# NTSB ERA24LA386: Cessna 402, N18VV, Boston, MA, September 17, 2024 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 3 · Limited · Final report - Date: September 17, 2024, 17:30 local (21:30 UTC) - Place: Boston, MA - Coordinates: 42.368173, -71.009048 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=42.3682&lon=-71.0090&mi=10 - Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping) - Defining event: [Initial climb: Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330) - Highest injury: No injuries - Injuries: 3 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Eastern Region Aviation - Parties: FAA/FSDO - NTSB case key (mKey): 195144 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ERA24LA386 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/195144/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=195144 - Page: https://openairdocs.org/ntsb/ERA24LA386 ## Probable cause The failure of a solid hydraulic fluid line, which resulted in a loss of hydraulic fluid that prevented the landing gear extension process from completing normally. Contributing to the outcome was the pilot’s failure to fully activate the emergency landing gear extension system. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Use of equip/info: use of equip/system](https://openairdocs.org/ntsb-findings/02063015): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Cessna 402C, 3 cases](https://openairdocs.org/ntsb-findings/02063015/cases.md?model=207590R), [All aircraft, 1,391 cases](https://openairdocs.org/ntsb-findings/02063015/cases.md) - [Landing gear system: gear extension and retract sys](https://openairdocs.org/ntsb-findings/01023230): Aircraft › Aircraft systems · Incorrect use/operation (probable cause); cases with it: [Cessna 402C, 2 cases](https://openairdocs.org/ntsb-findings/01023230/cases.md?model=207590R), [All aircraft, 416 cases](https://openairdocs.org/ntsb-findings/01023230/cases.md) - [Landing gear system: gear extension and retract sys](https://openairdocs.org/ntsb-findings/01023230): Aircraft › Aircraft systems · Failure (probable cause); cases with it: [Cessna 402C, 2 cases](https://openairdocs.org/ntsb-findings/01023230/cases.md?model=207590R), [All aircraft, 416 cases](https://openairdocs.org/ntsb-findings/01023230/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Initial climb: Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330) (defining event); cases with it: [Cessna 402C, 8 cases](https://openairdocs.org/ntsb-events/330/sequence.md?model=207590R), [All aircraft, 994 cases](https://openairdocs.org/ntsb-events/330/sequence.md) - [Emergency descent: Landing gear not configured](https://openairdocs.org/ntsb-events/095); cases with it: [Cessna 402C, 2 cases](https://openairdocs.org/ntsb-events/095/sequence.md?model=207590R), [All aircraft, 584 cases](https://openairdocs.org/ntsb-events/095/sequence.md) - [Landing: Abnormal runway contact](https://openairdocs.org/ntsb-events/090); cases with it: [Cessna 402C, 2 cases](https://openairdocs.org/ntsb-events/090/sequence.md?model=207590R), [All aircraft, 1,506 cases](https://openairdocs.org/ntsb-events/090/sequence.md) ## Analysis The pilot reported that during climb out, he noticed a flicker of both the left and right hydraulic flow lights. He thought the airplane was losing hydraulic pressure, so he tried to extend the landing gear before all pressure was lost. Only the left main landing gear position green light illuminated. The hydraulic flow lights then illuminated steadily. He returned to the airport and performed the emergency landing gear extension checklist; however, the right and nose landing gear did not extend, and he landed with only the left main landing gear extended. A postaccident examination of the airplane revealed that a solid hydraulic line connected to the hydraulic filter was fractured and the system contained no hydraulic fluid. It is likely that the fracture of the hydraulic line and the subsequent loss of hydraulic fluid resulted in the partial landing gear extension. A review of the airplane’s maintenance records could not determine the age of the hydraulic line or if any maintenance had been performed on the hydraulic line. Postaccident testing of the emergency landing gear extension system revealed that if functioned normally when the activation handle was fully extended. Based on this information, it is likely the pilot did not pull the emergency handle out far enough to activate the system. ## Factual narrative On September 17, 2024, about 1730 eastern daylight time, a Cessna 402C, N18VV, was substantially damaged when it was involved in an accident near Boston, Massachusetts. The pilot and two passengers were not injured. The airplane was operated by Cape Air as a Title 14 Code of Federal Regulations Part 135 scheduled passenger flight. According to the pilot, during climb out, he noticed a flicker of both the left and right hydraulic flow lights. He thought the airplane was losing hydraulic pressure, so he tried to extend the landing gear before all pressure was lost. Only the left main landing gear position green light illuminated. The hydraulic flow lights then illuminated steadily. He made the decision to return to the departure airport, notified air traffic control of the situation, and asked for delaying radar vectors to the airport in