Sunday, November 18, 2018

System / Component Malfunction / Failure (Non-Power): Rutan VariEze, N944X, accident occurred February 11, 2018 at Santa Monica Municipal Airport (KSMO), Los Angeles County, California

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

Additional Participating Entity:

Federal Aviation Administration / Flight Standards District Office; Los Angeles, California

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


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


Aviation Accident Data Summary - National Transportation Safety Board: https://app.ntsb.gov/pdf


http://registry.faa.gov/N944X

Location: Santa Monica, CA
Accident Number: WPR18LA089
Date & Time: 02/11/2018, 1258 PST
Registration: N944X
Aircraft: SHANKS V ROGER VARI EZE
Aircraft Damage: Substantial
Defining Event: Sys/Comp malf/fail (non-power)
Injuries: 2 None
Flight Conducted Under: Part 91: General Aviation - Personal

Analysis 

The private pilot reported that, during the landing roll, the experimental amateur-built airplane experienced a partial loss of right brake effectiveness. The pilot attempted to counter the directional control imbalance as the roll continued, but he became concerned that the airplane might run off the end of the runway and the drop-off at the end, so he applied maximum brake pressure. The airplane then veered left, departed the runway, and impacted a hangar.

Postaccident examination revealed that a slow fluid leak had developed at the inlet fitting of the right brake caliper, and the fluid level in the reservoir for the right brake master cylinder had dropped to just under half of its capacity. This leak most likely allowed air to be introduced into the system either through the fitting or the depleted brake reservoir, which resulted in reduced effectiveness of the right brake. Maintenance records indicated that the pilot replaced the hydraulic lines on the right side about 147 flight hours before the accident.

The airplane was equipped with a free-castering nosewheel and ground steering was accomplished through differential braking once rudder effectiveness diminished at lower speeds. Therefore, with the loss of braking effectiveness on one side, the pilot had limited means to effectively slow the airplane and maintain directional control once the airplane decelerated to a speed below which rudder authority was available.

Probable Cause and Findings

The National Transportation Safety Board determines the probable cause(s) of this accident to be:
An undetected fluid leak in the right brake line, which resulted in a reduction of braking effectiveness at the right wheel and a loss of directional control during the landing roll. 

Findings

Aircraft
Landing gear brakes system - Failure (Cause)
Landing gear steering system - Failure (Cause)
Directional control - Attain/maintain not possible (Cause)

Factual Information

History of Flight

Landing-landing roll
Sys/Comp malf/fail (non-power) (Defining event)
Runway excursion
Collision during takeoff/land 

On February 11, 2018, at 1258 Pacific standard time, an experimental amateur-built Roger V Shanks (Rutan Aircraft Factory) VariEze airplane, N944X, struck a hangar during its landing rollout at Santa Monica Municipal Airport, Santa Monica, California. The private pilot and pilot-rated passenger were not injured. The airplane sustained substantial damage to the nose and canard assembly which detached from the airframe. The airplane was registered to and operated by the pilot under the provisions of Title 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed, and no flight plan had been filed. The flight departed Brackett Field Airport, La Verne, California, about 1240.

The pilot reported that the landing approach to runway 21 was uneventful, and that he landed about 100 ft beyond the runway numbers. As soon as the nosewheel touched down, the pilot applied brake pressure and the airplane began to swerve to the left. He released and reapplied brake pressure, but the airplane continued to veer left. He then proceeded to alternately cycle the brakes and right rudder as the ground roll progressed. The oscillations continued as the airplane slowed down, but aware that the terrain dropped off beyond the runway end, the pilot decided to apply full braking effort, rather than risk descending the drop-off. The airplane then veered violently to the left, crossed over the adjacent taxiway, and struck a hangar (Photo 1).

Skid marks on the runway indicated that the airplane departed the runway surface just before taxiway B2, about 500 ft short of the runway end, and 1,300 ft before the end of the runway apron where the terrain dropped away. The skid mark on the left side was darker in color and more prominent than the mark on the right (Photo 2).


