Saturday, September 08, 2018

Aerodynamic Stall/Spin: Cessna 170, N4244V; fatal accident occurred April 15, 2017 at Williston Municipal Airport (X60), Levy County, Florida

On Easter Sunday April 15th, 2017 Nate Enders, his beautiful wife Laura, and 2 of their sons Jaden and Eli died doing what they loved doing when their plane crashed at Williston Municipal Airport (X60), Florida.













Aviation Accident Final Report - National Transportation Safety Board

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

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

Investigation Docket - National Transportation Safety Board:

Location: Williston, Florida
Accident Number: ERA17FA155
Date and Time: April 15, 2017, 15:23 Local
Registration: N4244V
Aircraft: Cessna 170
Aircraft Damage: Destroyed
Defining Event: Aerodynamic stall/spin
Injuries: 4 Fatal
Flight Conducted Under: Part 91: General aviation - Personal

Analysis

***This report was modified on October 15, 2018. Please see the docket for this accident to view the original report.***

The commercial pilot and three passengers were making a personal cross-country flight in the airplane. After a refueling stop, the airplane taxied to the runway and departed. Security video and flight data showed that the airplane had just departed the airport and was about 280 ft above the ground when it stalled and spun to the left, impacting the ground in a nose-down attitude. Post-accident examination of the engine and airframe revealed no evidence of a mechanical anomaly or failure that would have precluded normal operation of the airplane. The recorded weather at the airport at the time of the accident included a right-quartering headwind at 8 knots gusting to 17 knots. The flight data revealed that the airplane slowed to an estimated airspeed (ground speed with correction applied for reported wind conditions) of around 49 to 51 knots just before the stall occurred, which was near the airplane's published power-on stall speed of 46 knots; however, the gusting wind conditions likely resulted in a further decrease of the airplane's airspeed and increase of its angle-of-attack.

Probable Cause and Findings

The National Transportation Safety Board determines the probable cause(s) of this accident to be:
The pilot's failure to maintain adequate airspeed during initial climb in gusty wind conditions, which resulted in the airplane exceeding its critical angle-of-attack and experiencing an aerodynamic stall/spin.

Findings

Personnel issues Aircraft control - Pilot
Aircraft Airspeed - Not attained/maintained
Aircraft Angle of attack - Not attained/maintained
Environmental issues Gusts - Effect on operation

Factual Information

History of Flight

Initial climb Aerodynamic stall/spin (Defining event)
Uncontrolled descent Collision with terr/obj (non-CFIT)

On April 15, 2017, about 1523 eastern daylight time, a Cessna 170, N4244V, was destroyed when it impacted terrain shortly after departure from Williston Municipal Airport (X60), Williston, Florida. The commercial pilot and three passengers were fatally injured. The airplane was owned and operated by the pilot in accordance with the provisions of Title 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed, and no flight plan was filed for the personal cross-country flight that was destined for Inverness Airport (INF), Inverness, Florida.

According to a Federal Aviation Administration (FAA) inspector, earlier on the day of the accident, the airplane departed from its base at Eagles Landing Airport (5GA3), Williamson, Georgia. Fueling records showed that the airplane stopped at Thomaston-Upson County Airport (OPN), Thomaston, Georgia, and was fueled there at 1131. The airplane then flew from OPN to X60, and an airport security video showed the airplane being fueled at X60 about 1448. The video then showed the airplane as it taxied onto runway 5 at intersection C and took off.

Video from another security camera at X60 showed the airplane immediately after takeoff as it climbed to about 280 ft above ground level and leveled off. The video then showed the airplane make a slight right turn followed by a sharp left turn and a steep descent as it rolled to an inverted position.

Flight data was downloaded from a Stratus ADS-B receiver that was recovered from the airplane and forwarded to the NTSB Vehicle Records Laboratory, Washington, DC. Review of the downloaded data revealed that the airplane's ground speed was about 47 knots just before it began to roll to the right.

