Could Be Evidence Of Bigger Problems

Those tiny fuselage cracks -- they look like scratches, really -- in older commercial aircraft could be a sign of much worse problems to come. That's why the FAA and Boeing are conducting a detailed study on scribe marks to see if they're an indication of structural weakness on the aircraft's skin. Aviation authorities in both the US and Australia say the scribe marks could become deeper cracks and eventually lead to in-flight delamination.

This type of damage typically occurs when an aircraft is being repainted. Workers scrape the paint from the outer hull, taking with it some of the sealant that joins sections of sheet aluminum.

So far, Boeing says about 60 of its aircraft have been found with scribe marks. A company spokesman said Boeing will issue a service bulletin, advising operators to closely inspect the exterior of the aircraft after 4,500 flight operations.

Most of the aircraft affected are 737s -- simply because there are more than 2,800 in service. It's Boeing's most popular line. Some scribe marks have been found on other, older aircraft, including 747s, a 757 and a 767.

Boeing says aircraft found with scribe marks on the fuselage are allowed to return to service, but must be inspected every 250 hours. In many cases, for hardworking aircraft that's as often as once a month.

FMI: www.boeing.com, www.faa.gov