Photo 1 - Airplane in Hangar

Photo 2 - Runway Skid Marks 

Pilot Information

Certificate: Private
Age: 45, Male
Airplane Rating(s): Single-engine Land
Seat Occupied: Front
Other Aircraft Rating(s): None
Restraint Used: 4-point
Instrument Rating(s): Airplane
Second Pilot Present: Yes
Instructor Rating(s): None
Toxicology Performed: No
Medical Certification: BasicMed Without Waivers/Limitations
Last FAA Medical Exam: 07/15/2016
Occupational Pilot: No
Last Flight Review or Equivalent: 08/29/2017
Flight Time:  260 hours (Total, all aircraft), 102 hours (Total, this make and model), 179 hours (Pilot In Command, all aircraft), 9 hours (Last 90 days, all aircraft), 1 hours (Last 30 days, all aircraft), 1 hours (Last 24 hours, all aircraft)

Pilot-Rated Passenger Information

Certificate: Private
Age: 29, Male
Airplane Rating(s): Single-engine Land
Seat Occupied: Rear
Other Aircraft Rating(s): None
Restraint Used: 4-point
Instrument Rating(s): None
Second Pilot Present: Yes
Instructor Rating(s): None
Toxicology Performed: No
Medical Certification: Class 3 Without Waivers/Limitations
Last FAA Medical Exam: 12/28/2016
Occupational Pilot: No
Last Flight Review or Equivalent:
Flight Time:  (Estimated) 100 hours (Total, all aircraft), 0 hours (Total, this make and model)

Aircraft and Owner/Operator Information

Aircraft Make: SHANKS V ROGER
Registration: N944X
Model/Series: VARI EZE NO SERIES
Aircraft Category: Airplane
Year of Manufacture: 1982
Amateur Built: Yes
Airworthiness Certificate: Experimental
Serial Number: 893
Landing Gear Type: Retractable - Tricycle
Seats: 2
Date/Type of Last Inspection: 11/18/2017, Condition
Certified Max Gross Wt.: 1150 lbs
Time Since Last Inspection: 9 Hours
Engines: 1 Reciprocating
Airframe Total Time: 1536.7 Hours as of last inspection
Engine Manufacturer: CONT MOTOR
ELT: C91A installed, not activated
Engine Model/Series: O-200 SERIES
Registered Owner: On file
Rated Power: 115 hp
Operator: On file
Operating Certificate(s) Held: None 

Meteorological Information and Flight Plan

Conditions at Accident Site: Visual Conditions
Condition of Light: Day
Observation Facility, Elevation: KSMO, 174 ft msl
Distance from Accident Site: 0 Nautical Miles
Observation Time: 1302 PST
Direction from Accident Site: 34°
Lowest Cloud Condition: Clear
Visibility:  10 Miles
Lowest Ceiling: None
Visibility (RVR):
Wind Speed/Gusts: 10 knots /
Turbulence Type Forecast/Actual:
Wind Direction: 240°
Turbulence Severity Forecast/Actual:
Altimeter Setting: 29.87 inches Hg
Temperature/Dew Point: 17°C / 9°C
Precipitation and Obscuration: No Obscuration; No Precipitation
Departure Point: LA VERNE, CA (POC)
Type of Flight Plan Filed: None
Destination: Santa Monica, CA (SMO)
Type of Clearance: VFR
Departure Time: 1240 PST
Type of Airspace: Class D

Airport Information

Airport: SANTA MONICA MUNI (SMO)
Runway Surface Type: Asphalt
Airport Elevation: 169 ft
Runway Surface Condition: Dry
Runway Used: 21
IFR Approach: None
Runway Length/Width: 3500 ft / 150 ft
VFR Approach/Landing: Straight-in

The airport consisted of a single runway designated 3/21, which was shortened in December 2017 from 4,973 ft to 3,500 ft. The pilot stated that he was aware of the reduced runway length. Runway 21 slopes downhill, with a gradient of 1.2%.

Wreckage and Impact Information

Crew Injuries: 1 None
Aircraft Damage: Substantial
Passenger Injuries: 1 None
Aircraft Fire: None
Ground Injuries: N/A
Aircraft Explosion: None
Total Injuries: 2 None
Latitude, Longitude: 34.012500, -118.453889 


Photo 3 - Right Brake Caliper 

Tests And Research

Brake System

The airplane was equipped with a free-castering nosewheel, with ground steering accomplished through differential braking once rudder effectiveness diminished at lower speeds. The design did not incorporate conventional toe-brakes, but instead brake pressure was applied directly via the rudder pedals once they had been pushed beyond the pedals' rudder travel limits.

Each rudder pedal was connected via cables to combination rudder and brake bellcrank assemblies mounted on the firewall. The brake master cylinders were also mounted on the firewall and connected directly to their respective rudder bellcrank assemblies. The master cylinders contained integral reservoirs; the cylinders were the 10-35 type manufactured by Parker Corporation. Accessing the master cylinders for fluid check and service required removal of the engine cowl.

The main landing gear were equipped with conventional brake rotors and hydraulic calipers. Each wheel assembly was enclosed within a composite wheel pant, which visually obscured the caliper and brake rotor.

