A-71-046
NTSB Safety Recommendation — Aviation
Recommendation text
ALL HELIO LOWER WING ATTACHMENT FITTINGS OF THE SAME DESIGN AS THOSE FOUND IN N6348V BE INSPECTED FOR CRACKS, ADEQUATE INTERNAL FILLETS, AND SURFACE ROUGHNESS IN THE INTERNAL FILLET AREA AT THE EARLIEST PRACTICAL TIME BY AN FAA-APPROVED METHOD. HIGHEST PRIORITY FOR THESE INSPECTIONS SHOULD BE GIVEN TO AIRCRAFT OPERATED ON FLOATS AND HIGH TIME AIRCRAFT. ALL FITTINGS CONTAINING CRACKS SHOULD BE REMOVED FROM SERVICE. ALL FITTINGS THAT DO NOT COMPLY WITH THE PRESENT MANUFACTURING DRAWING REQUIREMENTS FOR INTERNAL FILLET RADIUS (0.062-INCH) AND INTERNAL SURFACE FINISH (125 MICROINCH RMS) SHOULD BE EITHER REWORKED OR REMOVED FROM SERVICE.
In plain language (FlightFinder summary)
The FAA is urged to ensure that specific wing attachment components on Heli aircraft are examined for damage and manufacturing defects using approved procedures. Inspections should prioritize planes equipped with floats and those with significant flight hours to identify cracks or improper internal fillet dimensions and surface finishes. Any fittings found to be cracked or non-compliant with current design standards must be taken out of service, while others may need repair to meet specifications. This action aims to prevent structural failures by addressing known manufacturing inconsistencies in these critical parts.
This plain-language summary is written by FlightFinder to explain the recommendation above. It is not the official wording — the verbatim NTSB text is quoted above.
Details
| Status | Closed - Acceptable Action |
|---|---|
| Mode | Aviation |
| Closed | Oct 18, 1971 |
| NTSB number | ANC72AA004 |
| Addressees | FAA |
External links
NTSB safety recommendations are advisory; addressees are not legally required to adopt them. Source: NTSB CAROL (public domain).