1AD/BEECH 90/91 - Pressurisation Control System Pneumatic Tubing Inspection

COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY

SCHEDULE OF AIRWORTHINESS DIRECTIVES

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Beechcraft 90 and 65-90 (King Air) Series Aeroplanes

AD/BEECH 90/91 Pressurisation Control System

Pneumatic Tubing Inspection

2/98

Applicability: All Beech 90 series aircraft with serial numbers LJ-683 through LJ-1463, LW-177 through LW-347, LA-1 through LA-236 and LL-1 through LL-61.

Requirement: Inspect and re-route the environmental air conditioning and pressurisation control system pneumatic tubing in accordance with Raytheon Aircraft Mandatory SB 2676 dated January, 1997.

Note: FAA AD 97-23-17 Amdt 39-10207 and DGAC AD 97-353-(AB) refers.

Compliance: Unless previously carried out at the next schedule inspection but no later than the next 200 hours’ time in service from the effective date of this Directive.

This airworthiness directive becomes effective on 29 January 1998.

Background: This directive being raised on receipt of FAA AD and advice that when a pilot requested a passenger to open the cabin door a passenger was injured when ejected from the aircraft onto the tarmac.

Subsequent investigation by the manufacturer confirmed that heat from the co pilot’s foot warmer outlet and associated plumbing can soften the plastic pressurisation control system pneumatic tubing sufficiently to cause permanent collapse when the line is subject to vacuum. This will result in loss of vacuum to the outflow/safety valves and this could prevent depressurisation of the aircraft. If the cabin door is operated with the aircraft partially pressurised injury to passengers and/or ground personnel may occur.

The de-icing indicator pneumatic tubing also has the potential for heat damage from the co-pilot’s foot warmer. This tubing could rupture rendering the de-icing indicator inoperative.