N777GYCessna 320E · 1968

On June 15, 2016, about 1409 mountain daylight time, a Cessna 320E airplane, N777GY, was destroyed when it impacted terrain near Mineral County Memorial Airport (C24), Creede, Colorado. The commercial pilot and two passengers were fatally injured. The airplane was registered to Left Hand Financial, Inc., and was being operated by Rocky Mountain Aerial Surveys (RMAS) under contract with the U.S. Department of Agriculture (USDA) as a Title 14 Code of Federal Regulations Part 91 aerial photography flight. Day visual meteorological conditions prevailed, and no flight plan had been filed for the flight, which departed Central Colorado Regional Airport (AEJ), Buena Vista, Colorado, about 1307.

According to an RMAS employee, about 1240, the pilot called the RMAS base in Longmont, Colorado, to provide a mid-day briefing. The pilot reported that the airplane had performed "fine" for the first 2.5 hours of surveying. However, he added that, after they had lunch at AEJ and departed about 1307, the airplane experienced an engine vibration that felt like it was coming from the right side and that the airplane seemed slow. According to the AEJ manager, about 15 minutes after takeoff, the pilot called AEJ to report that he had an issue and would be returning to the airport. After the pilot landed the airplane at AEJ, he and a local mechanic inspected it to determine what was causing the vibration. The pilot called the RMAS base, and the RMAS employee and the pilot agreed that he would fly to Rocky Mountain Metropolitan Airport (BJC), Longmont, Colorado, for maintenance but that he would call the RMAS base to provide an update on the mechanics' findings before departing AEJ. The RMAS base received no further communications from the pilot.

A Garmin GPSMAP 396 was found near the wreckage and was submitted for examination by the NTSB Vehicle Recorders Division for pertinent data for the accident flight. The data started at 1307:41 and ended at 14:09:27. The data showed that the airplane departed AEJ about 1307 and followed highways, first traveling south away from the operator's base (93 miles northeast), then turning west over Del Norte, Colorado, and then turning northwest toward Creede. Approaching C24, the airplane overflew one aerial survey point just north of the airport. The airplane was between 11,300 to 13,000 ft above mean sea level (msl) and at a groundspeed of between 120 to 169 knots for much of the approximate 1-hour flight. However, during the last 2 minutes of the flight, the airplane passed north of C24, then circled around to the south side of the airport. During this time, the airplane was descending, and the groundspeed decreased from 141 knots to 119 knots to 98 knots, before increasing to 128 knots and then rapidly decreasing to 99 knots during a sharp, 90º left turn to the north. The last recorded data were at 1409:27, at which time the airplane was at a GPS altitude of 8,665 ft with a ground speed of 99 knots. Due to data buffering on the GPS unit, the data recording may have ended before the accident event. Figures 1 and 2 are graphical overlays showing about the first hour and the last 3 minutes of the airplane's flightpath, respectively.

Figure 1. A graphical overlay showing the accident flightpath. (GPS Time recorded in UTC (MDT +6 hours))

Figure 2. A graphical overlay showing the last 3 minutes of the airplane's flightpath. (GPS Time recorded in UTC (MDT +6 hours))

One witness reported seeing the airplane making a left base turn for approach to runway 25 at C24. Another witness stated that the airplane was at a "very low altitude for his position in the pattern," that the propellers were turning, and that the airplane then yawed, returned to a wings-level position, and continued to descend until impacting the ground. Another witness stated that the airplane did not appear to be "far enough out to line up appropriately with the runway." Two witnesses stated that the landing gear were up. One witness, who lived near the accident location, reported that the airplane flew about 10 ft above her house, that it then veered left, and that it was making "loud revving noises." However, two other witnesses located about 1/4 mile west of the accident site reported that they did not hear engine noise.

The accident site was located 0.7 miles from east of runway 25 at C24; which was southwest of AEJ, while BJC was located northeast of AEJ.

