviation Administration

Exemplar: Gustavus Airport (GST), Gustavus, Alaska, FAA aviation weather camera (southeast) clear day.
Federal Aviation Administration

Exemplar: Gustavus Airport (GST), Gustavus, Alaska, FAA aviation weather camera (southeast) instrument meteorological conditions image.
Federal Aviation Administration

Designated mountainous terrain in Hawaii.
Electronic Code of Federal Regulations

The National Transportation Safety Board traveled to the scene of this accident.

Additional Participating Entities:
Federal Aviation Administration / Flight Standards District Office; Honolulu, Hawaii
Textron Aviation; Wichita, Kansas
Continental Motors; Mobile, Alabama

Aviation Accident Final Report - National Transportation Safety Board: https://app.ntsb.gov/pdf

Investigation Docket - National Transportation Safety Board: https://dms.ntsb.gov/pubdms

http://registry.faa.gov/N732DF

Location: Maunaloa, HI
Accident Number: ANC18FA012
Date & Time: 12/10/2017, 1105 HST
Registration: N732DF
Aircraft: CESSNA U206
Aircraft Damage: Destroyed
Defining Event: Controlled flight into terr/obj (CFIT)
Injuries: 2 Fatal
Flight Conducted Under: Part 91: General Aviation - Personal 

Analysis 

The instrument-rated private pilot was conducting a personal flight under visual flight rules (VFR) from one island to the airplane's home base on another island with one passenger onboard. The airport's automated weather observation system reported marginal VFR (MVFR) conditions throughout the morning of the accident, and an AIRMET Sierra was valid for the area of the accident site for mountain obscuration, widespread MVFR ceilings, and scattered rain showers. However, there was no evidence to suggest that the pilot had obtained a weather briefing from an official, access-controlled source before departing on the flight. While en route and receiving VFR flight following services from air traffic control, the pilot requested an instrument (VOR-A) approach to the destination airport. The pilot also reported having the most recent ATIS weather information Juliet, issued at 1055. The ATIS reported 4 miles of visibility with light rain and mist, along with a ceiling of 1,400 ft broken with a broken cloud layer at 3,300 ft. The controller provided the pilot with vectors to initiate the approach and advised him to maintain VFR, which the pilot acknowledged. Two minutes later, the controller issued a frequency change to the destination airport control tower. About 4 minutes after that, the tower controller advised the pilot that the airplane was south of the final approach course. The pilot indicated that he was correcting and was "right at the edge of VFR," but that he had "pretty good visibility." There were no further communications from the accident airplane and radar contact was lost shortly thereafter.

The airplane impacted remote mountainous terrain about 1,285 ft msl and about 3.35 miles southwest of the runway threshold at the destination airport; the airplane was destroyed by a postimpact fire. Postaccident examination of the airframe and engine revealed no evidence of preimpact mechanical anomalies that would have precluded normal operation. A photo taken by first responders about 1.5 hours after the accident showed a low cloud layer at the accident site.

Damage to 20-ft-tall trees indicated that the airplane impacted them and then struck a second set of trees that were about 15 ft tall. Multiple tree branches with propeller cut marks were found along the wreckage path. The wreckage was located on the western side of a ridge with dirt and low growth vegetation that crested about 100 ft above the surrounding area, with about a 50° incline. It is likely that, during the approach, the pilot continued visual fight into an area of instrument meteorological conditions consisting of clouds and showers, which resulted in a loss of visual reference and subsequent controlled flight into terrain.

The pilot's logbook was not available for review, and neither his recency of experience nor instrument experience could be determined. The flight instructor who conducted his most recent flight review, about 8 months before the accident, did not endorse the pilot for instrument flight. Autopsy of the pilot identified severe heart disease, which placed the pilot at risk of sudden acute symptoms such as chest pain, palpitations, shortness of breath, or fainting. Flight track information and the pilot's communication with air traffic control indicate that he was actively maneuvering the airplane, likely to avoid clouds and attempt to remain in visual conditions, until it impacted terrain. Thus, it is unlikely that symptoms from the heart disease contributed to the accident. 

