Maintenance and Modifications
Twin Commander Spools Up To Address 690 AD
According to the AD, the condition, if not corrected, could result in structural failure of the airplane.

The FAA has issued an Airworthiness Directive (AD) for Twin Commander 690s, 690As and 690Bs requiring inspection for cracking of the outer fuselage attachments, the lower wing main spar, the vertical channels, the upper picture window channels, aft cabin pressure web, external wing to fuselage fillets and fasteners. It requires modification of the structure with reinforced parts. According to the AD, the condition, if not corrected, could result in structural failure of the airplane.

“About three years ago a routine scheduled inspection of a Twin Commander 690B conducted by a Twin Commander Service Center revealed cracking in the aft pressure bulkhead area of the aircraft. Subsequent inspections of several other 690A and 690B Twin Commanders turned up evidence of similar cracking,” Twin Commander Aircraft president Matt Isley told AIN.