The pilot held a commercial pilot certificate with airplane single- and multiengine land and instrument ratings. The pilot's most recent Federal Aviation Administration (FAA) second-class medical certificate was issued on June 22, 2015, with the limitation that he "must have available glasses for near vision." On his medical certificate application, the pilot reported that he had about 1,591 total hours of flight experience, with 230 hours in the previous 6 months. The pilot reported no significant medical conditions and no use of medications to the FAA.

According to the pilot's logbook, his first flight in a Cessna 320 was in the accident airplane on August 20, 2015. The pilot accumulated 28.9 hours of experience in the airplane between August 20 and September 16, 2015. He accumulated an additional 71.5 hours in the airplane between April 12 and May 5, 2016, for a total of 100.4 hours of experience in the Cessna 320. The pilot had 1,985.1 hours total flight experience, with 295.1 hours in multi-engine airplanes. His last flight review was completed on July 7, 2014, in a Cessna 182.

According to FAA records, the low-wing, turbocharged, twin-engine airplane, serial number 320E0027, was issued its original airworthiness certificate on September 3, 1966, and was registered to the operator on September 6, 2011. The airplane had been reconfigured from its original six-seat configuration to a three-seat configuration to allow space for the use of an aerial camera and survey equipment.

According to the airplane's maintenance records, Western Plains Aviation, LLC (WPA), completed the last annual inspection on March 23, 2016, at a recorded Hobbs time of 572.7 hours. The last maintenance entry for the airframe was on June 6, 2016, at a Hobbs time of 789.6, after the operator reported a vibration in the airplane during flight. WPA found the left and right main gear doors were loose and repaired the gear doors and engine nacelle lower skins. Also completed during this maintenance was installation of a Heli-Coil in the left engine oil drain pan, as described below, and replacement of an inoperative left-hand gear indicator switch.

On March 21, 2016, at a time since major overhaul (TSMOH) of 1,059.3 hours and a Hobbs time of 572.7 hours, Aircraft Cylinders & Engines, Inc. (ACE), disassembled and repaired the right engine after the mechanic found spalled lifters during a top overhaul. The engine was reinstalled on the airplane using the existing engine mounts, hoses, and turbocharger components. The last maintenance entry for the right engine was dated April 1, 2016, at a Hobbs time of 573.5 hours and indicated that the right engine cowl flaps had been adjusted.

On June 19, 2013, at a Hobbs time of 2,698.1 hours and a TSMOH of 1,703.7 hours, ACE removed, repaired, and then reinstalled the left engine's Nos. 2 and 4 cylinders. According to the records, a new Hobbs meter was installed sometime in 2014; an entry dated December 12, 2014, listed the Hobbs time as 0, the engine total time as 6,698.5 hours, and the TSMOH as 2,051.5 hours. On March 15, 2016, at a Hobbs time of 572.7 hours, ACE overhauled the left engine and installed overhauled turbocharger components. The engine was installed in the left nacelle with new hoses and new engine mounts on March 23, 2016. The last maintenance entry was dated June 6, 2016, at a Hobbs time of 789.6, and it reported WPA installed a Heli-Coil in the left engine oil drain pan. The airplane was equipped with two Hobbs meters (one that recorded total flight operations and another that recorded revenue flight operations). The airplane Hobbs meter was missing after the accident, only the revenue Hobbs meter was observed after the accident; it indicated 770.6 hours.

After the right and left engine were overhauled in March 2016, an RMAS pilot ferried the airplane back to its base at BJC. During the ferry fight, the pilot noticed a vibration in the airplane, which he later determined was coming from the left side after landing. The pilot ferried the airplane back to WPA the following day where maintenance personnel determined that the fuel manifold valve was leaking. The fittings on the fuel divider were tightened, and according to the RMAS pilot, the return ferry flight to BJC on June 13, 2016, was "smooth and vibration free." Two days later, on the day of the accident, after takeoff from BJC, an RMAS pilot asked the accident pilot how the airplane was performing. The accident pilot reported that it was operating "real smooth."

