Aviation Investigation Report A98H0003
2.14.2 FAA Oversight (Surveillance) of the IFEN STC Project
In its capacity as a Designated Alteration Station (DAS), Santa Barbara Aerospace (SBA) was responsible for ensuring that the IFEN system complied with existing regulations, and that it was safely integrated into the aircraft design. As SBA was operating on behalf of the FAA, it was the responsibility of the FAA to ensure that SBA had the expertise to carry out its duties. At the time this Supplemental Type Certificate (STC) was being certified, the FAA procedures in place to oversee the delegation of authority to a DAS for STC certification did not ensure that anomalies could be identified and corrected.
As reflected in the electrical load analysis document used in the initial IFEN design and development work completed by Hollingsead International (HI), there was an intention to power the IFEN from the cabin bus. As the IFEN development work progressed, HI determined that there was insufficient electrical power available from the cabin bus, and changes were made to the drawings to take power from the 115 V AC Bus 2. It could not be determined how much of the preliminary design work by HI was shared with SBA. The Letter of Intent (LOI) that was submitted by SBA to the FAA reflected what appeared to be the initial intention for the installation. While an amendment would be expected with such significant changes, the LOI was not amended to reflect the design changes. Also, the FAA review process to accomplish the oversight function was unlikely to discover such anomalies, as it relied on being notified by the DAS of any change to the scope of the project.
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