Boeing has certified an improved proximity sensor for Boeing 737 aircraft. Proximity sensors on the 737 sense the position of the landing gear, doors, and leading edge slats and flaps.

The new Crane proximity sensors feature titanium housings which substantially improve reliability in harsh locations, providing increased protection against vibration, shock, and temperature extremes. In addition, the new design provides increased protection from intrusion of moisture, humidity and corrosive fluids such as de-icing solution. Boeing has issued a Service Bulletin and Service Letter recommending operators implement a retrofit program to reduce service delays and/or flight cancellations. The new proximity sensors are standard on 737 production aircraft and are available for retrofit.