You REALLY don’t want the TV antenna to break in-flight

If your satellite antenna breaks while at home it is certainly annoying, but the repair process is generally pretty straight-forward and the potential for damage is usually rather low. On airplanes, however, the impact can be a bit different. For example, if the radome housing atop a plane cracks during a flight and the pieces start falling off they potentially can fly into the tail and cause very real damage. So it is probably not particularly good to hear that the LiveTV radome assemblies on certain 737s are showing cracks during routine inspections. Oops.

From the pre-publication filing intended to be posted in the Federal Register on Monday:

This proposed AD would require repetitive detailed inspections for cracks in the radome assembly, and replacement of the radome if necessary. We are proposing this AD to detect and correct cracks in the radome assembly, which could result in the radome (or pieces) separating from the airplane and striking the tail, and consequently reducing the controllability of the airplane

The FAA is following up on reports of cracks on 26 planes, all operated by United Airlines. These planes are approximately 20% of the carrier’s 737 fleet with the LiveTV system installed. The cracks are being blamed on a lack of dimensional controls on the blueprints for older versions of the radomes, an error which was fixed in late 2010. Still, many of the potentially flawed versions were manufactured and installed and their attachment to the aircraft body may result in excessive stress which can cause the failures. The FAA estimates that the inspections will take one hour per plane and that it must be completed within 1,250 flight hours of the Airworthiness Directive being issued. That shouldn’t require planes to be out of service though if a replacement is required it will take more time.