Probable Cause and Findings

The National Transportation Safety Board determines the probable cause(s) of this accident to be:
The pilot's decision to continue visual flight into an area of instrument meteorological conditions while conducting an instrument approach, which resulted in a loss of visual reference and subsequent controlled flight into terrain. 

Findings

Aircraft
Altitude - Not attained/maintained (Cause)
Descent/approach/glide path - Not attained/maintained (Cause)

Personnel issues
Aircraft control - Pilot (Cause)
Decision making/judgment - Pilot (Cause)

Environmental issues
Ceiling/visibility/precip - Decision related to condition (Cause)
Ceiling/visibility/precip - Effect on operation (Cause)

Factual Information

History of Flight

Approach-circling (IFR)
Loss of visual reference
Controlled flight into terr/obj (CFIT) (Defining event)

Post-impact
Fire/smoke (post-impact)

On December 10, 2017, about 1105 Hawaii-Aleutian standard time (HST), a Cessna U206G airplane, N732DF, impacted remote mountainous terrain during an instrument approach to Molokai Airport (MKK), Kaunakakai, Hawaii. The private pilot and passenger sustained fatal injuries, and the airplane was destroyed by a postimpact fire. The airplane was registered to the pilot who was operating it as a Title 14 Code of Federal Regulations (CFR) Part 91 personal flight. Day instrument meteorological conditions (IMC) were reported at MKK at the time of the accident and no flight plan was filed for the visual flight rules (VFR) flight, which originated from Daniel K. Inouye International Airport (HNL), Honolulu, Hawaii, about 1030.

The pilot and his wife were returning to their home on Molokai at the time of the accident. Radar and air traffic control information from the Federal Aviation Administration (FAA) indicated that the pilot departed HNL and obtained VFR flight following services from the Honolulu Combined Control Facility (HCF). The pilot flew to the west side of Molokai as shown below in figure 1. About 1050, the pilot requested the VOR-A instrument approach at MKK. The pilot was instructed to maintain VFR and was issued a heading change, which he acknowledged. At 1053, the MKK tower controller informed HCF who was communicating with the airplane, that MKK was "IFR." At 1055, the pilot advised the controller that he had obtained the most recent weather information at MKK (ATIS information Juliet); the pilot was then cleared for the approach at 1056 and instructed to contact MKK tower at 1058.

Figure 1 – Flight track information.

After making several turns on the west side of Molokai, the flight continued south and then began a turn to the east toward MKK as shown below in figure 2. About 1101, when the airplane was about 6 miles from the runway, the tower controller advised the pilot that he was south of the final approach course. The pilot responded that he was "coming back," that he was "right at the edge of VFR," and that he had "pretty good visibility." No further communications were received from the accident pilot, and radar contact was lost shortly thereafter.

Figure 2 – Flight track information.

At 1106, the MKK tower controller informed HCF that they had lost radar and radio communications with the pilot. The MKK tower controller also notified local first responders on Molokai. The wreckage was located by the Maui County Fire Department at 1213, about 3.35 miles southwest of the airport.

The pilot of another airplane reported that he had planned to fly from HNL to MKK the day of the accident and departed shortly after the accident pilot. Before departing, he checked weather radar information and saw precipitation on the north side of Molokai but stated that MKK was reporting VFR. He was receiving VFR flight following services, and, after departing HNL airspace, the controller notified him that MKK was under instrument conditions. The pilot, who was not instrument rated, chose to return to HNL and landed there without incident.