Postaccident examination of the brake master cylinders revealed that the right brake reservoir fluid level was filled to just under half of its capacity. Further examination revealed that the top and rear surfaces of the right caliper were coated with dirt-encrusted fluid, from a leak which appeared to have developed at the inlet fitting of the caliper (Photo 3). No active drips were observed, and examination of the remaining brake system components did not reveal any other fluid leaks or mechanical anomalies, and the left brake reservoir was full.

Maintenance records indicated that the pilot replaced the hydraulic brake lines on the right side in July 2014, 147.3 flight hours before the accident. He reported using "NylaFlow" nylon tubing, in accordance with the airframe kit manufacturers instructions, and although there was no entry in the logbooks, he also replaced the left brake lines a brief time later with the same material. He stated that the right line was replaced because a leak had developed at the fitting on the caliper, such that he found fluid on the ramp during a preflight inspection.


The pilot stated that he last checked the brake fluid reservoir levels at the most recent oil change, which according to the maintenance records, was 50.5 flight hours prior to the accident. He reported that on the morning of the accident, he had departed from two airports and tested the brakes during taxi on both occasions; the brakes performed appropriately, and no anomalies were encountered.

Collision with Hangar 

Location: Santa Monica, CA

Accident Number: WPR18LA089
Date & Time: 02/11/2018, 1258 PST
Registration: N944X
Aircraft: SHANKS V ROGER VARI EZE
Aircraft Damage: Substantial
Defining Event: Sys/Comp malf/fail (non-power)
Injuries: 2 None
Flight Conducted Under: Part 91: General Aviation - Personal

On February 11, 2018, at 1258 Pacific standard time, an experimental amateur-built Roger V Shanks (Rutan Aircraft Factory) VariEze airplane, N944X, struck a hangar during its landing rollout at Santa Monica Municipal Airport, Santa Monica, California. The private pilot and pilot-rated passenger were not injured. The airplane sustained substantial damage to the nose and canard assembly which detached from the airframe. The airplane was registered to and operated by the pilot under the provisions of Title 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed, and no flight plan had been filed. The flight departed Brackett Field Airport, La Verne, California, about 1240.

The pilot reported that the landing approach to runway 21 was uneventful, and that he landed about 100 ft beyond the runway numbers. As soon as the nosewheel touched down, the pilot applied brake pressure and the airplane began to swerve to the left. He released and reapplied brake pressure, but the airplane continued to veer left. He then proceeded to alternately cycle the brakes and right rudder as the ground roll progressed. The oscillations continued as the airplane slowed down, but aware that the terrain dropped off beyond the runway end, the pilot decided to apply full braking effort, rather than risk descending the drop-off. The airplane then veered violently to the left, crossed over the adjacent taxiway, and struck a hangar (Photo 1).

Skid marks on the runway indicated that the airplane departed the runway surface just before taxiway B2, about 500 ft short of the runway end, and 1,300 ft before the end of the runway apron where the terrain dropped away. The skid mark on the left side was darker in color and more prominent than the mark on the right (Photo 2).


Photo 1 - Airplane in Hangar

Photo 2 - Runway Skid Marks

Pilot Information

Certificate: Private
Age: 45, Male
Airplane Rating(s): Single-engine Land
Seat Occupied: Front
Other Aircraft Rating(s): None
Restraint Used: 4-point
Instrument Rating(s): Airplane
Second Pilot Present: Yes
Instructor Rating(s): None
Toxicology Performed: No
Medical Certification: BasicMed Without Waivers/Limitations
Last FAA Medical Exam: 07/15/2016
Occupational Pilot: No
Last Flight Review or Equivalent: 08/29/2017
Flight Time: 260 hours (Total, all aircraft), 102 hours (Total, this make and model), 179 hours (Pilot In Command, all aircraft), 9 hours (Last 90 days, all aircraft), 1 hours (Last 30 days, all aircraft), 1 hours (Last 24 hours, all aircraft)

Pilot-Rated Passenger Information

Certificate: Private
Age: 29, Male
Airplane Rating(s): Single-engine Land
Seat Occupied: Rear
Other Aircraft Rating(s): None
Restraint Used: 4-point
Instrument Rating(s): None
Second Pilot Present: Yes
Instructor Rating(s): None
Toxicology Performed: No
Medical Certification: Class 3 Without Waivers/Limitations
Last FAA Medical Exam: 12/28/2016
Occupational Pilot: No
Last Flight Review or Equivalent:
Flight Time:  (Estimated) 100 hours (Total, all aircraft), 0 hours (Total, this make and model)