Pilot Information

Certificate: Commercial; Flight instructor 
Age: 37, Male
Airplane Rating(s): Single-engine land; Multi-engine land
Seat Occupied: Left
Other Aircraft Rating(s): Glider 
Restraint Used: Lap only
Instrument Rating(s): Airplane 
Second Pilot Present: No
Instructor Rating(s): Airplane multi-engine; Airplane single-engine
Toxicology Performed: Yes
Medical Certification: Class 2 Without waivers/limitations
Last FAA Medical Exam: March 27, 2017
Occupational Pilot: No 
Last Flight Review or Equivalent:
Flight Time: (Estimated) 2350 hours (Total, all aircraft)

According to FAA records, the pilot held a commercial pilot certificate with ratings for airplane single-engine land, airplane multi-engine land, glider, and instrument airplane. He held a flight instructor certificate with ratings for airplane single-engine, airplane multi-engine, and instrument airplane. He held an FAA second-class medical certificate, issued March 27, 2017.

At the time of the medical examination for this medical certificate, the pilot reported 2,350 total hours of flight experience. The pilot's current logbooks could not be located.

Aircraft and Owner/Operator Information

Aircraft Make: Cessna 
Registration: N4244V
Model/Series: 170 UNDESIGNATED
Aircraft Category: Airplane
Year of Manufacture: 1948 
Amateur Built:
Airworthiness Certificate: Normal
Serial Number: 18600
Landing Gear Type: 
Tailwheel Seats: 4
Date/Type of Last Inspection: June 3, 2016 Annual
Certified Max Gross Wt.: 2200 lbs
Time Since Last Inspection: 46 Hrs
Engines: 1 Reciprocating
Airframe Total Time: 3657.4 Hrs at time of accident
Engine Manufacturer: CONT MOTOR
ELT: C91 installed, activated, aided in locating accident
Engine Model/Series: C145-2H
Registered Owner:
Rated Power: 145 Horsepower
Operator: On file
Operating Certificate(s) Held: None

The four-seat, high-wing, tailwheel-equipped airplane was manufactured in 1948. It was powered by a 145-horsepower Continental C-145-2H engine and equipped with a two-blade McCauley propeller. The last annual inspection was completed on June 3, 2016. At the time of the accident, the airframe and engine each had a total time of 3,657.4 hours and 46 hours since the annual inspection. The engine had
194.3 hours since major overhaul.

The airplane owner's manual stated that the power-on stall speed with no flaps was 53 mph (46 knots).

Meteorological Information and Flight Plan

Conditions at Accident Site: Visual (VMC)
Condition of Light: Day
Observation Facility, Elevation: X60,76 ft msl 
Distance from Accident Site:
Observation Time: 15:19 Local
Direction from Accident Site:
Lowest Cloud Condition: Scattered
Visibility: 10 miles
Lowest Ceiling: None
Visibility (RVR):
Wind Speed/Gusts: 8 knots / 17 knots
Turbulence Type Forecast/Actual:  / None
Wind Direction: 80° 
Turbulence Severity Forecast/Actual:  / N/A
Altimeter Setting: 30.22 inches Hg
Temperature/Dew Point: 30°C / 14°C
Precipitation and Obscuration: No Obscuration; No Precipitation
Departure Point: Williston, FL (X60 )
Type of Flight Plan Filed: None
Destination: INVERNESS, FL (INF)
Type of Clearance: None
Departure Time: 15:23 Local
Type of Airspace: Class G

At 1519, the recorded weather at X60 was wind from 080°; at 8 knots gusting to 17 knots, visibility 10 statute miles, temperature 30°C, dew point temperature 14°C, and altimeter 30.23 inches of mercury.

