NTSB: Chalk's seaplane had cracks in both wings

[Scurrilous]

<snip>

"The Chalk's Ocean Airways seaplane that crashed last month had fatigue cracks on both wings, according to a preliminary report released today by the National Transportation Safety Board.

Investigators almost immediately identified the cracks on the plane's right wing, which broke away when Flight 101 crashed into the ocean near South Beach on Dec. 19. The new report was the first indication of similar damage on the left wing.

"Fatigue, unfortunately, is a pretty insidious thing," said Grant Brophy, a private air-safety inspector and director of flight safety and security at Embry-Riddle Aeronautical University. "This is an issue which any operator of this aircraft would need to look into, not just commercial operators."

All 20 people were killed when the 58-year-old Grumman G-73T Turbo Mallard crashed shortly after taking off from Watson Island on its way to Bimini. Investigators quickly focused on the metal fatigue, but insisted it was premature to assign blame."

http://www.miami.com/mld/miamiherald/13585376.htm

[acmejack]

1. Because they juiced it up with those turbo props

plus the high cycle usage plus the aircraft age. Landings on water (waterings?) are much more stressful on an airframe than those made on actual ground.

[Gregorian]

3. It IS interesting.

I'd like to see the NTSB study, after they finish. The increased stress only occurs for landing cycles. But may have contributed to a decreased number of cycles due to a lowered cycle fatigue limit. If I recall, aluminum doesn't even have an infinite fatigue limit. It's just the number of cycles for a given load. Corrosion may have also played a role.

These kinds of things are just surfacing now. The number of cycles is being reached.

[karlrschneider]

4. I'm surprised they didn't catch it on the annual or 100 hour

Is that a 121 carrier? or 135? don't think I've heard...

[northzax]

2. a 58 year old commercial aircraft?

are you joking? that doesn't sound like much of a good plan. Yes, I know there are plenty of antique aircraft out there, but unless every piece has been removed and replaced, that's a lot of fatigue.