The FAA has issued a Safety Alert alerting helicopter operators to a special hazard when operating in the vicinity of hospital helipads.
The SAFO has been issued following reports by pilots and operators of EMS helicopters who experienced interference emanating from active operating MRI scanner equipment, which degraded the indicated directional accuracy of standby compasses and slaved gyroscopic systems.
The pilots reported large deviations in accuracy of their slaved gyroscopic systems while departing from helipads, until flying out of the interfering magnetic field of the MRI.
In summary:
- EMS, law enforcement and military pilots departing from hospital helipads, are advised to verify the accuracy of their magnetic direction indications by comparing their magnetic directional instruments against a known heading for departure.
- Instruments should be re-verified before proceeding “on course.”
- Pilots should be prepared to select the “free” directional gyro function, if available, and “slew” the compass heading to a correctly known magnetic heading.
- Alternatively, pilots may choose to ignore observed erroneous directional indications until clearing the vicinity of the interfering magnetic field of the MRI scanner equipment.
Link to full SAFO