Medium Transport; Low Wing; 2 Turbojet Eng
Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Hazardous Material Violation; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Overcame Equipment Problem; General Maintenance Action
Human Factors; Procedure
The aircraft had been in maintenance for a fuel contamination issue some days prior to the flight. There was a HAZMAT product placed on board the aircraft (Biobor) in the Flyaway Kit in the baggage compartment of the aircraft. The bottle had been placed in a zip lock bag and tucked away in the fly away kit. It is our suspicion (only) that the service center decided it would be good for us to have the left over unused portion. There is no known communication to/from anyone stating that the product had been placed on board inside the tote. The bottle and it's contents were discovered by a [FBO] Maintenance Tech some time after the flight. Suggest mandatory inspections of the Flyaway Kit on preflight and particularly after maintenance. The Flyaway Kit is not something that is on the pilots radar when preflighting an aircraft.
Multiple legs were flown in Aircraft X; including two FAR P. 135 legs; with an undisclosed Hazmat material stored in the rearmost baggage compartment [Aircraft Flyaway Kit]. The material was BioBor; a fuel additive with biocidal properties. It was contained within an unmarked bottle and further sealed in a ziplock bag. It was placed in a bin container which is kept in the baggage compartment to store miscellaneous small items; i.e. static wick covers; fuel test kit; spare chocks; etc. It is believed this material was left over from a fuel tank treatment procedure performed by an OEM (Original Equipment Manufacturer) service facility and placed in back for safe storage back to base; however; our Maintenance nor the flight crew was informed of its presence. This bin is not typically included on preflight inspection. The material was discovered by company maintenance personnel on a routine post flight inspection.
Flight crew reported discovering Hazmat leftover maintenance item had be placed in aircraft Flyaway Kit during preflight.