Skip to content

Atlas / TCDS / H4NM

FAA · Type Certificate Data Sheet

TCDS H4NM

US Helicopter Inc.

Historical Aircraft Rotorcraft Rev 9 12/01/1997 drs.faa.gov ↗

Models covered (3)

Special Airworthiness Information Bulletins (2)

Advisory bulletins on these airframes. Not mandatory like ADs — but operators tracking AD compliance often miss the SAIB on the same component.

Certification basis — 14 CFR

Specific sections

  • Sec. 36.1
  • Sec. 133.1
  • Sec. 137.3
  • Sec. 21.25
  • Sec. 29.15
  • Sec. 91.313
  • Sec. 29.1529

Former holders

  • Williams Helicopter\UNC Helicopter, Inc.
  • Williams Helicopter\UNC Helicopter
  • Williams Helicopter\UNC Helicopter, Inc.\US Helicopter, Inc.
  • Williams Helicopter\UNC Helicopter\US Helicopter, Inc.

Fleet view · 7 registered tails

Engineering specs aggregated from the FAA Aircraft Registry — what every actually-flying tail under this TCDS reports. Median + 10th–90th-percentile range across the active fleet.

Seats

6

n=7

Horsepower

1,150

1,100–1,150

Year of mfr

1967

1965–1988

Engines on the type, by tail count

  • LYCOMING T-53 SERIES 3
  • LYCOMING T-53 1
  • LYCOMING T53-L-11D 1
  • NONE NONE 1

NTSB events

1

across all model variants

Applicable ADs

85

FAA airworthiness directives

Per-tail rate

0.14 events / tail · 12.14 ADs / tail

The TCDS PDF on drs.faa.gov is the authoritative document for design-as-certified weight limits, performance, equipment, AD compliance times, and operating limitations. Open on drs.faa.gov ↗ DRS frequently breaks — when it does, the fleet view above and the cross-links below are usually what you actually need.