# NTSB WPR18LA089: Shanks V Roger Vari EZE, N944X, Santa Monica, CA, February 11, 2018 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: February 11, 2018, 12:58 local (20:58 UTC) - Place: Santa Monica, CA - Coordinates: 34.0125, -118.453887 - Nearby events: https://openairdocs.org/map.md?lat=34.0125&lon=-118.4539&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Defining event: [Landing-landing roll: Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report May 29, 2019 - Report: Approved by Office Director - NTSB office: Western Pacific Region - Parties: Federal Aviation Administration FSDO - NTSB case key (mKey): 96727 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR18LA089 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/96727/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=96727 - Page: https://openairdocs.org/ntsb/WPR18LA089 ## Probable cause 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 NTSB's coded findings; those marked are part of the probable cause. - [Landing gear system: landing gear brakes system](https://openairdocs.org/ntsb-findings/01023240): Aircraft › Aircraft systems · Failure (probable cause); cases with it: [Shanks V Roger VARI-EZE, 1 case](https://openairdocs.org/ntsb-findings/01023240/cases.md?model=05609UQ), [All aircraft, 92 cases](https://openairdocs.org/ntsb-findings/01023240/cases.md) - [Landing gear system: landing gear steering system](https://openairdocs.org/ntsb-findings/01023250): Aircraft › Aircraft systems · Failure (probable cause); cases with it: [Shanks V Roger VARI-EZE, 1 case](https://openairdocs.org/ntsb-findings/01023250/cases.md?model=05609UQ), [All aircraft, 32 cases](https://openairdocs.org/ntsb-findings/01023250/cases.md) - [Performance/control parameters: directional control](https://openairdocs.org/ntsb-findings/01062020): Aircraft › Aircraft oper/perf/capability · Attain/maintain not possible (probable cause); cases with it: [Shanks V Roger VARI-EZE, 1 case](https://openairdocs.org/ntsb-findings/01062020/cases.md?model=05609UQ), [All aircraft, 3,958 cases](https://openairdocs.org/ntsb-findings/01062020/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Landing-landing roll: Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330) (defining event); cases with it: [Shanks V Roger VARI-EZE, 1 case](https://openairdocs.org/ntsb-events/330/sequence.md?model=05609UQ), [All aircraft, 994 cases](https://openairdocs.org/ntsb-events/330/sequence.md) - [Landing-landing roll: Runway excursion](https://openairdocs.org/ntsb-events/300); cases with it: [Shanks V Roger VARI-EZE, 1 case](https://openairdocs.org/ntsb-events/300/sequence.md?model=05609UQ), [All aircraft, 3,643 cases](https://openairdocs.org/ntsb-events/300/sequence.md) - [Landing-landing roll: Collision during takeoff/land](https://openairdocs.org/ntsb-events/490); cases with it: [Shanks V Roger VARI-EZE, 1 case](https://openairdocs.org/ntsb-events/490/sequence.md?model=05609UQ), [All aircraft, 1,309 cases](https://openairdocs.org/ntsb-events/490/sequence.md) ## 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. ## Factual narrative 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%. 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 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 equippedwith 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. Photo 3 - Right Brake Caliper ## Aircraft - Registration: [N944X](https://openairdocs.org/deregistered/N944X-2019-07-11), registration cancelled 2019-07-11, S/N 893, built 1982 (OpenAirDocs) - Reported make and model: SHANKS V ROGER VARI EZE (NO SERIES) - Registry model: [Shanks V Roger VARI-EZE](https://openairdocs.org/model/shanks-v-roger-vari-eze) (registry code 05609UQ) (OpenAirDocs) - Registry engine: [Continental 0-200 series](https://openairdocs.org/engine/continental-0-200-series) (registry code 17020, reciprocating) (OpenAirDocs) - Category: Airplane, amateur-built - Serial number: 893 - Year built: 1982 - Airframe hours: 1536.7 - Engines: CONT MOTOR O-200 SERIES 115 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Condition, November 18, 2017, 9 hours before - Departed: POC, LA VERNE, CA - Destination: SMO, Santa Monica, CA - Airport: SMO, Santa Monica Muni, runway 21, 3,500 × 150 ft, asphalt - Equipment: Electronic primary flight display, Electronic multifunction display ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 45; injuries: none; private; airplane ratings: single-engine land; instrument ratings: airplane; medical: basicmed, without waivers/limitations; last flight review August 29, 2017; seat: front; restraint: 4-point; flight hours: 260 total, 102 in this make and model, 179 as pilot in command, 9 in the last 90 days, 1 in the last 30 days, 1 in the last 24 hours - Pilot-rated passenger; age 29; injuries: none; private; airplane ratings: single-engine land; medical: class 3, without waivers/limitations; seat: rear; restraint: 4-point; flight hours: 100 total, 0 in this make and model ## Weather - Conditions: Visual (VMC), Day - Wind: 240° at 10 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 63 °F, dew point 48 °F - Altimeter: 29.87 inHg - Observed at: KSMO ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 20180211014499A](https://openairdocs.org/incident/20180211014499A), Feb 11, 2018: Shanks V Roger VARI-EZE, Santa Monica, CA, Substantial damage. On February 11, 2018, at 1258 pacific standard time, an experimental amateur- built roger v Shanks (rutan aircraft factory) varieze, N944X, struck a hangar… ## Docket (3 files) The files NTSB released with the investigation on October 22, 2018, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=96727. 735 KB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 476 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40467592&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Pilot Interview Summary (item 2, .PDF, 103 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40467593&FileExtension=.PDF&FileName=Pilot%20Interview%20Summary-Master.PDF - Airframe Maintenance Logbook Excerpts (item 3, .PDF, 156 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40467594&FileExtension=.PDF&FileName=Airframe%20Maintenance%20Logbook%20Excerpts-Master.PDF From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.