[Federal Register Volume 61, Number 240 (Thursday, December 12, 1996)]
[Notices]
[Pages 65427-65428]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-31584]


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DEPARTMENT OF TRANSPORTATION
National Highway Traffic Safety Administration (NHTSA)


Denial of Motor Vehicle Defect Petition

    This notice sets forth the reasons for the denial of a petition 
submitted to NHTSA under 49 U.S.C. 30162 for the Agency to commence a 
proceeding to determine the existence of a defect related to motor 
vehicle safety.
    In a letter dated May 17, 1966, Mary Walsh-Dempsey, an attorney in 
Scranton, Pennsylvania, petitioned NHTSA to initiate a defect 
investigation on 1976 Chevrolet C10 trucks concerning blade separation 
of the engine cooling fan installed as original equipment and sold as a 
replacement part. The petitioner identified the fan by part number 
336032 (subject fan). As an evidence of the alleged defect, the 
petitioner cites a September 1993 incident in which David Lewis was 
struck by a piece of fan blade, resulting in his death.
    The subject fan is a flexible blade engine cooling fan commonly 
referred to as a ``flex fan.'' The flex fan was used by automobile 
manufacturers as a way to reduce the operating load on engines. The 
flexible metal blades, which are attached to the fan hub or ``spider'' 
by rivets, are designed to flex or ``flatten out'' as the engine speed 
is increased,

[[Page 65428]]

thus reducing the load on the engine. However, these fans may be 
susceptible to fatigue failure of the blade from blade flexing and/or 
various stresses induced by certain engine applications.
    Since the mid-seventies, NHTSA has investigated failures of flex 
fans on several occasions. The largest investigation, Office of Defects 
Investigation (ODI) case C7-24, involved Ford Motor Company (Ford) 
vehicles and resulted in ten safety recalls by Ford. American Motors 
also conducted a safety recall as a result of this case. A review of 
the ODI files reveals there have been two investigations, Engineering 
Analyses (EA8-013 and E81-011), and two Defect Petitions (DP85-022 and 
DP86-03), specific to flex fan failures in General Motors (GM) 
vehicles. The investigations were closed and the petitions were denied 
based on evidence showing a low failure rate for the fans involved. 
EA8-013 and DP86-03 were conducted on the subject fan. This fan was 
used on approximately 2.6 million vehicles that were produced without 
air conditioning and with heavy duty cooling systems. The model years 
and models in which the fans were used are 1973 through 1979 Chevrolet 
and GMC C/K 10, 20, and 30 series light duty trucks and the 1975 
Chevrolet and GMC ``G'' van (subject vehicles).
    Since February 24, 1986, when DP86-03 was closed, there have been 
49 incidents of alleged failure in the subject fan. These incidents 
occurred between May 1986 and March 1996. Reports on all of these 
incidents were provided by the petitioner and GM. There are no reports 
of blade separation in the subject fan in the ODI database, which 
contains records received after January 1, 1981. The estimated 
registered vehicle population of the subject vehicles for calender 
years 1986 through 1996 is 16.4 million, yielding a very low failure 
rate of .29 per one hundred thousand vehicle years of exposure.
    The subject vehicles are very old and range in age from 17 to 23 
years. Vehicle maintenance history and any damage to the fan from 
collision accidents must also be considered when analyzing the alleged 
failures. However, because this information is unavailable, an 
evaluation of the number of reported incidents attributable to such 
factors cannot be made.
    After reviewing the petition and its supporting materials, as well 
as information furnished by GM and information within the agency's 
possession from previous investigations and other related actions, 
NHTSA has concluded that further investigation of the subject vehicles 
concerning the alleged fan failure is not likely to lead to a decision 
that the vehicles contain a safety defect. This is primarily based on 
the very large number of exposure years and the very low failure rate. 
Further commitment of agency resources to this matter is not warranted. 
The agency has accordingly denied the petition.

    Authority: 49 U.S.C. 30162 (d); CFR 1.50 and 501.8.

    Issued on: December 9, 1996.
Michael B. Brownlee,
Associate Administrator for Safety Assurance.
[FR Doc. 96-31584 Filed 12-11-96; 8:45 am]
BILLING CODE 4910-59-P