Summary
We propose to adopt a new airworthiness directive (AD) for all The Boeing Company Model MD-90-30 airplanes. This proposed AD was prompted by a report of cracking in a horizontal stabilizer rear spar cap. This proposed AD would require repetitive open hole eddy current high frequency (ETHF) or surface eddy current low frequency (ETLF) inspections for any crack in the left and right side horizontal stabilizer rear spar upper caps, and repair or replacement if necessary. We are proposing this AD to prevent the unsafe condition on these products.