[Federal Register Volume 59, Number 145 (Friday, July 29, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-18515]
[[Page Unknown]]
[Federal Register: July 29, 1994]
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DEPARTMENT OF TRANSPORTATION
Denial of Petition
This notice sets forth the reasons for the denial of a petition
submitted to the National Highway Traffic Safety Administration (NHTSA)
under 49 U.S.C. Sec. 30162 (formerly Section 124) of the National
Traffic and Motor Vehicle Safety Act of 1966, as amended.
In a letter dated March 14, 1994, Dennis and Sharyn A. McLain
petitioned NHTSA to ``initiate a defect investigation into and recall
all Chevrolet Blazers, and other vehicles, with fuel systems that do
not possess mechanisms to prevent the escape or continued supply of
fuel in the event of a crash.'' As evidence of the alleged defect, the
petition cites a March 20, 1992, accident that resulted in fatal
injuries to Kristin Dawn McLain Sutherland. In the accident, Ms.
Sutherland's vehicle, a General Motors Corporation (GM) small-size (S/
T) utility vehicle with a fuel injected engine (``subject vehicle''),
was involved in a severe frontal crash. After a second impact, a fire
started in the engine compartment of the Blazer, a 1987 model equipped
with a throttle body injected 2.8 liter V-6 engine. The fire spread to
the occupant compartment, contributing to Ms. Sutherland's injuries.
The letter also alleges additional defects in the fuel system of the
Blazer, related to the potential for fuel leakage or fire after a front
impact collision.
Regarding the issue of electric fuel pump control after collision
impact, there are two general approaches used by motor vehicle
manufacturers to stop the flow of unwanted fuel from the fuel pump. The
most common approach is based upon detection of engine stoppage. When
the fuel pump control logic receives a signal that the engine has
stopped running, power to the tank-mounted electric fuel pump is shut
off. This method produces a result similar to that seen in carbureted
vehicles using mechanical fuel pumps, which were typically driven by
the engine camshaft. An alternate approach is based upon detection of
impact severity. This method uses an electro-mechanical inertia switch
in the fuel pump circuitry. If the switch detects a significant
collision impact, the switch will break the electrical circuit to the
fuel pump and remain open until it is manually reset. Ford is the only
major manufacturer that has adopted the impact detection approach in
vehicles sold for use in the United States.
GM uses a variation of the engine stoppage approach, supplying
power to the fuel pump only when the ignition switch is ``on'' and the
engine control module is receiving reference pulses from the
distributor or the oil pressure switch is closed, both of which
indicate the engine is operating. Thus, contrary to the petitioners'
allegation, the GM fuel system design does include a ``mechanism to
prevent the escape or continued supply of fuel in the event of a
crash.''
The petition asserts two general deficiencies in the design of the
fuel system in the subject vehicles: (1) that absent a mechanism to
prevent such occurrence, the fuel pump will continue operating after
the system has been damaged in a collision; and (2) that additional
defects in the system design and construction render it prone to suffer
such damage in a frontal impact collision.
To evaluate whether the subject vehicles demonstrate an inordinate
rate of fuel leaks and fires in frontal impacts, the Office of Defects
Investigation (ODI) analyzed data from various accident reporting
systems. ODI compared the post-collision fuel leakage and fire
experience of the subject vehicles, and other GM vehicles using fuel
injection and electric fuel pumps, with that of peer populations,
including Ford vehicles using an inertia switch.
Data from NHTSA's Fatal Accident Reporting System (FARS) was
analyzed to assess vehicle fire experience in severe accidents,
involving one or more fatalities. The data were analyzed to determine
the incidence of fire among vehicles involved in fatal accidents.
Additional analyses were performed using Michigan State accident
records. The Michigan records are compiled from all accidents where a
police report is filed and, thus, include the full range of crash
severities as compared to fatal-only crashes in FARS. Michigan's
database also includes an indication of fuel leakage (with or without
fire) as an added element for comparative analysis. A third reporting
system, the National Accident Sampling System, was used as a general
index of the comparative fire experience between GM and Ford vehicles
that were involved in crashes that required subsequent towing.
ODI's analysis considered accident data for the general case (all
impact modes) and for the frontal and side crashes, separately. In each
case, ODI's analysis found no statistically significant difference in
the rate of fuel leakage and/or fire between the subject vehicles and
peer populations of small-size utility vehicles, including Ford's
Bronco II. Additional analyses comparing the experience of GM passenger
cars with those of Ford and other manufacturers produced similar
results. In some of the comparisons, GM vehicles exhibited a slightly
higher likelihood of fire or fuel leakage than the Ford vehicles. In
other peer comparisons, the relationship was reversed. However, in no
case was there a difference between GM and Ford that was statistically
significant. Finally, a comparison of the subject vehicles (with fuel
injection) with carbureted S/T utility vehicles, equipped with
mechanical fuel pumps, did not show a significant difference in the
rate of fuel leakage events in frontal impact collisions.
In summary, the GM fuel system design does include a mechanism
intended to address the concerns expressed in the petition regarding
post-collision fuel pump control. GM's approach to this problem is
similar to that employed by most other manufacturers. In addition, ODI
has received no other complaints regarding any of the defects alleged
by the petitioners in the fuel system of the subject vehicles. Most
importantly, a comprehensive analysis of real-world crash data does not
indicate that the subject vehicle, or vehicles equipped with a similar
fuel delivery system, exhibit higher fuel leakage and/or fire rates in
crashes when compared to other vehicles.
In consideration of the available information, NHTSA has concluded
that there is not a reasonable possibility that an order concerning the
notification and remedy of a safety-related defect in relation to the
petitioners' allegations would be issued at the conclusion of an
investigation. Since no evidence of a safety-related defect trend was
discovered, further commitment of resources to determine whether such a
trend may exist does not appear to be warranted. Therefore, the
petition is denied.
Authority: 49 U.S.C. Sec. 30162; delegations of authority at 49
CFR 1.50 and 501.8.
Issued on: July 26, 1994.
William A. Boehly,
Associate Administrator for Enforcement.
[FR Doc. 94-18515 Filed 7-28-94; 8:45 am]
BILLING CODE 4910-59-M
