1、Lessons Learned Entry: 1734Lesson Info:a71 Lesson Number: 1734a71 Lesson Date: 2006-06-21a71 Submitting Organization: DFRCa71 Submitted by: William LokosSubject: Antenna Pole Failure Abstract: A wooden utility pole in substandard condition failed during a wind storm destroying multiple communication
2、s antennae.Description of Driving Event: On the morning of Monday, November 28, 2005 personnel of the NASA Dryden Communications Facility at building 4824 discovered that antenna support pole number 2 had fallen to the ground sometime over the preceding weekend. It had broken at about two feet below
3、 grade. Visual inspection revealed wood decay at the location of the break. In its fall it stripped off most of the antennae from the North side of pole number 1, which it narrowly missed hitting directly. Before reaching the ground, it also impacted an extendable quad-yagi antenna. No one was injur
4、ed. Within the potential reach of the 78 ft. tall pole was all of B4824 with its human work spaces, and many other communication assets. Root causes for the pole failure are: 1. Inadequate original pole preservative treatment that allowed wood decay. 2. Suspected unusually high local wind possibly d
5、ue to mountain wave activity. 3. No requirement for periodic pole inspection and maintenance. Lesson(s) Learned: 1) The Center must have in-house experience to verify contractor functional adequacy or to hand off clear requirements to a contractor. 2) Thorough diligence at the detail level is necess
6、ary for hazard mitigations even when things seem Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-routine and safe. Recommendation(s): 1. Develop a requirement for periodic inspection and maintenance of all (not just antenna support poles) wood utilit
7、y poles. 2. Invasively inspect all antenna support poles above and below grade every 5 years. 3. Pressure treat all antenna support poles with wood preservative below grade every 5 years. Evidence of Recurrence Control Effectiveness: N/ADocuments Related to Lesson: N/AMission Directorate(s): a71 Spa
8、ce Operationsa71 Sciencea71 Exploration Systemsa71 Aeronautics ResearchAdditional Key Phrase(s): a71 Program Management.a71 Program Management.Role of civil service technical staff versus contractor staffa71 Systems Engineering and Analysis.Long term sustainability and maintenance planninga71 Safety
9、 and Mission Assurance.a71 Safety and Mission Assurance.Early requirements and standards definitiona71 Safety and Mission Assurance.Maintenancea71 Safety and Mission Assurance.Product AssuranceAdditional Info: a71 Project: N/AProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Approval Info: a71 Approval Date: 2008-10-01a71 Approval Name: mbella71 Approval Organization: HQProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