Aircraft and Owner/Operator Information

Aircraft Make: SHANKS V ROGER
Registration: N944X
Model/Series: VARI EZE NO SERIES
Aircraft Category: Airplane
Year of Manufacture: 1982
Amateur Built: Yes
Airworthiness Certificate: Experimental
Serial Number: 893
Landing Gear Type: Retractable - Tricycle
Seats: 2
Date/Type of Last Inspection: 11/18/2017, Condition
Certified Max Gross Wt.: 1150 lbs
Time Since Last Inspection: 9 Hours
Engines: 1 Reciprocating
Airframe Total Time: 1536.7 Hours as of last inspection
Engine Manufacturer: CONT MOTOR
ELT: C91A installed, not activated
Engine Model/Series: O-200 SERIES
Registered Owner: On file
Rated Power: 115 hp
Operator: On file
Operating Certificate(s) Held: None

Meteorological Information and Flight Plan

Conditions at Accident Site: Visual Conditions
Condition of Light: Day
Observation Facility, Elevation: KSMO, 174 ft msl
Distance from Accident Site: 0 Nautical Miles
Observation Time: 1302 PST
Direction from Accident Site: 34°
Lowest Cloud Condition: Clear
Visibility: 10 Miles
Lowest Ceiling: None
Visibility (RVR):
Wind Speed/Gusts: 10 knots /
Turbulence Type Forecast/Actual: /
Wind Direction: 240°
Turbulence Severity Forecast/Actual: /
Altimeter Setting: 29.87 inches Hg
Temperature/Dew Point: 17°C / 9°C
Precipitation and Obscuration: No Obscuration; No Precipitation
Departure Point: LA VERNE, CA (POC)
Type of Flight Plan Filed: None
Destination: Santa Monica, CA (SMO)
Type of Clearance: VFR
Departure Time: 1240 PST
Type of Airspace: Class D

Airport Information

Airport: SANTA MONICA MUNI (SMO)
Runway Surface Type: Asphalt
Airport Elevation: 169 ft
Runway Surface Condition: Dry
Runway Used: 21
IFR Approach: None
Runway Length/Width: 3500 ft / 150 ft
VFR Approach/Landing: Straight-in

The airport consisted of a single runway designated 3/21, which was shortened in December 2017 from 4,973 ft to 3,500 ft. The pilot stated that he was aware of the reduced runway length. Runway 21 slopes downhill, with a gradient of 1.2%.

Wreckage and Impact Information

Crew Injuries: 1 None
Aircraft Damage: Substantial
Passenger Injuries: 1 None
Aircraft Fire: None
Ground Injuries: N/A
Aircraft Explosion: None
Total Injuries: 2 None
Latitude, Longitude: 34.012500, -118.453889


Photo 3 - Right Brake Caliper

Tests And Research

Brake System

The airplane was equipped with a free-castering nosewheel, with ground steering accomplished through differential braking once rudder effectiveness diminished at lower speeds. The design did not incorporate conventional toe-brakes, but instead brake pressure was applied directly via the rudder pedals once they had been pushed beyond the pedals' rudder travel limits.

Each rudder pedal was connected via cables to combination rudder and brake bellcrank assemblies mounted on the firewall. The brake master cylinders were also mounted on the firewall and connected directly to their respective rudder bellcrank assemblies. The master cylinders contained integral reservoirs; the cylinders were the 10-35 type manufactured by Parker Corporation. Accessing the master cylinders for fluid check and service required removal of the engine cowl.

The main landing gear were equipped with conventional brake rotors and hydraulic calipers. Each wheel assembly was enclosed within a composite wheel pant, which visually obscured the caliper and brake rotor.

Postaccident examination of the brake master cylinders revealed that the right brake reservoir fluid level was filled to just under half of its capacity. Further examination revealed that the top and rear surfaces of the right caliper were coated with dirt-encrusted fluid, from a leak which appeared to have developed at the inlet fitting of the caliper (Photo 3). No active drips were observed, and examination of the remaining brake system components did not reveal any other fluid leaks or mechanical anomalies, and the left brake reservoir was full.

Maintenance records indicated that the pilot replaced the hydraulic brake lines on the right side in July 2014, 147.3 flight hours before the accident. He reported using "NylaFlow" nylon tubing, in accordance with the airframe kit manufacturers instructions, and although there was no entry in the logbooks, he also replaced the left brake lines a brief time later with the same material. He stated that the right line was replaced because a leak had developed at the fitting on the caliper, such that he found fluid on the ramp during a preflight inspection.

The pilot stated that he last checked the brake fluid reservoir levels at the most recent oil change, which according to the maintenance records, was 50.5 flight hours prior to the accident. He reported that on the morning of the accident, he had departed from two airports and tested the brakes during taxi on both occasions; the brakes performed appropriately, and no anomalies were encountered.

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