scope:

Description of Driving Event:

During two successive missions of the shuttle orbiter OV-99, a television monitor secured by a bracket that was bonded to the wall of the crew module, became detached from the wall (debonded). Following the first incident, it was assumed that an improper bonding technique was the cause of the failure. Remounting was accomplished under close surveillance by quality inspectors. Following the second incident, it was concluded that growth of the structural skin of the wall due to pressurization during flight caused the failure. It was explained that this did not occur on orbiter OV-102 because its wall is thicker and subject to less growth from pressurization. An object as large as a TV monitor detaching from its mount during any phase of a mission could become a hazard to personnel or equipment. The wall section of OV-99 used for mounting the monitor was stiffened with wall doublers to reduce growth from pressurization during launch.