FAA plans to mandate inspections for Boeing 757s after an operator discovered cracks in a high-usage jet.
The proposed directive follows a January 2022 service alert from Boeing, highlighting the need for specific inspections.
Boeing’s service alert suggests repetitive inspections to identify potential cracks and stresses the need for necessary repairs.
WASHINGTON D.C. —The discovery of cracks in a heavily used Boeing 757 has prompted the Federal Aviation Administration (FAA) to consider new inspection mandates for the model. Although an immediate order hasn't been rolled out, the FAA is leaning towards the introduction of a proposed airworthiness directive (AD). This proposed course of action follows closely with a January 2022 service alert issued by Boeing itself, advocating for a specific set of inspections for this aircraft model.
The affected 757-200 model, as detailed by the FAA's draft regulation, showcased cracks on both its left and right sides in the station 1640 frame web, precisely between stringer S-14 and S-15. This was brought to light during standard maintenance checks. Delving deeper into the issue, one of the cracks was found to have emerged from a corrosion pit in an open liner hole, which subsequently widened due to fatigue factors.
A closer look by Boeing into the situation revealed that some aircraft had liner holes between stringers that were left unplugged. This anomaly led to stress concentrations around these specific regions, creating a potential environment for cracks. To paint a clearer picture, one aircraft developed a crack after logging 30,200 flight cycles and 89,000 hours of flight. Another exhibited similar deterioration after reaching 40,200 cycles and 90,500 hours.
In response to these findings, Boeing's service alert advised operators to undertake periodic surface high-frequency eddy current inspections, which are known for their effectiveness in detecting such cracks. If these inspections unearth potential threats, Boeing stresses the importance of immediate repairs. This alert applies to both the 757-200s and 757-300s.
Furthermore, the FAA has opened its doors to public opinions and feedback on the directive they're considering, setting a cut-off date of September 5 for contributions. It's worth noting that concerns surrounding potential fuselage cracks in the Boeing 757 aren't new. The FAA had previously issued directives aimed at this very issue in 2018 and again in 2020.