Airport Information

Airport: WILLISTON MUNI X60
Runway Surface Type: Concrete
Airport Elevation: 75 ft msl
Runway Surface Condition: Dry
Runway Used: 5 
IFR Approach: None
Runway Length/Width: 6999 ft / 100 ft 
VFR Approach/Landing: None

Wreckage and Impact Information

Crew Injuries: 1 Fatal 
Aircraft Damage: Destroyed
Passenger Injuries: 3 Fatal 
Aircraft Fire: None
Ground Injuries: N/A
Aircraft Explosion: None
Total Injuries: 4 Fatal 
Latitude, Longitude: 29.366111,-82.463607(est)

The wreckage was examined at the accident site, which was located near the departure end of runway 5 about 543 ft left of the runway's centerline. The airplane was resting on its nose and displayed signatures consistent with a nose-down attitude at ground impact. The wing leading edges were crushed aft by impact forces, and the engine was buried about 2 ft in the dirt. The fuselage was crushed (accordioned) aft by impact forces. The airplane came to rest on a magnetic heading of about 050°.

The left-wing fabric was torn in several places. The fuel cap separated and was found next to the airplane. Aviation 100LL fuel was noted in the left tank, which appeared to be full of fuel. The left aileron and flap remained attached and intact.

The right wing exhibited more severe leading-edge damage than the left wing. The leading edge was crushed by impact forces, and the fabric was torn in several places. The two fuel tanks in the right wing contained aviation 100LL fuel. The right fuel cap had separated and was found next to the airplane. The right flap and the aileron remained attached and intact.

The tail of the airplane did not contact the ground; the rudder and elevator were intact and not damaged. Flight control continuity was confirmed to all primary flight controls. The elevator trim was in the neutral position. The cockpit was destroyed.

The propeller remained attached to the engine. The propeller blades were bent aft. The engine and propeller were pushed into the instrument panel and upwards at a 45° angle.

The engine remained attached to the airframe by the right rear engine mount only. The other three engine mounts were fractured by impact forces. The engine case was impact damaged, and several pieces of the case were fractured and missing in the front of the engine. All six cylinders remained attached to the engine case and displayed varying amounts of impact damage. Valve train continuity was established through the engine by visual confirmation during an engine teardown. There were no preimpact anomalies noted during the teardown that would have prevented normal engine operation or production of rated horsepower.

Medical and Pathological Information

The Office of the Medical Examiner, Gainesville, Florida, performed an autopsy of the pilot, and his cause of death was injuries sustained in the accident.

The FAA Bioaeronautical Sciences Research Laboratory, Oklahoma City, Oklahoma performed forensic toxicology testing of specimens from the pilot; The tests were negative for carbon monoxide, drugs, and alcohol.


Video: Listen to Nate Enders at work as a TRACON controller.

Nate Enders began his Federal Aviation Administration career as a certified professional controller at New York TRACON. Shortly after, Nate became a certified professional controller at Dallas TRACON and most recently became certified at Atlanta TRACON. 




Nate Enders

17 comments:

  1. Flying your family around in an antique. How very very sad.

    ReplyDelete
    Replies
    1. really? how so? I fly my family around in a 49 year old AA1 without thought.

      Delete
  2. It being an "antique" is not indicative of airworthiness.
    Agree that weight and balance should have been evaluated. Odd no mention of it.
    It is also curious that the summary of wreckage analysis does not mention whether there was a stall warning horn installed in the plane and if so, whether the stall warning was operational.

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  3. Hard to believe that such a simple but deadly mistake could've been made by such an experienced (2300+ hours) pilot...sounds more like a seat stop failure...

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    Replies
    1. Correctly stated, that would not be a seat stop failure, but a maintenance failure. Do you blame and out of fuel condition on the fuel, or the person who ran the airplane out of fuel?

      Delete
  4. I flew with Nate, very experienced and intelligent pilot. He worked crash investigations for the NTSB and I helped him with his aircraft purchases over the years as an IA, ATP, etc. Seat stops would have been identified in the post accident investigation, so that is not it. Wind gusts were 8 gusting to 17, that is a 200% gust factor! And that is just the reported gusts. With a high gust factor off the right nose, it fits the witness reports, turn to the right (gust from 80 deg) which would have resulted in a higher angle of attack on the left wing which then stalled and spun to the left. Stall warning would have not helped.

