FMC True Or False Game.

Sorry Errol that would be false. A visual alarm will be just fine.

Here's where it gets a little weird.

if the truck HAS an "audible alarm" - it MUST WORK.

Older trucks had a "wig wag" visual alert.

You might see them in a museum quality truck - or maybe a school bus - but you ain't gonna see a wig wag in a modern truck.

An "idiot light" on the dash - qualifies as a "visual alert" - but they're so small that they are ALWAYS accompanied by a REALLY ANNOYING BUZZER - like a seat belt alert on steroids. Kinda hard to miss, nor would you want to. That REALLY ANNOYING BEEP when you turn the key in any modern truck to the run position - is the AUDIBLE ALARM. The reason WHY it beeps is so YOU KNOW IT'S WORKING. This is the alarm that comes on, when you "fan the brakes" during an air brake test, to bleed off pressure to TEST THE ALARM and the TRACTOR PROTECTION VALVE (55-65PSI/20-45PSI).

If you're losing air THIS FAST (that the alarm goes off) - you are right above the point where your Tractor Protection Valve (trailer air supply) is going to pop - locking the brakes on the trailer axle with spring brakes - and you will no longer have enough pressure soon, to keep the spring brakes on the tractor axle (parking brakes - usually on only ONE rear axle, but can be on BOTH - I've seen units both ways) from activating.

If this happens rapidly - say - while you're doing 60MPH on the highway - the results aren't going to be pretty.

From the KW T-6800/800 Manual: If the pressure in either or both circuits falls below 65 psi (448 kPa), a red warning light in the gauge will turn on and an audible alarm tone will sound when the engine is running.

Every modern truck is going to have both an IDIOT LIGHT and an AUDIBLE ALERT. If it is EQUIPPED WITH BOTH - then BOTH MUST BE WORKING OR -

VIOLATION - OUT OF SERVICE.

Really - the "visual alert" part of the regulation was for WIG WAGS - it's highly unlikely an inspector would even notice the idiot light burnt out - he's listening for the alarm, and waiting for the TPV to pop.

Rick

Damn, Rick really went above and beyond on this one, even more so than usual!

Cwc made me go back and look:

Sorry Errol that would be false. A visual alarm will be just fine.

CFR §393.51(c)(2):

..... audible OR visible .....

Ooops!