# NTSB WPR17LA165: Lake LA 4, N7628L, Byron, CA, July 25, 2017 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 3 · Limited · Final report - Date: July 25, 2017, 13:10 local (20:10 UTC) - Place: Byron, CA - Coordinates: 37.826667, -121.62305 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=37.8267&lon=-121.6231&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Defining event: [Landing-flare/touchdown: Landing gear collapse](https://openairdocs.org/ntsb-events/094) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Western Pacific Region - Parties: FAA-FSDO - NTSB case key (mKey): 95662 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR17LA165 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/95662/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=95662 - Page: https://openairdocs.org/ntsb/WPR17LA165 ## Probable cause The pilot’s failure to activate the hydraulic system during the approach, and his failure to ensure that the landing gear was down and locked before touchdown. Contributing to the accident was the pilot's decision to operate the airplane with an inoperative landing gear position indicator light. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Hydraulic power system: hydraulic, main system](https://openairdocs.org/ntsb-findings/01022910): Aircraft › Aircraft systems · Incorrect use/operation (probable cause); cases with it: [Lake LA-4, 1 case](https://openairdocs.org/ntsb-findings/01022910/cases.md?model=5110302), [All aircraft, 27 cases](https://openairdocs.org/ntsb-findings/01022910/cases.md) - [Landing gear system: gear position and warning](https://openairdocs.org/ntsb-findings/01023260): Aircraft › Aircraft systems · Not serviced/maintained (probable cause); cases with it: [Lake LA-4, 1 case](https://openairdocs.org/ntsb-findings/01023260/cases.md?model=5110302), [All aircraft, 37 cases](https://openairdocs.org/ntsb-findings/01023260/cases.md) - [Use of equip/info: use of equip/system](https://openairdocs.org/ntsb-findings/02063015): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Lake LA-4, 1 case](https://openairdocs.org/ntsb-findings/02063015/cases.md?model=5110302), [All aircraft, 1,391 cases](https://openairdocs.org/ntsb-findings/02063015/cases.md) - [Info processing/decision: decision making/judgment](https://openairdocs.org/ntsb-findings/02041520): Personnel issues › Action/decision · Pilot (probable cause); cases with it: [Lake LA-4, 1 case](https://openairdocs.org/ntsb-findings/02041520/cases.md?model=5110302), [All aircraft, 3,098 cases](https://openairdocs.org/ntsb-findings/02041520/cases.md) - [Landing gear system](https://openairdocs.org/ntsb-findings/01023200): Aircraft › Aircraft systems · Incorrect use/operation (probable cause); cases with it: [Lake LA-4, 1 case](https://openairdocs.org/ntsb-findings/01023200/cases.md?model=5110302), [All aircraft, 113 cases](https://openairdocs.org/ntsb-findings/01023200/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Landing-flare/touchdown: Landing gear collapse](https://openairdocs.org/ntsb-events/094) (defining event); cases with it: [Lake LA-4, 1 case](https://openairdocs.org/ntsb-events/094/sequence.md?model=5110302), [All aircraft, 1,787 cases](https://openairdocs.org/ntsb-events/094/sequence.md) - [Landing-landing roll: Runway excursion](https://openairdocs.org/ntsb-events/300); cases with it: [Lake LA-4, 1 case](https://openairdocs.org/ntsb-events/300/sequence.md?model=5110302), [All aircraft, 3,643 cases](https://openairdocs.org/ntsb-events/300/sequence.md) ## Analysis During landing, the nose landing gear and right main landing gear collapsed, and the airplane veered off the runway. The pilot stated that it was likely that he switched the hydraulic pump off during the accident flight. Although both the hydraulic switch position and checking the hydraulic system pressure were included in his before-landing checklist, he could not recall their position and indication, respectively, during the accident approach. The pilot also reported that he had been experiencing issues with the landing gear microswitches, and the airplane's landing gear indicator light was inoperative as a result. Postaccident examination of the airplane and landing gear system revealed no evidence of mechanical malfunctions or anomalies that would have precluded normal operation. It is likely that the pilot's failure to properly configure the hydraulic switch, and his subsequent failure to recognize the error during his before-landing check, resulted in inadequate hydraulic pressure to extend and lock the landing gear. The airplane's inoperative landing