In a public submission, the NTSB has told the FAA it does not understand the foreseeable safety benefit of the FAAs proposed action regarding specific parts of the agencys NPRM on ECi cylinder assemblies. As written, the FAAs NRPM would require thousands of aircraft owners to inspect or replace certain ECi engine cylinders. In its four-page submission, the NTSB cites prior ADs and Mandatory Service Bulletins and suggests that the FAA exclude from the NPRM certain cylinder assemblies (identified by serial number) or take action other than that prescribed by the NPRM. In fact, the NTSB directly states that the FAAs proposed rule would affect many more cylinder assemblies than the NTSB included in our recommendation letter.
In September, six aviation groups, including AOPA, EAA and NATA, asked the FAA to publish data and analysis that drove the agencys proposal, holding the opinion that the FAA had not substantiated support for its proposed action. The NTSB echoed that sentiment, stating that it is not aware of any data that support including specific ranges of serial numbers in the NPRM. Further, the NTSB states that it was involved in meetings between the NTSB, the FAA and ECi and that certain actions proposed by the FAA donot appear to be based on findings from known events or discussions between any of the parties involved. Without visibility of the information driving the proposal, writes the NTSB, we cannot comment on the need for specific actions called for in the NPRM. The NTSB concludes its comments by encouraging the FAA to provide that data and information supporting an expanded scope and compliance time changes in this proposed action.