The Valve,check, cataloged under National Stock Number 4820-00-902-4500, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. The manufacturer of record is Sikorsky Aircraft Corporation Dba Sikorsky Aircraft Corp. Government technical data includes 24 specifications, cited from the U.S. Government catalog. The record lists 1 manufacturer part number for this item, enabling identification through both NSN and commercial part number lookups. 2 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4820-00-902-4500 |
| Primary Part Number | SS50-833L8C |
| Item Name | Valve,check |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Manufacturer | Sikorsky Aircraft Corporation Dba Sikorsky Aircraft Corp |
| Status | ACTIVE |
| Flow Control Device | POPPET |
| Surface Treatment Document and Classification | SS-8435,UNITED AIRCRAFT CORP,SIKORSKY AIRCRAFT DIV MFR REF SINGLE TREATMENT RESPONSE |
| Connection Style | FLARED (TUBE) ALL ENDS |
| Mounting Position | VERTICAL |
| Connection Type | THREADED EXTERNAL TUBE ALL ENDS |
| Style Designator | STRAIGHT THRU |
| Material Document and Classification | 11-S-763,CLASS302 FED SPEC 1ST MATERIAL RESPONSE OR QQ-S-764,TYPE303 FED SPEC 2ND MATERIAL RESPONSE OR QQ-S-763,CLASS 304 FED SPEC 3RD MATERIAL RESPONSE OR QQ-S-763,CLASS 316 FED SPEC 4TH MATERIAL RESPONSE OR 11-S-763,CLASS321 FED SPEC 5TH MATERIAL RESPONSE BODY |
| Material Document and Classification | QQ-S-763, CLASS 440C FED SPEC 1ST MATERIAL RESPONSE OR QQ-S-764, TYPE 416 FED SPEC 2ND MATERIAL RESPONSE OR AMS 5643 FED SPEC 3RD MATERIAL RESPONSE FLOW CONTROL DEVICE |
| Material Document and Classification | QQ-S-763, TYPE 303 FED SPEC 1ST MATERIAL RESPONSE OR QQ-S-763, CLASS 304 FED SPEC 2ND MATERIAL RESPONSE OR QQ-S-763, CLASS 321 FED SPEC 3RD MATERIAL RESPONSE SEAT |
| Nominal Outside Diameter Tube Accommodated | 0.500 INCHES FIRST END IN |
| Operating Pressure | 3000.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SINGLE RESPONSE LBS |
| Thread Direction | RIGHT-HAND ALL ENDS |
| Nominal Thread Size | 0.750 INCHES ALL ENDS IN |
| Seat Angle | 37.0 DEGREES FIRST END |
| Specification/standard Data | 78286-SS50-833L8C MANUFACTURERS SPECIFICATION |
| Disk Loading Method | SPRING |
| Surface Treatment | PASSIVATE |
| Media for Which Designed | HYDRAULIC FLUID, MINERAL BASE SINGLE RESPONSE |
| Thread Class | 3A ALL ENDS A |
| Material | STEEL COMP 440C OR STEEL COMP 416 OR STEEL COMP 630 FLOW CONTROL DEVICE |
| Material | STEEL CORROSION RESISTING OR STEEL COMP 303 OR STEEL COMP 304 OR STEEL COMP 316 OR STEEL COMP 321 BODY |
| Material | STEEL CORROSION RESISTING OR STEEL COMP 303 OR STEEL COMP 304 OR STEEL COMP 321 SEAT |
| Thread Series Designator | UNF ALL ENDS |
| Valve Operation Method | AUTOMATIC |
| Acquisition Status | ACTIVE |
| DEMIL Code | DEMIL A — No Demilitarization Required |
| Hazard | No hazard code in the DLA record (HMIC N) |
| Criticality Code | X |
| Part Number | Manufacturer |
|---|---|
| SS50-833L8C | Sikorsky Aircraft Corporation Dba Sikorsky Aircraft Corp (USA) |
| Reference | Meaning |
|---|---|
| 265896 | 3/2 Design control — primary reference U.S. Government activity |
| SS50-833L8C | 3/2 Design control — primary reference U.S. Government activity |
NSN 4820-00-902-4500 is a Valve,check, manufactured by Sikorsky Aircraft Corporation Dba Sikorsky Aircraft Corp, classified under FSC 4820, Valves, Nonpowered. Status: active.
NSN 4820-00-902-4500 has 1 manufacturer part number on file: SS50-833L8C (Sikorsky Aircraft Corporation Dba Sikorsky Aircraft Corp).
Key specifications for SS50-833L8C: Flow Control Device: POPPET; Surface Treatment Document and Classification: SS-8435,UNITED AIRCRAFT CORP,SIKORSKY AIRCRAFT DIV MFR REF SINGLE TREATMENT RESPONSE; Connection Style: FLARED (TUBE) ALL ENDS; Mounting Position: VERTICAL. 24 specifications are documented in the U.S. Government catalog.
No hazard code in the DLA record (HMIC N). Hazard information on this page is shown exactly as it appears in the DLA record.
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-16.
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-18.