The airplane struck willow bushes and then the ground about 3,500 ft east-southeast of runway 25 at C24. Based on airplane deformation and impact signatures, the airplane impacted in a slightly nose-low, left-wing-low attitude. The outboard 5 ft of the left wing separated from the inboard wing during impact. The fuselage had slid right and came to rest with the right wing folded underneath the fuselage. The aft fuselage was observed compromised just forward of the empennage section. No fire was observed at the wreckage site.

Airframe

Flight control and trim continuity were established from the control surfaces to the forward cabin and cockpit controls. The rudder balance weight had separated from the top of the rudder and was found at the initial ground contact location. The rear flap actuator chain remained on the sprocket and was observed with eight pins on the lower chain, which indicated that the flaps were extended about 15°. The elevator trim actuator indicated a 10º tab-down position, the rudder trim actuator indicated a neutral position, and the aileron trim actuator indicated a 10º tab-up position. The landing gear actuator was found in the retracted position, and the landing gear was stowed.

The fuel tank system in the Cessna 320F consist of the 2 each main fuel tanks (tip tanks), 2 each auxiliary tanks (in the wing), 2 each fuel valves located outboard of the left and right engines respectively and 2 each fuel selector valve handles located in the cockpit between the pilots and copilots seats. The fuel selector handle for the left engine has 4 positions; Left Main, Left Aux, Right Main, or Left Engine Off. The fuel selector handle for the right engine also has 4 positions; Left Main, Right Aux, Right Main, or Right Engine Off. The fuel selector handles are connected to the fuel selector valves, located outboard of the engines in the wings, by a push-pull cable. The fuel selector valve handles for both the left and right engines, were found in the "Left Main" position. Both fuel selector valves in the wings were found positioned between the main tank position and the auxiliary tank position. The right fuel selector handle position is consistent with the push-pull cable being compromised during impact. The deformation to the left wing would have also compromised the left fuel selector valve position. The left main fuel tip tank remained largely intact and attached to the outboard section of the wing. The baffle installed at the fuel tank attachment fitting was found displaced forward, and the fuel cap was in place. The left auxiliary wing fuel tank exhibited impact damage to the outboard section, and the fuel cap was in place. The right main fuel tip tank had separated from the wing into three sections: the area forward of the fuel tank attachment fitting, the section aft of the fuel tank fitting, and the aft fairing. The baffle installed in the fuel tank attachment fitting was found displaced forward. The fuel cap was in place. The displacement of the fuel baffles in both main fuel tanks is indicative of the fuel tank containing fuel at the time of the impact. The right auxiliary wing fuel tank was intact, and the fuel cap was in place. Fuel was observed draining from both wings in the area of the auxiliary fuel tanks during the airplane recovery. The fuel strainer screens were free of debris, and the fuel strainer bowl appeared lightly corroded with no blockages present.

The ELT was removed from the aircraft and found to be in the "OFF" position. None of the first responders indicated that they had turned the ELT "OFF".

Left Engine

The left engine remained in the engine nacelle attached to the airframe and engine mounts. The throttle, propeller, and mixture control cables remained attached to their respective control levers.

The magnetos remained attached to their mounting pads, and the ignition harness remained secured to the magnetos, and the lead terminals remained attached to their respective sparkplugs. The fuel lines remained secured to their respective fittings with no signs of leakage noted. The oil lines remained attached to the engine, their controllers, and the turbocharger wastegate actuator with no signs of preaccident leakage noted. The manifold pressure and upper deck reference lines remained in place and intact. The left engine examination revealed no preimpact mechanical malfunctions or failures that would have precluded normal operation.

Right Engine

The right engine remained in the engine nacelle but was separated from all four engine mounts. The throttle, propeller, and mixture control cables remained attached to their respective control levers; however, the throttle and mixture control levers were deformed.

Most of the oil had drained from the engine. Both magnetos were separated from their mounting pads, and portions of their flanges remained secured under the mounting hardware.

The fuel lines remained secured to their respective fittings, but two of the fuel fittings were fractured, with no signs of preaccident staining or leakage. The oil lines remained attached to the engine, their controllers, and the turbocharger wastegate actuator with no signs of preaccident leakage noted. The manifold pressure and upper deck reference lines remained secured to their fittings, but some of the fittings were fractured. The right engine examination revealed no preimpact mechanical malfunctions of failures that would have precluded normal operation.

