Sunday, September 01, 2019

Visual Flight Rules encounter with Instrument Meteorological Conditions: Cirrus SR22, N507TX; fatal accident occurred May 11, 2018 in Lone Tree, Douglas County, Colorado

Dr. Robert "Bob" Marquis, DVM, CCRT
June 14th, 1950 - May 11th, 2018

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

Additional Participating Entities: 

Federal Aviation Administration / Flight Standards District Office; Englewood, Colorado
Cirrus Aircraft; Duluth, Minnesota 
Continental Aerospace Technologies; Mobile, Alabama

Aviation Accident Final Report - National Transportation Safety Board:

Investigation Docket - National Transportation Safety Board:  

Location: Lone Tree, CO
Accident Number: CEN18FA168
Date & Time: 05/11/2018, 2019 MST
Registration: N507TX
Aircraft Damage: Destroyed
Defining Event: VFR encounter with IMC
Injuries: 1 Fatal
Flight Conducted Under: Part 91: General Aviation - Personal 


The instrument-rated private pilot departed on a visual flight rules cross-country flight just before the end of civil twilight. After departing to the north, the pilot turned onto a left downwind to depart the area toward the south; the controller advised the pilot to stay west of the extended runway centerline, which the pilot acknowledged. However, about 2 minutes after takeoff, the airplane turned east and crossed the extended centerline. After crossing the centerline, the controller asked the pilot to state his intentions, and the pilot replied that he was going to return to the airport. The airplane turned back toward the airport and began tracking west toward the extended centerline; radar contact was lost several minutes later.

The airplane impacted a field about 2.5 miles to the south of the approach end of the runway. The airplane was massively fragmented during the impact and debris was scattered for about 1,200 ft. The damage to the airplane and the ground scars at the accident site were consistent with the airplane impacting in a right wing low, nose low attitude with relatively high energy.

The postaccident examination of the engine and propeller assembly did not reveal any preimpact anomalies that would have precluded normal operation. Signatures were consistent with the engine producing power and the propeller developing thrust at the time of impact. While the massive fragmentation precluded functional testing of the flight controls, there was no damage or failure that suggested preimpact anomalies with the airframe or flight controls.

While visual meteorological conditions prevailed at the airport, statements from two pilots flying instrument approaches to runway 35R suggest that the pilot likely encountered and was flying in the clouds to the south of the airport just before the accident.

A review of radar data and voice communications revealed that the instructions issued by the controller, to the pilot, were reasonable and in accordance with air traffic control procedures. Investigators were not able to establish why the pilot did not comply with air traffic control instructions.

The accident flight was the airplane's first flight after completion of an annual inspection, and the pilot was flying to meet his family for an event in another state. It is likely that the pilot was experiencing self-induced pressure to complete the flight as planned in order to maintain the family's schedule of events, and as a result, chose to depart on the visual flight rules flight over mountainous terrain at night in marginal weather conditions. The pilot's logbook was not recovered, and the recency of his instrument flight experience could not be determined.

Based upon the reported weather conditions, the location and fragmentation of the wreckage, and radar data, it is likely that the pilot experienced spatial disorientation shortly after entering the clouds which resulted in a loss of control and descent into terrain. The reason for the pilot's stated intention to return to the airport after takeoff could not be determined, but it is possible that he became distracted and that distraction contributed to his disorientation and loss of control. 

Probable Cause and Findings

The National Transportation Safety Board determines the probable cause(s) of this accident to be:
The pilot's loss of control due to spatial disorientation. Contributing to the accident was the pilot's self-induced pressure to fly the airplane at night in marginal weather conditions. 


Performance/control parameters - Not attained/maintained (Cause)

Personnel issues
Spatial disorientation - Pilot (Cause)
Aircraft control - Pilot (Cause)
Decision making/judgment - Pilot (Factor)
Motivation/respond to pressure - Pilot (Factor)

Environmental issues
Low ceiling - Effect on operation (Cause)
Ceiling/visibility/precip - Effect on operation (Cause)

Factual Information

History of Flight

Initial climb
VFR encounter with IMC (Defining event)

Loss of control in flight

Uncontrolled descent
Collision with terr/obj (non-CFIT)

On May 11, 2018, about 2019 mountain daylight time, a Cirrus Design Corporation SR22 airplane, N507TX, impacted terrain near Lone Tree, Colorado. The private pilot was fatally injured. The airplane was destroyed. The personal flight was conducted under the provisions of Title 14 Code of Federal Regulations Part 91. Dusk, visual meteorological conditions prevailed at the airport and no Federal Aviation Administration (FAA) flight plan had been filed for the flight. The airplane had just departed from Centennial Airport (APA), Denver, Colorado, and was en route to Grand Junction Regional Airport (GJT), Grand Junction, Colorado.

