# N840: Delackner Helicopters DH4, registration cancelled 1957-05-06

- Type: Cancelled registration (FAA registry, deregistered aircraft)
- Cancelled: May 6, 1957
- Status when cancelled: Valid registration
- Airframe: [Delackner Helicopters DH4](https://openairdocs.org/model/delackner-helicopters-dh4) (registry code 2850202)
- Serial number: 2
- Type of aircraft: Rotorcraft
- Certificate issued: June 21, 1956
- Mode S code: AB7FD8
- Owner when cancelled: [De Lackner Helicopter Inc](https://openairdocs.org/faa-owner/DE%20LACKNER%20HELICOPTER%20INC)
- Location: [Mount Vernon, NY](https://openairdocs.org/faa-place/NY/Mount%20Vernon)
- Owner type: Corporation
- The mark today: https://openairdocs.org/aircraft/N840
- FAA registry: https://registry.faa.gov/AircraftInquiry/Search/NNumberResult?nNumberTxt=840
- Page: https://openairdocs.org/deregistered/N840-1957-05-06

From the FAA registry file of October 29, 2026, cancelled registrations. Owners' street addresses are left out. The Mode S code belongs to the N-number, not the airframe.

ADs and bulletins for the Delackner Helicopters DH4: https://openairdocs.org/model/delackner-helicopters-dh4.md

## Other aircraft with N840

- [Registered now](https://openairdocs.org/aircraft/N840): North American P-64, S/N 68-3061, built 1940
- [Cancelled 1965-06-03](https://openairdocs.org/deregistered/N840-1965-06-03): Donald R Voland V-1, S/N 1. Owner: [Experimental Aircraft Assn](https://openairdocs.org/faa-owner/EXPERIMENTAL%20AIRCRAFT%20ASSN), [Franklin, WI](https://openairdocs.org/faa-place/WI/Franklin)
- [Cancelled 1950-02-27](https://openairdocs.org/deregistered/N840-1950-02-27): Cessna T-50, S/N 44145. Owner: [Hemmerdinger M E](https://openairdocs.org/faa-owner/HEMMERDINGER%20M%20E), [Arlington, VA](https://openairdocs.org/faa-place/VA/Arlington)

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