Propellers

The left three-bladed variable-pitch propeller remained attached to the crankshaft propeller flange. The propeller spinner remained in place over the propeller hub and exhibited deformation and crushing damage on one side. All three propeller blades remained attached to the hub; however, one propeller blade was rotated about 180° in the hub, consistent with a pitch change link fracture. That blade was bent aft near its shank with paint erosion on the leading and trailing edges in a chordwise orientation, accompanied by spanwise gouges and scrapes overlying the chordwise erosion. The other two blades were also bent aft and exhibited chordwise paint erosion and scrapes near the tip along with a deep leading-edge gouge, and the other exhibited chordwise paint erosion on the leading and trailing edges and spanwise scrapes and paint erosion in the bent area.

The right three-bladed variable pitch propeller remained attached to the crankshaft propeller flange by one bolt. The other bolts were stripped form the backside of the propeller hub. The propeller flange was fractured on one side. The propeller spinner remained in place, but it was fractured and deformed over all sides of the propeller hub. The three propeller blades remained attached to the hub; however, one blade was rotated within the hub consistent with a pitch change link fracture. All three blades exhibited chordwise paint erosion and scraping, and one blade exhibited spanwise scrapes and paint erosion overlying the chordwise erosion. One blade was twisted toward low pitch and exhibited deep leading-edge gouges.

The El Paso County Coroner, Colorado Springs, Colorado, conducted an autopsy of the pilot and determined that the cause of death was "multiple blunt force injuries." Additionally, the autopsy noted that the pilot had an enlarged heart and moderate two-vessel coronary artery disease. However, there was no evidence of scarring or inflammation of the heart muscle. Additionally, toxicology testing detected tetrahydrocannabinol carboxylic acid (THC-COOH), which is one of the inactive metabolites of tetrahydrocannabinol carboxylic (THC), marijuana's primary impairing psychoactive drug, in the urine and less than 50 ng/ml of the sedating antihistamine diphenhydramine in femoral blood.

The FAA's Bioaeronautical Sciences Research Laboratory, Oklahoma City, Oklahoma, also conducted toxicology testing on the pilot. The testing detected diphenhydramine in urine but not at reportable levels in cavity blood. Additionally, THC was detected in liver and lung but not at reportable levels in cavity blood.

THC-COOH was detected at 20 ng/ml in urine, 12.4 ng/g in liver, and 17 ng/ml in cavity blood and lung. The detected levels of diphenhydramine and THC would likely not have caused impairment.

The USDA contract specified flight altitude and orientation for survey photographs. It stated that for sites of 500 acres or less, the photography flights shall be flown at flight altitudes "designed to achieve a nominal photographic scale of 1:7,920, with a nominal flight altitude above ground of 3,960 ft with a 6 ft focal lens." For sites more than 500 acres, "the nominal photographic scale is 1:12,000, with the nominal flight altitude above ground elevation of 6,000 ft." It added that deviation from the specified flight altitude shall not exceed 2% low or 3% high and that the flight orientation could either be north-south or east-west and that the allowable horizontal deviation from the site center was 356 ft.

Figure 3. Photograph survey locations near accident flight path

Engine Test Runs

Both engines were removed from the wreckage at the recovery facility and sent to the Continental Motors Inc (CMI) factory in Mobile, Alabama for engine examinations and test runs in an engine test cell under National Transportation Safety Board (NTSB) oversight.

Left Engine

The left engine was placed in a test cell, and it started without hesitation but would not produce full power. When the engine was shut down, it was noted that the left cylinder's upper deck reference line b-nut was stripped and would not seal. Review of photographs taken at the recovery facility revealed that the b-nut was in place and that the torque putty was intact following the accident. The b-nut had to be removed to facilitate the removal of the cooling baffle, and the b-nut was likely damaged during this time. The upper deck reference line b-nut was replaced to complete the run.