gear indicator light likely contributed to the pilot's failure to recognize that the landing gear was not fully extended and locked before landing. ## Factual narrative On June 25, 2017, about 1310 Pacific daylight time, a Lake LA-4 airplane, N7628L, was substantially damaged when it was involved in an accident near Byron, California. The pilot and passenger were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported that, during the approach for landing, he positioned the flaps to the fully extended position. Once established on the approach, he “performed his pre-landing checks, including visual inspection of the landing gear, which looked normal.” The airplane landed normally, and he could feel all three wheels on the ground. Subsequently, the airplane began to sink to the right, followed by a right yaw, then it veered off the right side of the runway. A postaccident examination of the airplane revealed that the nose landing gear and the right landing gear collapsed, and the keel was substantially damaged. The pilot reported that he had experienced issues with the landing gear microswitches failing to close properly on previous flights, which meant that the landing gear down indicator light would not illuminate., Thus, he had to visually confirm that the landing gear was down. He stated that both main landing gear were visible from the cockpit and the nose landing gear was visible from a mirror positioned on the left sponson. The pilot stated that adjustments were made to the microswitches after those flights but that he continued to conduct landings without the landing gear down indicator light being illuminated. He further stated that, for the accident flight, it was most likely that he switched the hydraulic pump off during the flight and didn’t notice the position of the switch or the indicated low hydraulic system pressure during the approach. He stated that both the hydraulic switch position and checking the hydraulic system pressure were part of his before-landing checklist, but he could not recall their position and indication, respectively, during the accident approach. Following the accident, after the airplane was lifted, the right main landing gear was pushed by hand into its down-and-locked position. The nose landing gear locked into position after activating the emergency gear extension pump. There was no evidence of preexisting malfunctions or failures that would have precluded normal operation of the airplane. ## Aircraft - Registration: [N7628L](https://openairdocs.org/aircraft/N7628L), registered now, S/N 401, built 1969 (OpenAirDocs) - Reported make and model: LAKE LA 4 (UNDESIGNAT) - Registry model: [Lake LA-4](https://openairdocs.org/model/lake-la-4) (registry code 5110302) (OpenAirDocs) - Registry engine: [Lycoming O-360 series](https://openairdocs.org/engine/lycoming-o-360-series) (registry code 41575, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 401 - Year built: 1969 - Engines: Lycoming O-360 reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Departed: LVK, LIVERMORE, CA - Destination: C83, Byron, CA - Airport: C83, Byron, runway 30, 4,500 × 100 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 51; injuries: none; private; airplane ratings: single-engine sea, single-engine land; medical: class 2, with waivers/limitations; seat: left; flight hours: 790 total ## Weather - Conditions: Visual (VMC), Day - Wind: 210° at 9 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 81 °F, dew point 52 °F - Altimeter: 29.92 inHg - Observed at: KLVK, 12 nm away ## 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 20170725019059A](https://openairdocs.org/incident/20170725019059A), Jul 25, 2017: Lake LA-4, Byron, CA, Substantial damage. A Lake amphibian aircraft N7628L took off from livermore, CA and landed at Byron Airport, CA. Right main gear and nose wheel retracted on landing rollout and… ## Docket (3 files) The files NTSB released with the investigation on January 5, 2021, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=95662. 2.2 MB in all. - FAA examination notes (item 1, PDF, 3 pages, 8 photos, 1.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11645763&FileExtension=pdf&FileName=FAA%20Insp%20Notes%20N7628L-Rel.pdf - Pilot statement (item 2, PDF, 5 pages, 52 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11645113&FileExtension=pdf&FileName=swift%20pilot%20stmt%20170726-Rel.pdf - Photo array (item 3, PDF, 5 pages, 5 photos, 1.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11645133&FileExtension=pdf&FileName=Photo%20Array-Rel.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.