This AIR provides information about polymeric materials (Super Absorbent Polymers - SAP) used in Filter Monitors for free water removal, the possibility of migration of such material in to aircraft fuel systems and the potential impact on fuel system operation along with light incidents traceable to the migration of SAP in to the aircraft fuel system are enumerated. The measures taken to minimize SAP migration are also discussed.
There have been a noticeable number of incidents in commercial aircraft related to anomalous response of fuel controls during critical portions of the flight (landing, etc.) that have been traced to the presence of SAP in the fuel system and the impact on fuel system operation. The FAA, while interested in this, has not taken an active role since most of the incidents are outside the U.S. The Energy Institute, responsible for the specification of Filter Monitors has tightened the requirements for media migration in Edition 6 of the relevant specification: EI 1583. The purpose of this AIR is to provide information to the industry, including fuel systems and components designers, ground refueling systems designers and operators, and aircraft operators regarding the above.