# NTSB FTW94IA032: Fairchild SA227-AC, N688NE, Sugar Land, TX, November 11, 1993 - Type: NTSB incident investigation - Classification: Incident · No injuries · Incident investigation · Final report - Date: November 11, 1993, 14:10 local (20:10 UTC) - Place: Sugar Land, TX - Coordinates: 29.610372, -95.610557 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=29.6104&lon=-95.6106&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 4 uninjured - Status: Completed, report September 13, 1994 - Report: Approved by Office Director - NTSB case key (mKey): 18933 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW94IA032 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/18933/pdf - Page: https://openairdocs.org/ntsb/FTW94IA032 ## Probable cause THE PARTIAL FAILURE OF THE HYDRAULIC PUMP (POWER PACK). ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Gear collapsed, landing - flare/touchdown - hydraulic system,pump - failure,partial (cause) - reason for occurrence undetermined (cause) ## Analysis ON FINAL APPROACH, THE LANDING GEAR WAS EXTENDED, CHECKED DOWN AND LOCKED, AND THREE GREEN LIGHTS WERE NOTED. THIS WAS CORROBORATED BY THE COCKPIT VOICE RECORDER. WHEN THE AIRPLANE TOUCHED DOWN, THE LEFT MAIN LANDING GEAR EITHER COLLAPSED OR RETRACTED. THE LANDING GEAR ACTUATOR RODS, ROD ENDS, DOWN LOCK ROLLERS, AND CAMS WERE UNDAMAGED. DURING POST-INCIDENT EXAMINATION, THE HYDRAULIC POWER PACK MADE A LOUD NOISE AND HYDRAULIC PRESSURE FLUCTUATED BETWEEN 500 AND 1,200 PSI. NO DISCREPANCIES WERE NOTED WHEN THE HYDRAULIC POWER PACK WAS FUNCTIONALLY TESTED AND INTERNALLY INSPECTED. PROCEDURAL ERRORS WERE MADE THAT MIGHT HAVE INVALIDATED THE TEST RESULTS. ## Factual narrative On November 11, 1993, approximately 1410 central standard time, a Fairchild SA227-AC, N688NE, sustained minor damage on landing at Sugar Land, Texas, Municipal Airport. There were no injuries to the captain, first officer, and two passengers. Visual meteorological conditions prevailed for the scheduled domestic passenger flight. The following is based on pilot/operator reports submitted by the captain and first officer. The airplane was operating as Conquest Airlines flight 1041, and the first officer was making the landing. On final approach to runway 17, the landing gear was extended and checked to be down and locked. Three green lights were noted. This was corroborated by the cockpit voice recorder. When the airplane touched down, the left main landing gear either collapsed or retracted and the left propeller struck the runway. A go-around was attempted but abandoned due to "prohibitive" vibrations. According to a Fairchild Aircraft technical representative, the landing gear actuator rods, rod ends, down lock rollers, and cams were undamaged, and it appeared to him that the landing gear had not collapsed but had retracted. When electrical power was introduced and the hydraulic system pressurized, the hydraulic power pack made a loud "clunking" noise. Hydraulic pressure fluctuated between 500 and 1,200 pounds per square inch (PSI). After the airplane was placed on jacks, the landing gear was retracted. No discrepancies were noted, and hydraulic pressure stabilized at 2,000 PSI. The landing gear was then lowered and locked in place. As the hydraulic pressure increased to 1,200 PSI, the "clunking" noise and hydraulic pressure fluctuations resumed. The hydraulic power pack was later functionally tested and internally inspected. No discrepancies were noted. The Fairchild Aircraft technical representative said that due to procedural errors by the testing company, evidence may have been lost and the results were invalidated. ## Aircraft - Registration: N688NE (not matched to a registry record) - Reported make and model: FAIRCHILD SA227-AC - Category: Airplane - Serial number: AC-688 - Engines: GARRETT TPE-331 1000 horsepower turbo prop - Damage: Minor damage - Flight: Part 135 - Operator: Conquest Airlines Corporation - Registered owner: Avline, Inc. - Airworthiness certificate: Standard, Normal - Departed: AUS, AUSTIN, TX - Flight plan: IFR - Airport: SGR, Sugar Land Municipal, runway 17, 8,000 × 100 ft, concrete ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 43; airline transport, flight engineer, commercial, flight instructor; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 1, valid medical--w/ waivers/lim; seat: left; flight hours: 13,000 total, 2,000 in this make and model, 11,000 as pilot in command, 210 in the last 90 days, 70 in the last 30 days, 6 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 170° at 8 knots - Visibility: 15 statute miles - Lowest ceiling: 3,000 ft overcast - Temperature: 75 °F, dew point 70 °F - Altimeter: 30.00 inHg - Observed at: SGR ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Incident 19931111042529I](https://openairdocs.org/incident/19931111042529I), Nov 11, 1993: Swrngn SA226*, Sugaraland, TX, Substantial damage. Left gear collapsed on landing, veered off runway. 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.