    I miss my friend terribly.

    ReplyDelete
    Replies
    1. I'm very sorry for the loss of your friend and his family.

      Your scenario seems likely. Additionally, if you are at a high angle of attack and your left wing drops, if you try to instinctively turn the yoke to the right to raise that dropped wing, all that will do is lower your left aileron and push that dropped wing past the critical angle of attack and cause it to drop even more due to an aileron stall. The more you try to use aileron to lift the dropped wing, the more it will stall that wing and will quickly cause a spin. At high angles of attack, you must use rudder to lift a dropped wing. This is a skill that should be practiced frequently so your muscle memory of using aileron to pick up a dropped wing is broken. Unfortunately, even experienced pilots don't often practice aileron stall recovery.

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  5. As noted, wind from 080° at 8 knots gusting to 17 knots as PIC departed Rwy 5 from X60 (29°21'17"N 82°28'14"W) to INF (28°48'13"N 82°19'06"W), direct route of 166°, destination 39 mi.
    The C-170s 145-horsepower Continental C-145-2H engine and equipped with a two-blade McCauley propeller was not enough with a full load of fuel and paxs.

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  6. beautiful family , in the air same as on water give it a chance and it will take you

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  7. That c-145 isn't a strong performer with 6 cylinders. I don't know, but would guess that the climb rate of the 170 with 4 people and near full of fuel is probably negative on 5 cylinders.
    The 'valve train continuity established' and 'no defects noted during teardown that would prevent rated power' don't address the possibility of a sticking valve causing an intermittent dead cylinder (even more than one). This sort of failure is temperature related, and usually first shows up when run at high power for some time..i.e. takeoff and climb. It could "fix itself" under all other conditions.
    I see a lot of tall trees around the departure end of that runway. A descent into them after a power loss wouldn't be very appealing, especially with family on board. The thought of losing that sharp looking 170 wouldn't be, either, if that secondary consideration entered his thoughts...
    Maybe that happened and he thought he'd be able to nurse it around right at Vs, make it back. I wish he were right. If this is what happened, it might have been a matter of a knot or two, one gust, or the tailwind/loss of airspeed caused by turning away from any headwind he took off into..
    American flight 191 died by a few knots, also.

    Another valvetrain problem that would go probably undetected during this teardown would be incorrect dry tappet clearance, which seems to be largely dismissed by many A/P's when changing a cylinder. Reconditioning of old cylinders usually means cutting valve seats, reducing this important clearance. Some well used/REused cylinders were likely on this 70 year old 3600 hour engine. This problem would probably be less dramatic than the roughness that can go with, say, an exhaust valve sticking full open, and the total loss of 1 cyl. that would result. But it is still a power loss, and this takeoff may have depended on having all 145 hp.
    The last annual was 10 months/46 hrs earlier.

    ReplyDelete
    Replies
    1. I like your analysis. Something seems not-quite-right here for someone with this experience and ratings level plus living the aviation environment as a career every day and seeing everyone else's mistakes. Maybe it's as simple as unexpected low performance with gusts plus a power issue or something, but whatever it was, we need to learn from it. Maintaining safe margins really matters; AQP-type training matters, with a loaded airplane so that the scenarios and responses to them are felt, experienced, and well-practiced.

      Delete
    2. I forgot carb ice as a possibility, also. Another thing worth mentioning that "no defects noted during teardown" just doesn't cover.
      I say that without knowing the weather conditions, but...Florida, April....could be.

      Delete
  8. I never pack anybody on a motorcycle for fear of getting them hurt. I have flown every family member at one time or another without much thought to the possibilities.

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  9. Jaden Enders was my first friend 7 years ago, he was in 1st grade I was in 2nd. I remember we played together on the playground everyday in 2017. I’m now in 9th grade wish I could have seen him grow up. I remember everyone told me he died and I didn’t believe everyone and the counselors came and took me to an empty room. And told me what happened and then I started to cry and cry because I had lost my best friend. This was all so long ago now. -RT

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