SERVICE BULLETIN #53

DATE:                       August 20, 1998

SUBJECT:                 Exhaust system cracks

APPLICABILITY:        All Pulsar I XP aircraft with SkyStarís P/N 69296.000 exhaust system

COMPLIANCE:          Mandatory

FROM:                      SkyStar Aircraft Engineering

We have received several reports of cracks developing in the stainless steel exhaust system produced by SkyStar for the Pulsar I aircraft with the Rotax 912 engine. Because the engine mount in this aircraft is the lower cowl and made of fiberglass, special attention must be given this situation due to the remote possibility of heat-caused failure of the engine mount structure and subsequent loss of control of the aircraft.

We are continuing to gather information about problems with the XP exhaust system. If you have encountered any difficulty with this system, either in installation or in operation, it will help us to arrive at an expedient and cost-effective solution if you contact us with a description of your problem. If the system has cracked, a detailed description (or photo, if available) of the location and extent of the crack is very useful.

Until this issue can be resolved, we must insist that this exhaust installation be examined carefully before every flight. Pay particular attention to welds, bends, and flanges. Use a flashlight and inspection mirror as necessary to view all areas of the exhaust components. Any contact between vibrating exhaust components and stationary airframe structure must be remedied before the system is put in service. Even light and occasional contact of this type can be detrimental to the integrity of the exhaust system.

If you have information to offer or questions about this bulletin, contact SkyStar Aircraft at 208-454-2444. Ask for engineering, and state the nature of your call.