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The US Federal Aviation Administration published an Airworthiness Directive requiring repetitive inspections for cracking of certain areas of the fuselage skin in all 757-200/-300 aircraft operated in the US. The AD, which becomes effective 25 January 2011, follows two incidents in which cracks of 10-to-18 inches (25-to-45 cm), were found in the crown skin of 757 aircraft. One of these incidents resulted in decompression of the aircraft. The FAA action was imposed without any comment period, and is unusual in the frequency of the inspections required – as low as every thirty cycles if performed by eye, and no more than every 300 cycles if performed as a sliding probe eddy current inspection. While the cost of the inspection is relatively insignificant, its impact remains to be seen. There is currently a severe shortage of feedstock available for 757-200 passenger-to-freighter conversions, and if this new AD pushes the big combination carriers to speed the retirement of their 757 fleets, it will be good news for the all-cargo community. The full text of the AD is available at http://www.regulations.gov/#!documentDetail;D=FAA-2010-1280-0001.
I agree that these 30/300 cycles inspections are relatively insignificant for the operators. It is something that is easy for them to “swallow” and it is certain not a real cause to replace the aircraft. However, if many cracks are detected in the inspections, the repair will result in time and money and it may have some weight on a decision to replace the fleet earlier than was planned.
Taking into account the size of the 757 fleet and age of these aircraft, as well as the fact that so far these cracks have not been detected in significant numbers, I don’t think that a large number of cracks will be found now, unless the maintenance procedure up until now has a serious “bug”.
I don’t believe that this issue will change dramatically the 757 feedstock status.
I think Jacob is correct. However, these situations are a wake-up call for any carrier that is holding on to assets “artificially” longer than plan. In some cases, some of the legacy carriers are well past the 15 year “honeymoon” and will have to grapple with all of the issues that come with “mature” aircraft ownership. The average cargo opertor is pretty good at managing old or mature aircraft issues and this is not a big deal on a jet that is generally, standing the test if time, structurally. If the A.D. accelerates anything, we might see some more ‘sale and lease backs’ propelled. The 757 has thick skin and minimal issues in the area of Chem-mil steps cracking, unlike its little thin skinned 737 ‘classic’ brother. Bless it’s little “9 pallet” heart…