Subject: To correct
cracking, which could result in more extensive fatigue cracking and
lead to possible loss of cabin pressure. Manufacturer: Boeing Category: Airframe Summary: The FAA is adopting a new airworthiness
directive (AD) for certain Boeing Model 737-700 and 737-800 series
airplanes. This AD requires performing a one-time high frequency
eddy current inspection for cracking of the backup intercostals
located above the cutout for the forward airstair door; doing
related investigative and corrective actions if any crack is found;
and doing other specified corrective actions if no crack is found.
This AD results from a report of fatigue cracks discovered during a
full-scale fatigue test conducted by the manufacturer. We are
issuing this AD to detect and correct such cracking, which could
result in more extensive fatigue cracking and lead to possible loss
of cabin pressure.