William and Lynn Vogt

Pilot Information

Certificate: Private
Age: 79, Male
Airplane Rating(s): Single-engine Land
Seat Occupied: Left
Other Aircraft Rating(s): None
Restraint Used:
Instrument Rating(s): Airplane
Second Pilot Present: No
Instructor Rating(s): None
Toxicology Performed: Yes
Medical Certification: Class 3 With Waivers/Limitations
Last FAA Medical Exam: 03/06/2015
Occupational Pilot: No
Last Flight Review or Equivalent: 04/25/2017
Flight Time: (Estimated) 2697 hours (Total, all aircraft) 

The pilot's logbook was not available for review and his recency of experience could not be determined. The pilot reported 2,697 total hours of flight experience on his most recent application for an FAA medical certificate on March 6, 2015.

An FAA inspector spoke with the flight instructor who conducted the accident pilot's most recent flight review on April 25, 2017. The flight instructor reported that the pilot was a very competent VFR pilot, but he was not proficient in instrument flight. The instructor did not endorse the pilot for an instrument proficiency check. While the pilot held an instrument rating, it could not be determined his recency of instrument experience or his total instrument flight experience in simulated or actual conditions.

Aircraft and Owner/Operator Information

Aircraft Make: CESSNA
Registration: N732DF
Model/Series: U206G
Aircraft Category: Airplane
Year of Manufacture: 1978
Amateur Built: No
Airworthiness Certificate: Normal
Serial Number: U20604662
Landing Gear Type: Tricycle
Seats: 4
Date/Type of Last Inspection:
Certified Max Gross Wt.: 3600 lbs
Time Since Last Inspection:
Engines: 1 Reciprocating
Airframe Total Time:
Engine Manufacturer: Continental Motors
ELT: Not installed
Engine Model/Series: IO-520-F27B
Registered Owner: On file
Rated Power: 300 hp
Operator: On file
Operating Certificate(s) Held:None  

The airplane's maintenance records were not available for review. Review of manufacturer and airworthiness information for the airplane indicated that it was equipped for IFR operations; however, whether the airplane had received the inspections required for IFR flight could not be determined.

There was no evidence that the airplane was equipped with onboard weather equipment or a terrain awareness and warning system (TAWS), nor was it required to be. A heavily-damaged tablet computer was found in the wreckage; however, the pilot's subscription to the ForeFlight application, which was capable of displaying weather and terrain information, had expired several months before the accident.

Meteorological Information and Flight Plan

Conditions at Accident Site: Instrument Conditions
Condition of Light: Day
Observation Facility, Elevation: PHMK, 443 ft msl
Distance from Accident Site: 3 Nautical Miles
Observation Time: 2103 UTC
Direction from Accident Site: 66°
Lowest Cloud Condition: Scattered / 1200 ft agl
Visibility:  6 Miles
Lowest Ceiling: Broken / 1700 ft agl
Visibility (RVR):
Wind Speed/Gusts: 8 knots /
Turbulence Type Forecast/Actual: None / None
Wind Direction: 30°
Turbulence Severity Forecast/Actual: N/A / N/A
Altimeter Setting: 30.04 inches Hg
Temperature/Dew Point: 22°C / 21°C
Precipitation and Obscuration: Moderate - Mist
Departure Point: HONOLULU, HI (HNL)
Type of Flight Plan Filed: None
Destination: KAUNAKAKAI, HI (MKK)
Type of Clearance: VFR
Departure Time: 1030 HST
Type of Airspace: Class D 

The closest weather observation site was located at MKK, about 4 miles northeast of the accident site at an elevation of 443 ft mean sea level (msl). Marginal VFR conditions prevailed at the airport throughout the morning of the accident. The 1006 MKK observation included 6 miles visibility, light rain, mist, broken ceiling at 1,400 ft and 3,300 ft msl, and an overcast ceiling at 5,500 ft msl.

ATIS Juliet reported 4 miles of visibility with light rain and mist, along with a ceiling of 1,400 ft broken with a broken cloud layer at 3,300 ft.