order to run the checklists. The pilot then followed the "Landing Gear Will Not Extend Hydraulically" checklist. He noted that the landing gear position indicating lights were working when he checked the “press to test,” just as they were on the ground before takeoff. He slowed the airplane to under 130 knots with the landing gear switch already in the down position. He then pulled the “GEAR HYD” circuit breaker and pulled the emergency landing gear extension handle. There was no change of position indicator lights or any indication/noise that the landing gear had extended. He subsequently landed on the left main landing gear and began lowering the airplane’s nose. During the landing roll, the airplane’s right wing contacted a runway light, after which it started to leak fuel. The airplane came to rest upright on the right side of the runway, at an intersection of the runway and taxiway. Further examination of the airplane’s hydraulic system by the operator’s maintenance department revealed that a solid hydraulic line connected to the hydraulic system filter was fractured, and that all of the hydraulic fluid had drained out of the system. The maintenance personnel performed the emergency landing gear extension procedure by pulling the landing gear emergency extension handle all the way out and observed all three landing gear come down and lock. A review of the airplane’s maintenance records could not determine the age of the hydraulic line or if any maintenance had been performed on the hydraulic line. Following the accident, the operator issued a Technical Notice to all maintenance personnel to stress the importance of general inspection criteria while performing maintenance on the airplanes. ## Aircraft - Registration: [N18VV](https://openairdocs.org/deregistered/N18VV-2024-12-21), registration cancelled 2024-12-21, S/N 402C0619, built 1981 (OpenAirDocs) - Reported make and model: CESSNA 402 (C) - Registry model: [Cessna 402C](https://openairdocs.org/model/cessna-402c) (registry code 207590R) (OpenAirDocs) - Registry engine: [Continental TSIO-520 series](https://openairdocs.org/engine/continental-tsio-520-series) (registry code 17040, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 402C0619 - Year built: 1981 - Airframe hours: 29516 - Engines: Continental TSIO520VB reciprocating; Continental TSIO520VB reciprocating - Damage: Substantial damage - Flight: Part 135 - Operator: Hyannis Air Service Inc, doing business as Cape Air - Registered owner: Hyannis Air Service Inc - Airworthiness certificate: Standard, Normal - Last inspection: AAIP, September 3, 2024 - Destination: BHB, Bar Harbor, ME - Flight plan: IFR - Airport: BOS, General Edward Lawrence Logan International Airport, runway 4L, 7,864 × 150 ft, asphalt - Equipment: ADS-B, Auto-pilot, Onboard weather, Stall warning system ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 29; injuries: none; airline transport, commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 1, without waivers/limitations; last flight review May 24, 2024; seat: left; restraint: 3-point; flight hours: 1,777 total, 277 in this make and model, 1,000 as pilot in command, 277 in the last 90 days, 90 in the last 30 days, 7 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 140° at 7 knots - Visibility: 10 statute miles - Lowest ceiling: 19,000 ft broken - Temperature: 73 °F, dew point 43 °F - Altimeter: 30.17 inHg - Observed at: BOS - METAR: KBOS 172154Z 14007KT 10SM BKN190 OVC250 23/06 A3017 RMK AO2 SLP215 T02280056 ## 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 20240917013899A](https://openairdocs.org/incident/20240917013899A), Sep 17, 2024: Cessna 402C, Boston, MA, Substantial damage. On September 17, 2024, at approximately 3 pm EDT, a hyannis air service part 135 (9 or less) commuter aircraft Cessna 402C departed from Boston Logan airport… ## Docket (7 files) The files NTSB released with the investigation on April 1, 2025, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=195144. 4.0 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 11 pages, 2.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17810058&FileExtension=pdf&FileName=6120_Redacted-Rel.pdf - Memorandum for record a�� telephone interview, pilot (item 2, PDF, 1 page, 98 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17810273&FileExtension=pdf&FileName=Memo%20for%20record-pilot-Rel.pdf - Memorandum for record a�� maintenance (item 3, PDF, 1 page, 89 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17889093&FileExtension=pdf&FileName=Memo%20for%20record-MX%20statement-Rel.pdf - Cessna 402 qrh (item 4, PDF, 2 pages, 7 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17910866&FileExtension=pdf&FileName=Cape%20Air%20C402%20QRH%20-%20Extracted%20Pages-Rel.pdf - Investigation photographs (item 5, PDF, 4 pages, 985 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17907522&FileExtension=pdf&FileName=Investigative%20Photos-Rel.pdf - Cessna illustrated parts catalog (excerpt) (item 6, PDF, 1 page, 400 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17809617&FileExtension=pdf&FileName=Cessna%20IPC-Rel.pdf - Technical notice (item 7, PDF, 1 page, 206 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17911064&FileExtension=pdf&FileName=Tech%20Notice%2019OCT2024-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.