According to the pilot's family, the pilot traveled to APA to pick up his airplane following the completion of an annual inspection. The pilot's family was traveling to Nevada for an event and the pilot intended to fly to GJT on the evening of the accident and then join his family in Nevada the next day.

According to FAA air traffic control transcripts, the pilot contacted the APA ground controller at 1957, and stated that he was ready to taxi, had the automatic terminal information service (ATIS) information, and was departing to the south. The pilot was cleared to taxi to runway 35R. After completing an engine run-up at the approach end of the runway, the pilot was cleared for takeoff at 2014 and was instructed by the controller to remain west of the centerline for 35R following his left downwind departure to the south; the pilot acknowledged these instructions. During this time, the pilot was issued traffic advisories for another Cirrus and a military jet trainer, both on final approach for runway 35R.

According to FAA radar data, the airplane began a left turn to the east at an altitude of about 7,100 ft mean sea level (msl) and at 2016:41 the controller instructed the pilot to "just fly east through the centerline" for traffic that was descending out of 9,000 ft. About 10 seconds later the pilot responded "fly to the east of the centerline…" The airplane continued east and crossed the extended centerline of the runway.

At 2017:28, the controller asked the pilot, "what is going to be your on course heading, what are you doing now?" About 3 seconds later, the pilot responded "…I think I'm going to return to uh return to centennial." The controller asked the pilot if he wanted to land on runway 28; the pilot did not respond. At this time the airplane was flying northeast at an altitude of 7,000 ft msl.

The airplane turned left, back towards the northwest and the extended runway centerline at an altitude of 7,000 ft msl. At 2017:57 the controller stated "remain east of the centerline for runway three five right please, I've got a Hawk descending five mile final seven thousand eight hundred indicated. I need you to remain east of the centerline." About 13 seconds later the pilot responded, "I'll stay east."

About 2018, the controller issued wind information to the pilot and asked if he would like runway 28 or runway 35R. About 38 seconds later the pilot responded, "…give me the winds one more time." The controller then stated "… you're still flying westbound, please, I need you east, east of the centerline, please remain east of the centerline." The pilot did not respond. The airplane was about 7,700 ft msl and flying west-northwest.

At 2019:05 the controller stated "…I need you to do what I'm telling you to do, now fly westbound, continue westbound." The pilot did not respond, and radar contact was lost about 2019. 

Dr. Robert "Bob" Marquis

Pilot Information

Certificate: Private
Age: 67, Male
Airplane Rating(s): Single-engine Land
Seat Occupied: Left
Other Aircraft Rating(s): None
Restraint Used: Unknown
Instrument Rating(s): Airplane
Second Pilot Present: No
Instructor Rating(s): None
Toxicology Performed:Yes 
Medical Certification: Class 2 Without Waivers/Limitations
Last FAA Medical Exam: 05/20/2016
Occupational Pilot: No
Last Flight Review or Equivalent:
Flight Time:  (Estimated) 2300 hours (Total, all aircraft), 575 hours (Total, this make and model) 

The pilot's flight logbook was not located during the investigation and his total flight time or recent experience could not be determined. According to the pilot's last medical certificate application, dated May 19, 2016, he estimated his total flight time as 2,300 hours. 

Aircraft and Owner/Operator Information

Registration: N507TX
Model/Series: SR22
Aircraft Category: Airplane
Year of Manufacture:
Amateur Built: No
Airworthiness Certificate: Normal
Serial Number: 1429
Landing Gear Type: Tricycle
Seats: 4
Date/Type of Last Inspection: 05/11/2018, Annual
Certified Max Gross Wt.: 3400 lbs
Time Since Last Inspection: 1 Hours
Engines: 1 Reciprocating
Airframe Total Time: 1269 Hours at time of accident
Engine Manufacturer: Teledyne Continental Motors
ELT: Installed
Engine Model/Series: IO-550-N (27)
Registered Owner: On file
Rated Power: 310 hp
Operator: On file
Operating Certificate(s) Held: None 