The MKK special weather observation at 1103 reported wind from 030° at 8 knots, 6 miles visibility in mist, scattered clouds at 1,200 ft msl, a broken ceiling at 1,700 ft msl, overcast ceiling at 4,800 ft msl, temperature 71°F, dew point 70°F, and an altimeter setting of 30.04 inches of mercury. The remarks included: automated observation system with a precipitation discriminator, rain ended at 1103, hourly precipitation since 1053 less than 0.01 inches or a trace, temperature 71°F, dew point 69°F. The closest Weather Surveillance Radar-1988 Doppler (WSR-88D) to the accident site was from the National Weather Service (NWS) Molokai (PHMO) antenna, about 1.5 miles west of the accident site. Figures 3, 4, and 5 show base reflectivity images several minutes before and after the time of the accident, with multiple bands of precipitation near the accident site and MKK (in the images below, MKK is referred to as PHMK).

Figure 3 – PHMO WSR-88D 0.5° base reflectivity image at 1057 

National Weather Service 

Figure 4 - PHMO WSR-88D 0.5° base reflectivity image at 1102 

National Weather Service 

Figure 5 - PHMO WSR-88D 0.5° base reflectivity image at 1107 

National Weather Service 

An Area Forecast issued by the NWS at 1030 listed marginal VFR (MVFR) ceilings and scattered showers for the accident site and MKK, and stated in part:

AIRMET SIERRA for MTN OBSC is in effect for Maui, Lanai, Molokai and Oahu. An ENE-WSW frontal cloud band nearly stationary over Maui, Lanai and Molokai will produce widespread MVFR ceilings and scattered showers through the day.

Weather Briefings

A search of official weather briefing sources, such as the Lockheed Martin Flight Service and the Direct User Access Terminal Service, indicated that the pilot did not access these services for preflight weather information.

Airport Information

Airport: Molokai (MKK)
Runway Surface Type: Asphalt
Airport Elevation: 453 ft
Runway Surface Condition: Wet
Runway Used: 05
IFR Approach: Circling; Practice; VOR
Runway Length/Width: 4494 ft / 100 ft
VFR Approach/Landing: Full Stop

MKK is a public airport in class D airspace, located about 6 miles northwest of Kaunakakai, Hawaii, at a surveyed elevation of 454 ft msl. The airport had two runways (5/23 and 17/35) open at the time of the accident. Runway 5/23 was 4,494 ft long and 100 ft wide, and runway 17/35 was 3,118 ft long and 100 ft wide.

Runway 5/23 was equipped with medium intensity runway edge lights, a precision approach path indicator (PAPI), and a medium intensity approach lighting system with runway alignment indicator lights. Runway 5 was also equipped with runway end identifier lights. Runway 5 was serviced by GPS, VOR, and tactical air navigation system instrument approach procedures.

According to the FAA Airport/Facility Directory, the runway 5 PAPI system was not authorized 1.8 nautical miles beyond the landing threshold due to rapidly rising terrain. This document also stated that a mountain, about 1,280 ft msl, was located 2.8 nautical miles from the threshold of runway 5 on the extended centerline, as shown in figure 6. The mountain did not have obstruction lighting in place, nor was it required to.

Figure 6 – Aerial view of the accident site with the wreckage on the mountain in the lower left corner and of runway 5 at MKK at the center top.

Maui County Police Department

A review of NOTAMS found no information on the day of the accident that would have affected the flight to MKK. 

Wreckage and Impact Information

Crew Injuries: 1 Fatal
Aircraft Damage: Destroyed
Passenger Injuries: 1 Fatal
Aircraft Fire: On-Ground
Ground Injuries: N/A
Aircraft Explosion: Unknown
Total Injuries: 2 Fatal
Latitude, Longitude: 21.133056, -157.149722 (est)

The accident site was located in remote, mountainous terrain on the Molokai Ranch, Maunaloa, Hawaii, at an elevation about 1,285 ft msl about 3.35 miles southwest of the MKK runway 5 threshold. A postaccident photograph taken by first responders about 1.5 hours after the accident showed a low cloud layer present at the accident site (see figure 7).

