The Valve,check, cataloged under National Stock Number 4820-00-438-0631, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. The manufacturer of record is Northrop Grumman Systems Corporation Dba Northrop Grumman Systems Corp Div Northrop Grumman Aeronautics Systems. Government technical data includes 30 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through both NSN and commercial part number lookups. 2 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog.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 | 4820-00-438-0631 |
| Primary Part Number | A51H9065-1 |
| Item Name | Valve,check |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Manufacturer | Northrop Grumman Systems Corporation Dba Northrop Grumman Systems Corp Div Northrop Grumman Aeronautics Systems |
| Status | ACTIVE |
| Flow Control Device | POPPETPOPPET |
| Surface Treatment Document and Classification | MIL-S-5002 MIL SPEC SINGLE TREATMENT RESPONSE |
| Connection Style | EXTERNAL SEAT FOR GASKET SEAL (BOSS) SECOND ENDEXTERNAL SEAT FOR GASKET SEAL (BOSS) SECOND END |
| Connection Style | FLARELESS FIRST ENDFLARELESS FIRST END |
| Mounting Position | HORIZONTAL OR HORIZONTAL OR VERTICALVERTICAL |
| Connection Type | THREADED EXTERNAL TUBE FIRST ENDTHREADED EXTERNAL TUBE FIRST END |
| Connection Type | THREADED EXTERNAL BOSS SECOND ENDTHREADED EXTERNAL BOSS SECOND END |
| Style Designator | STRAIGHT THRU |
| Nominal Outside Diameter Tube Accommodated | 0.125 INCHES SECOND END IN |
| Nominal Outside Diameter Tube Accommodated | 0.125 INCHES SECOND END0.250 INCHES FIRST END IN |
| Operating Pressure | 3000.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SINGLE RESPONSE LBS |
| Thread Direction | RIGHT-HAND SECOND ENDRIGHT-HAND SECOND END |
| Thread Direction | RIGHT-HAND FIRST ENDRIGHT-HAND FIRST END |
| Nominal Thread Size | 0.437 INCHES FIRST END0.437 INCHES FIRST END IN |
| Nominal Thread Size | 0.312 INCHES SECOND END0.312 INCHES SECOND END IN |
| Seat Angle | 12.0 DEGREES FIRST END |
| Maximum Operating Temp | 275.0 FAHRENHEIT SINGLE RESPONSE275.0 FAHRENHEIT SINGLE RESPONSE DEGF |
| Disk Loading Method | SPRINGSPRING |
| Surface Treatment | PASSIVATE |
| Media for Which Designed | HYDRAULIC FLUID, SILICATE-ESTER BASE SINGLE RESPONSE |
| Thread Class | 3A SECOND END3A SECOND END A |
| Thread Class | 3A FIRST END3A FIRST END A |
| Thread Quantity Per Inch | 20 FIRST END20 FIRST END |
| Thread Quantity Per Inch | 20 SECOND END20 SECOND END |
| Material | STEEL COMP 440C FLOW CONTROL DEVICE |
| Material | STEEL COMP 440C FLOW CONTROL DEVICESTEEL COMP 630 SEAT |
| Material | STEEL COMP 630 SEATSTEEL COMP 630 BODY |
| Thread Series Designator | UNIFIED NATIONAL JOINT (UNJ) SECOND END |
| Thread Series Designator | UNIFIED NATIONAL JOINT (UNJ) SECOND ENDUNF FIRST END |
| Valve Operation Method | AUTOMATICAUTOMATIC |
| 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 |
|---|---|
| A51H9065-1 | Northrop Grumman Systems Corporation Dba Northrop Grumman Systems Corp Div Northrop Grumman Aeronautics Systems (USA) |
| Reference | Meaning |
|---|---|
| A51H9065-1 | 5/9 Secondary reference Northrop Grumman Systems Corporation |
| 4C2240-1 | 3/2 Design control — primary reference U.S. Government activity |
NSN 4820-00-438-0631 is a Valve,check, manufactured by Northrop Grumman Systems Corporation Dba Northrop Grumman Systems Corp Div Northrop Grumman Aeronautics Systems, classified under FSC 4820, Valves, Nonpowered. Status: active.
NSN 4820-00-438-0631 has 1 manufacturer part number on file: A51H9065-1 (Northrop Grumman Systems Corporation Dba Northrop Grumman Systems Corp Div Northrop Grumman Aeronautics Systems).
Key specifications for A51H9065-1: Flow Control Device: POPPETPOPPET; Surface Treatment Document and Classification: MIL-S-5002 MIL SPEC SINGLE TREATMENT RESPONSE; Connection Style: EXTERNAL SEAT FOR GASKET SEAL (BOSS) SECOND ENDEXTERNAL SEAT FOR GASKET SEAL (BOSS) SECOND END; Connection Style: FLARELESS FIRST ENDFLARELESS FIRST END. 30 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.