According the Aspen EFD installation manuals, the Remote Sensor Module has the following mounting limitations:

• The RSM must be mounted within ±4º to the longitudinal axis of the aircraft
• The RSM must be mounted within ±10º to the zero degree roll “wings level” axis
• The RSM must be mounted within ±10º to the zero pitch axis “waterline” of the airframe
• The RSM must be mounted to a relatively flat surface such that when installed it will not deform the aircraft skin and must not allow more than a .030” gap between RSM and skin.
• Mounting the RSM to, or making other penetrations through, the aircraft pressure vessel is beyond the scope of the STC. Separate FAA approval of pressure vessel penetrations required to accommodate RSM mounting is required prior to the installation of the remaining EFD1000 system components under the EFD AML-STC
• Mounting the RSM to the exterior of a composite or fabric skinned aircraft structure is beyond the scope of the STC. To mount the RSM on composite or fabric skin aircraft structures, separate FAA approval of the RSM mounting is required prior to the installation of the remaining EFD1000 system components under the EFD AML-STC