In April 2018, the pilot took the airplane to APA for its annual inspection. The annual maintenance was completed on May 11, 2018, and the accident flight was the first flight following the annual maintenance. According to maintenance personnel, the inspection and maintenance was routine. The owner of the maintenance facility stated that in 2013, the Avidyne primary flight display (PFD) altimeter had failed the 14 CFR 91.411 test and was about 10 to 15 ft beyond the allowable tolerances. The pilot had deferred maintenance on the unit in 2013 and every year since, as this maintenance would require the entire unit to be removed and returned to the manufacturer.

Meteorological Information and Flight Plan

Conditions at Accident Site: Visual Conditions
Condition of Light: Night/Dark
Observation Facility, Elevation: KAPA, 5869 ft msl
Distance from Accident Site: 2 Nautical Miles
Observation Time: 1953 MDT
Direction from Accident Site: 360°
Lowest Cloud Condition:
Visibility:  7 Miles
Lowest Ceiling: Broken / 1500 ft agl
Visibility (RVR):
Wind Speed/Gusts: 14 knots / 21 knots
Turbulence Type Forecast/Actual: / None
Wind Direction: 350°
Turbulence Severity Forecast/Actual: / N/A
Altimeter Setting: 29.87 inches Hg
Temperature/Dew Point: 15°C / 12°C
Precipitation and Obscuration: No Obscuration; No Precipitation
Departure Point: Denver, CO (KAPA)
Type of Flight Plan Filed: None
Destination: Grand Junction, CO (KGJT)
Type of Clearance: VFR
Departure Time: 2011 MDT
Type of Airspace: Class D 

The closest official weather observation station was at APA, located 2.5 nautical miles (nm) north-northwest of the accident site. The elevation of the weather observation station was 5,885 ft msl. The routine aviation weather report (METAR) for APA, issued at 1953, reported, wind 350° at 14 knots, gusting to 21 knots, 7 miles visibility, sky condition, 1,500 ft broken, 10,000 ft overcast, temperature 15° Celsius (C), dew point temperature 12° C, and an altimeter of 29.82 inches of mercury. The pilot of another airplane, who was flying the instrument landing system approach to runway 35R, reported breaking out of the clouds at 6,800 ft msl.

Two different pilots on instrument approach to runway 35R at APA, about the time of the accident, reported broken-to-overcast skies between 800 ft and 1,000 ft agl, with ragged cloud bottoms, no turbulence, no icing, and no precipitation. A witness walking in a subdivision just to the east of the accident location reported low clouds, about 200 ft overcast with surface winds in excess of 25 knots.

A security camera mounted on the APA air traffic control tower and facing south captured a light, likely from the accident airplane, just before the accident. The surveillance camera image, taken from the camera mounted on the catwalk of the air traffic control tower, showed dusk lighting conditions and a potential lower cloud layer to the south where the accident occurred. The light from the airplane was not visible above the horizon until the first image captured at 2018:40. The images taken 2 seconds before and 2 seconds after did not show any lights in that direction.

According to the United States Naval Observatory, Astronomical Applications Department Sun and Moon Data, sunset was recorded at 2005 and the end of civil twilight was recorded at 2035.

A search of official weather briefing sources, such as contract Automated Flight Service Station (AFSS) provider Leidos weather briefings and the Direct User Access Terminal Service (DUATS), revealed that the accident pilot did not request a weather briefing through either source.

According to a witness who spoke with the pilot just before the accident flight, the pilot was concerned about the weather in the area and was planning to fly south to avoid the weather.

Airport Information

Airport: Centennial Airport (APA)
Runway Surface Type: Asphalt
Airport Elevation: 5885 ft
Runway Surface Condition: Dry
Runway Used: 35R
IFR Approach: None
Runway Length/Width: 10000 ft / 100 ft
VFR Approach/Landing: 

Centennial Airport is a public, controlled airport (class D) located 15 miles southeast of Denver, Colorado, at a surveyed elevation of 5,885 ft. The airport had three open runways; 17L/35R, 17R/35L, and 10/28. The class D airspace extended upward from the surface to 8,000 ft msl and within a 4.4-mile radius. The class D airspace was surrounded by class E airspace.

