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SB#21 DHT Main Riser Replacement

by Rigging
Friday, March 22, 1996

ITEM: Dual Hawk Tandem Main Riser Replacement


                                                                                                                                                                                                                                                                                                                                STATUS: Mandatory to replace risers manufactured between 01 June 1994 and 31 July 1995. Recommended replacement of risers manufactured prior to 01 June 1994.

IDENTIFICATION: Strong Enterprises Type VII main risers on Dual Hawk Tandem systems: Part No. 834606 (Master 425 main); and Part No. 834607 (T-520 main) manufactured between 01 January 1994 and 31 July 1995.

BACKGROUND: Several users have reported middle rings that literally broke (separated from the riser and were lost on opening), and several that were deformed (either elongated or "potato chipped"). Investigation revealed that our vendor supplied middle rings which, although dimensionally identical, were machined instead of forged, and therefore not as strong. Visually, the two types may not be reliably distinguished from each other.

SERVICE BULLITEN:Several users have reported middle rings that literally broke (separated from the riser and were lost on opening), and several that were deformed (either elongated or "potato chipped"). Investigation revealed that our vendor supplied middle rings which, although dimensionally identical, were machined instead of forged, and therefore not as strong. Visually, the two types may not be reliably distinguished from each other.

QUALIFIED PERSONNEL: Senior parachute rigger or foreign equivalent.

COMPLIANCE DATE: Sept. 1, 1996

DISTRIBUTION: DHT owners on record, national aero clubs, PIA, USPA, Skydiving, Parachutist, www.StrongParachutes.com.