infant-mortality failure
n.— «Dr. Ulrich’s analysis of NTSB data proves conclusively what I’ve long believed to be true: By far the highest risk of catastrophic engine failure occurs when the engine is young—during the first two years and 200 hours after initial manufacture, rebuild or overhaul—due to what we refer to as “infant-mortality failures” involving defects in materials and/or workmanship in assembling the engine.» —“The Savvy Aviator #53: The Dark Side of Maintenance” by Mike Busch AVweb Jan. 17, 2008. (source: Double-Tongued Dictionary)
Infant mortality is a well established term for referring to the left-most (decreasing) portion of the even-more-well-known Bathtub Failure Rate model.
Here are some citations from google book search:
“Dynamic Business Strategy: The Art of Planning for Success”
page 19.2
1977
“Advances in Instrumentation”
v.41 pt.1
page 144
1973
“IEEE Transactions on Electron Devices”
v.26 1979 Jan-Jun
page 38
orig. pub 1963
See also this page:
http://quanterion.com/FAQ/Bathtub_Curve.htm
which describes the bathtub model in detail and cites a study in the 1950s as originating it. It also cites a work (of which I would only find newer copies online) published in 1961.