Wreckage and Impact Information

Crew Injuries: 1 Fatal
Aircraft Damage: Destroyed
Passenger Injuries: N/A
Aircraft Fire: None
Ground Injuries: N/A
Aircraft Explosion: None
Total Injuries: 1 Fatal
Latitude, Longitude: 39.516111, -104.833889 

The airplane impacted an open field 2.5 miles south-southwest of the approach end of runway 35R and just west of a housing development. Witness marks at the initial impact point were consistent with a right wing-low, nose-level attitude at the time of impact. The airplane was fragmented, and debris was scattered for 1,219 ft.

The initial impact point was characterized by a long narrow ground scar that contained paint chips consistent with the wing of the airplane. The ground scar continued 12 ft east to three ground scars consistent in size and location with the nose and the main landing gear. The ground scar widened and contained paint chips and debris consistent with the fuselage of the airplane for another 40 ft. The far edge of the ground scar contained witness marks consistent with propeller strikes.

A debris field continued from the initial impact point, to the east, for 1,100 ft. Fragmented pieces of both wings, the empennage, and the fuselage, were contained within the debris field. The debris field also contained components of the engine exhaust system, the fragmented instrument panel, and various personal effects.

The engine separated from the fuselage and propeller assembly and came to rest at the easternmost side of the debris field. The engine was imbedded in the west-facing side of the wall of a home.

The cockpit instruments separated from their cockpit locations, were fragmented, and did not convey reliable readings.

The scope of the airframe, engine, and systems examination was limited by fragmentation due to impact damage; however, no anomalies consistent with a preimpact failure or malfunction were observed.

The details of the wreckage examination are available in the public docket for this investigation. 

Flight Recorders

The accident airplane was equipped with an Avidyne PFD and an Avidyne multi-function display (MFD). The PFD and flash memory device from the MFD were sent to the NTSB Vehicle Recorders Lab in Washington, D.C., for download. The PFD recording contained a record consistent with the accident flight that was 25 minutes and 56 seconds in duration. The MFD contained a data file that was 25 minutes and 6 seconds in duration.

The engine parameter data recovered from the PFD and MFD, to include the cylinder head temperatures, exhaust gas temperatures, manifold pressure, oil pressure, and fuel flow, were consistent with normal operating ranges. A spike in these parameters at 2009 was consistent with an engine runup before takeoff and the increase about 2013 was consistent with takeoff.

Pitch and roll data obtained from the unit was consistent with the radar data. The recorded roll parameter indicated that the airplane banked greater than 30° to the right and left several times during the last 2 minutes of the accident flight.

Additional details and information related to the data recovered are contained in the specialist's factual report available in the public docket for this investigation.

Medical And Pathological Information

The Douglas County Coroner's Office, Castle Rock, Colorado, performed the autopsy on the pilot on May 12, 2018. The autopsy concluded that the cause of death was "multiple blunt force injuries" and the report listed the specific injuries.

The FAA Forensic Sciences Laboratory, Oklahoma City, Oklahoma, performed toxicological tests on specimens that were collected during the autopsy. Results were negative for ethanol. Testing of the muscle and liver tissue revealed trace amounts of pseudoephedrine. Carbon Monoxide and cyanide tests were not performed.

According to the FAA Aerospace Medical Research website, pseudoephedrine is a common over the counter decongestant used in the treatment of the common cold and hay fever. The medication found during the pilot's toxicological testing does not cause impairment or incapacitation.

Additional Information

Air Traffic Control Services

According to FAA JP 7110.65X, "Air Traffic Control", the primary purpose of the air traffic control (ATC) system is to prevent a collision involving aircraft operating in the system. In addition, the ATC system provides a safe, orderly, and expeditious flow of traffic."

Title 14 CFR Part 91.123 states in part that "Except in an emergency, no person may operate an aircraft contrary to an ATC instruction in an area in which air traffic control is exercised.

The details to the Air Traffic Control Specialists factual report are contained in the public docket for this investigation.

Spatial Disorientation

The FAA Civil Aeromedical Institute's publication, "Introduction to Aviation Physiology," defines spatial disorientation as a loss of proper bearings or a state of mental confusion as to position, location, or movement relative to the position of the earth. Factors contributing to spatial disorientation include changes in acceleration, flight in IMC, frequent transfer between visual meteorological conditions (VMC) and IMC, and unperceived changes in aircraft attitude.

