FMC True Or False Game.

So true or false, if your low air pressure warning alarm doesn't make a sound your in violation and can be put OOS?

Anyone but Rick 😀

Yer no fun...

Rick

Well, i would have said true, but since you specifically said "doesn't make a sound" I'll guess false, it's ok as long as the warning light works.

Sorry but "Rickipedia"

Need I say more?

Answer: True

CFR §393.51 (a) General Rule. Every bus, truck and truck tractor, except as provided in paragraph (f), must be equipped with a signal that provides a warning to the driver when a failure occurs in the vehicle's service brake system. The warning signal must meet the applicable requirements of paragraphs (b), (c), (d) or (e) of this section.

(c)(2) A warning signal that is audible or visible to a person in the normal driving position and provides a continuous warning to the driver whenever the air pressure in the service reservoir system is at 379 kPa (55 psi) and below, or one-half of the compressor governor cutout pressure, whichever is less.

I'm not Rick. But I like his research and answers.

Answer: True

CFR §393.51 (a) General Rule. Every bus, truck and truck tractor, except as provided in paragraph (f), must be equipped with a signal that provides a warning to the driver when a failure occurs in the vehicle's service brake system. The warning signal must meet the applicable requirements of paragraphs (b), (c), (d) or (e) of this section.

(c)(2) A warning signal that is audible OR visible to a person in the normal driving position and provides a continuous warning to the driver whenever the air pressure in the service reservoir system is at 379 kPa (55 psi) and below, or one-half of the compressor governor cutout pressure, whichever is less.

I'm not Rick. But I like his research and answers.

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

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

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

Rick, Looks like you raided my photo collection with that relic! Haven't seen the wig-wag on anything newer than 1960.

Rick, Looks like you raided my photo collection with that relic! Haven't seen the wig-wag on anything newer than 1960.

Right?

What's interesting about the reg is - it was MEANT FOR a wig-wag. I'm not even sure a small dash light would even qualify as a warning. We had a couple of really old CEO trucks in school that had wig-wags. Old KW's.

Rick