The engine was started again and run throughout various power settings, including full power, for 30 minutes. Throughout the test-run, the engine accelerated normally without hesitation, stumbling, or interruption in power and produced rated horsepower.

Curled metal shavings were found in the oil sump and oil filter before the engine test-run. Following the test-run, curled metal shavings were found in the oil filter and in the area of the oil pressure relief valve. The source of the curled metal shavings could not be determined during the engine test-run, but the metal shavings did not appear to affect the engine operation.

Right Engine

Due to a bent throttle interconnecting link rod and a fractured upper deck reference fitting, the throttle body/fuel metering unit from the left engine was used during the test-run of the right engine. The propeller flange was fractured during the accident sequence, so a replacement flange was welded to the crankshaft just forward of the nose seal.

The right engine was placed in a test cell, was started, and ran throughout various power settings, including full power, for 30 minutes. The engine accelerated normally without hesitation, stumbling, or interruption in power and produced rated horsepower.

Following the engine test-run, the original fuel metering unit was placed on the left engine's throttle body after the throttle cam was removed and reinstalled, and the throttle interconnecting link rod was replaced due to deformation damage sustained in the accident sequence. The throttle body and metering unit were reinstalled on the right engine for a second test-run. The engine operated normally with the original metering unit installed during the test run. The engine was held at full power for 5 minutes. Following the engine test-run, the oil filter was removed, and no abnormal contamination or metal production was found.

Following the engine test runs, the oil filter was removed, and the filter element was inspected. There were no signs of abnormal contamination or metal production.

Propeller Exams

The left and right propellers and spinners were packaged by the recovery facility and sent to McCauley Propeller Systems for teardown under NTSB oversight.

Both LH and RH propellers sustained impact damage. The bending, twisting, paint scuffing, and overall propeller assembly damage was typical of that associated with rotation at low to no engine power. The exact engine power levels at impact were not able to be determined.

Both propellers had indications consistent with operating near the low pitch position (~13-14 degrees reference angle measured at the 30" blade spanwise station) at impact. These indications included; 1) witness marks in the LH and RH propeller blade butts consistent with contact with adjacent pitch change hardware, and 2) the position of the blade counterweight imprints in the crushed LH and RH propeller spinners.,

Neither propeller had impact signature markings or component positions indicating their blades were feathered at impact.

Electronic Devices

In addition to the Garmin GPSMAP 396 discussed above, 5 additional electronic devices were found at the accident scene and sent to NTSB Vehicle Recorder Division for examination for pertinent accident-related data:

Device 1: Dell Laptop - The hard drive was removed from the Dell laptop and the drive was imaged using forensic software. No accident pertinent data was found.

Device 2: NovAtel DL-4-RT2W - The data extracted included five different flights. The data included position data (latitude, longitude, height above mean sea level, gps week, and gps seconds), raw ephermis data, and compressed range measurements. The receiver firmware was old so the timestamp could not be correlated to the time of the accident. The flights were then mapped to see if the position data could be correlated to the accident flight. None of the five flights recorded were near the accident flight. The accident flight was not recorded on the Novatel device.

Device 3: Apple iPhone 5s #1 - The Apple iPhone 5s #1 was able to be powered on normally. The phone required a passcode that prevented further data from being downloaded from the device.

Device 4: Apple iPhone 5s #2 (Pilot's Phone) - The device was powered on normally and imaged using forensic software. Prior to the accident on June 15, 2016, the user checked the Aviation Weather Center (aviationweather.gov). At 11:11:00 the user checked the wind and temperature on the website. From 11:11:47 through 11:12:59 the user looked at the satellite imagery. At 11:13:23 the user returned to the Aviation Weather Center homepage. At 11:13:29 the user looked at the Aviation Digital Data Service (ADDS) Terminal Aerodrome Forecast (TAF). At 11:15:00 the user looked at the wind and temperature. The user made an outgoing phone call at 13:00:10 that was a minute in duration. An incoming text that arrived at 13:53:19 was left unread.

Device 5: Samsung Galaxy Note 3 - The micro SD card located on the phone was removed and imaged using forensic software. No accident pertinent data was found.