The FAA's Airplane Flying Handbook (FAA-H-8083-3A) describes some hazards associated with flying when the ground or horizon are obscured. The handbook states, in part: 

The vestibular sense (motion sensing by the inner ear) in particular tends to confuse the pilot. Because of inertia, the sensory areas of the inner ear cannot detect slight changes in the attitude of the airplane, nor can they accurately sense attitude changes that occur at a uniform rate over a period of time. On the other hand, false sensations are often generated; leading the pilot to believe the attitude of the airplane has changed when in fact, it has not. These false sensations result in the pilot experiencing spatial disorientation.


  1. sad story. I'm not understanding the IMC, but from the radio calls he certainly sounded like he was struggling with spatial disorientation. Wonder why he didn't slow down and pull the chute? With 575+ hours "in type" you'd think he'd be conversant with the system.

    I see yet again a very experienced pilot (>2300 hours) and accomplished individual without an instrument ticket. What's up with that?

  2. apparently couldn't operate the a/p either.

  3. He’s in IMC that’s why he’s disoriented. Two other airplane report breaking out about 6,800 and he had claimed to 7,000.

  4. Maybe if he had declared an emergency, the controller could have given him vectors back to the airport instead of yelling at him to stay to the east of centerline. And yes, he should have pulled the chute and saved himself. Sad story that happens all to often.

  5. Instrument rating should be required all pilots.

  6. By his communications with the controller the pilot seemed very preoccupied with something. The assumption here was he was having difficulty flying in IMC but with a airplane coming out of annual there could have been a host of issues that might have popped up. Being instrument rated the weather by itself should not have been a issue. His biggest mistake was attempting a flight in a aircraft that had just completed a inspection in marginal weather at night. The combination of all three factors along with a desire to meet family obligations completed this accident chain.

  7. Agreed, something was distracting him from flying the airplane. He should have made a "test" flight in day VFR conditions just to check things out before launching into more demanding conditions. This is why I read this blog, just to learn from others mistakes and hopefully not end up on here myself.

  8. Apparently he did not realize he was disoriented. If he was instrument rated, it is strange that he lost it. Could be that the instruments after the maintenance were giving him the false impression he had it under control when he did not. His request to return indicates he believed something was wrong enough to get back on the ground. He was telling the controller he was where he was supposed to be but the controller is telling him he is not. He just didn't know it was so wrong that it warranted pulling the chute and scraping the airplane. I'm sure that if he knew what we know he'd pulled the chute no problem. He just didn't know that he had to pull it to live. Controller was not on the ball. Instead of lecturing the pilot, the controller could have inquired about what the pilot was seeing on the panel because the aircraft was not responding correctly. This could have alerted the pilot about the seriousness of the situation.

    FAA is running seminars now on how to check out your plane after maintenance. Too late for this pilot. RIP doc.

    (The A&P who did my condition inspection last year totally blew major issues such as oil in the PSRU!). You can't trust any A&P to do the job right. Check it yourself in a way that does not endanger you!).

  9. "He needed to climb, confess, and comply... really that’s it. If it was a typical SR22 and everything was working, the autopilot could have taken him up and brought him back down if he knew how to use it."

    The Avidyne primary flight display (PFD) offers a big artificial horizon on top with an airspeed tape on the left and an altimeter tape on the right. Underneath is a horizontal situation indicator (HSI) with a turn rate indicator. All of the functions of an air data computer are built in so you get a continuous readout of true air speed, ground speed, and a wind vector labeled with magnetic direction and velocity. The HSI displays a simplified moving map of the flight plan and waypoints within and around the compass rose of the HSI.
    What the Avidyne MFD Does
    The Avidyne multi-function display (MFD) shows a moving map with some terrain and Victor airway information, but very little detail on roads, bodies of water, towns, and other ground features. Depending on what options you've paid for, the MFD can also show weather, traffic, and engine data.
    What the Avidyne system does not do
    The Avidyne system does not include a GPS or any other method of navigation. The Avidyne units rely on data feeds from external GPS and Nav radio receivers. The Avidyne system does not include an autopilot, though the PFD can function as the altitude preselect panel of an autopilot system, at the cost in the Cirrus SR20 and SR22 of losing the altitude deviation alert function. The Avidyne system does not include any communication radios.


  10. ^^ It's actually, 'communicate, confess and comply' ^^