Abstract : The Federal Aviation Administration (FAA) has directed conversion of all ALSF-1, Category I ILS approach lighting systems with sequenced flashing lights to the Simplified Short Approach Lighting System with Runway Alignment Indicator Lights (SSALR) and Medium Intensity Approach Lighting System with Runway Alignment Lights (MALSR). Although the FAA directive affects civilian aerodromes only, the Air Force is concerned that the lighting change may have an adverse affect on the operational capability of the Air National Guard, Air Force Reserve, and Air Defense Command units which operate from these airfields. Therefore, Headquarters Air Force has requested the USAF Instrument Flight Center (USAFIFC) conduct an in-flight pilot factors (PIFAX) evaluation of the SSALR and MALSR approach lighting system. This evaluation will provide the data necessary for the Air Force to formulate a position on the operational acceptability of the SSALR and MALSR systems. This interim report summarized the IFC/RD findings of the pre-validation portion of the evaluation.