Interpretation ID: nht78-2.4

DATE: 11/28/78

FROM: AUTHOR UNAVAILABLE; J. J. Levin, Jr.; NHTSA

TO: AM General Corporation

TITLE: FMVSS INTERPRETATION

TEXT:

NOA-30

Mr. D. P. Weiher Office of Corporate Safety Emissions and Noise Control AM General Corporation 32500 Van Born Road Wayne, Michigan 48184

Dear Mr. Weiher:

This responds to your August 2, 1978, letter asking whether it is permissible to perform the tests of Standard No. 124, Accelerator Control Systems, with only part of the vehicle mechanism at the designated temperatures. You state further that there is not sufficient time to find an environmental chamber large enough to accommodate the size vehicle that you are testing.

The National Highway Traffic Safety Administration (NHTSA) does not issue approvals of manufacturer's plans for compliance with agency standards. Standard No. 124 mandates that a vehicle shall meet the requirements of the standard at any temperature between -40o F. and 125o F. When the agency tests for compliance with the standard, it finds a chamber sufficiently large to accommodate the entire vehicle and tests according to the standard. Any manufacturer deviation from this accepted test procedure carries with it certain risks that a vehicle may not conform to the requirements.

With respect to the vehicles that you are constructing, you state in your letter that they are being manufactured for use by the army. As such, these vehicles are not required to comply with the agency's safety standards, and the NHTSA would not test these vehicles for compliance.

Sincerely,

Joseph J. Levin, Jr. Chief Counsel

August 2, 1978

Mr. Joseph Levin Office of the Chief Council National Highway Traffic Safety Administration NASSIF Building 400 7th Street, S.W. Washington, DC

Dear Mr. Levin:

We urgently request legal interpretation as to whether our plan for compliance testing meets the intent of FMVSS 124, Accelerator Control Systems, Paragraph S5, requirements which state, "The vehicle shall meet the following requirements when the engine is running under any load condition, and at any ambient temperature between -40o F and +125o F after twelve hours of conditioning at any temperature within that range."

AM General Corporation is in the process of mass producing heavy truck tractors in the 55,000 pound to 75,000 pound GVWR range for the U.S. Army. These diesel engined tractors are of sucn physical size that the number of environmental chambers capable of accommodating them, as well as their availability, is extremely limited. Those capable of accepting this size vehicle are not available within the time frame remaining until the start of our production in November of this year. In consideration of these circumstances, and with the purpose in mind of complying with the intent of the cited Federal standard, we are planning to conduct compliance testing using an actual accelerator control system mounted to a production floor pan and dash panel assembly to which will be oriented the diesel fuel pump with all linkages connected. This assembly will be environmentally soaked to -40oF and then, again, to +125oF, and the linkage connections individually disconnected to measure the return capabilities of the energy sources (springs). Our logic for not testing an entire vehicle (with engine) is based on the contention that engine rock or motion would have an insignificant effect on our accelerator system and, in fact, the heat produced by the running engine would cause the accelerator linkage at the engine-mounted fuel pump to be less than the worse condition under extreme cold, and the temperature increase at this linkage during extreme high ambient would be inconsequential.

Your immediate telephone response with follow-up official written reply would be most appreciated.

Sincerely,

D. P. Weiher

Office of Corporate Safety, Emissions and Noise Control Phone No. 1-313-722-4900

DPW/emr

entir