Figure 7 – View of the accident site with a low cloud layer present, shortly after the accident occurred, looking to the northwest.

Maui County Police Department

The wreckage was located on the western side of a ridge with dirt and low growth vegetation that crested about 100 ft above the surrounding area, with about a 50° incline. The wreckage was destroyed by a postimpact fire.

Damage to 20-ft-tall trees indicated that the airplane impacted them on a northeasterly heading; it then struck a second set of trees that were about 15 ft tall. Multiple tree branches with propeller cut marks were found along the wreckage path. The wreckage came to rest on a 220° heading. All major structural components of the airplane were accounted for at the accident site. The fuselage from the firewall outward to both wing roots and to the midempennage area was consumed by fire. The leading edges of both wings displayed impact deformation.

Control cable continuity was established from the empennage to the cockpit and from both wings to the cockpit. The flaps were found in the retracted position. The elevator trim tab was found at the 15° trailing edge up position.

The fuel strainer screen and fuel strainer bowl were both found clean. The fuel selector handle was not located. The top of the shaft from the fuel selector handle to the fuel selector valve was melted by the fire. The fuel selector valve was found in the right tank position. Most of the fuel system was consumed by fire damage.

Most of the cockpit instrumentation was destroyed by fire. The altimeter Kollsman window was found at a setting of 30.25. The heading indicator was found at 350°. The heading bug was found at 270°. Rotational scoring was observed on the attitude indicator gyro consistent with rotation at the time of impact.

Both occupant seats and seat restraint systems, along with the rest of the cabin furnishings, were consumed by fire.

The engine was intact and sustained impact and thermal damage. All three metal propeller blades were located underneath the cockpit area and remained attached to the engine crankshaft. One propeller blade was bent aft, another blade exhibited s-bending, and the third blade had a partially separated tip.

No preimpact mechanical malfunctions or failures of the airframe were noted that would have precluded normal operation.

The engine was recovered from the site for further examination. Internal continuity was established. No preimpact mechanical malfunctions or failures of the engine were noted that would have precluded normal operation.

Medical And Pathological Information

The pilot reported to the FAA having a superficial venous thrombosis in 2014. The pilot's last FAA medical certificate expired on March 31, 2017. The family of the pilot provided a completed copy of the FAA Form 8700-2 Comprehensive Medical Examination Checklist to the NTSB and FAA, which is used during the FAA BasicMed qualification process; however, review of FAA records revealed that the pilot did not complete all the requirements for the BasicMed program.

Pacific Pathologists, LLC, Wailuku, Hawaii, conducted an autopsy of the pilot. The cause of death was attributed to multiple blunt force injuries. Severe coronary atherosclerosis with 50-90% stenosis of the left anterior descending coronary artery, 50% stenosis of the circumflex, and 50-80% stenosis of the right coronary artery with evidence of previous ischemia demonstrated by fibrosis of the posterior papillary muscle was identified. The leg veins previously diagnosed with venous thrombus could not be evaluated due to the extent of injury, but there was no evidence of pulmonary thromboemboli.

Toxicology testing performed at the FAA Forensic Sciences Laboratory on specimens from the pilot were negative for carbon monoxide, ethanol, and drugs. Cyanide tests were not performed.

Additional Information

Controlled Flight into Terrain (CFIT)

FAA Advisory Circular 61-134, General Aviation Controlled Flight into Terrain Awareness, discusses the risk that CFIT poses for pilots and states in part:

CFIT occurs when an airworthy aircraft is flown, under the control of a qualified pilot, into terrain (water or obstacles) with inadequate awareness on the part of the pilot of the impending collision.

The importance of complete weather information, understanding the significance of the weather information, and being able to correlate the pilot's skills and training, aircraft capabilities, and operating environment with an accurate forecast cannot be emphasized enough.