CRJ-200 Landing Gear Quest.?

[dueguard1]

Can someone explain how proximity sensors work on the CRJ? Does is use aircraft weight, infared light or something else?

 

[The_Russian]

Do you mean Air-Ground sensors? Those are magnetic.

 

[Edge540]

Can someone explain how proximity sensors work on the CRJ? Does is use aircraft weight, infared light or something else?

The PSEU uses the Proximity sensors to detect changes in the magnetic field at the sensor. When a piece of metal is close, the magnetic field changes and it means something. There should not be any physical contact between the proximity sensors, because all they detect is proximity.

The WOW switches are squat switches that require weight.

 

[paddlehigh]

radar altimeter

 

[The_Russian]

radar altimeter

Huh? uh.....no?

 

[urflyingme?!]

Radar altimeter is used for some of the systems but has nothing to do with the PSEU

 

[DoinTime]

Can someone explain how proximity sensors work on the CRJ? Does is use aircraft weight, infared light or something else?

They use ball bearings.

 

[xjcaptain]

to be more specific......30 weight ball bearings and 3 in 1 oil.

 

[wilde737]

no it's the Retro-incabulator! Through the non reversable tremupipe, and the differential girdle sping!
http://www.youtube.com/watch?v=gxF8MIJf0_U

 

[Lear70]

You guys crack me up... why you gotta mess with the FNG who wants to know about the airplane? LOL

Edge has it correct. NO contact, just "proximity" or nearness to one another that makes them react.

Kind of like Britney Spears and trailer park outfits. *POW*

 

[AvroGuy]

They use ball bearings.

you could not be more wrong. You must remember, these things are built by french canadians so that can only mean that it really uses some odd ball versions of teh flux capacitor.

 

[paddlehigh]

flux capasitor transitor sensor

 

[CitationLover]

who cares

 

[CarjCapt]

Wrong Bob, tell him what he would have won!!!

Behind door number one is: Johnson Rod...

 

[CaptainChris77]

You guys crack me up... why you gotta mess with the FNG who wants to know about the airplane? LOL

Edge has it correct. NO contact, just "proximity" or nearness to one another that makes them react.

Kind of like Britney Spears and trailer park outfits. *POW*

ZING.... Britney Spears---awesome.

 

[ArcticFlier]

to be more specific......30 weight ball bearings and 3 in 1 oil.

......and fetzer valves................


AF

 

[Hobit]

Come on Folks... The PSEU needs a Fetzer Valve input to correctly schedule the ball bearing lubrication at a 3:1 level.

Or in real life.... Like others said, A magnetic field sensed because of a proximity of two metal thingies. One of them is on a moving part and the other is mounted with wire coming out of it. If a magnet is near the sensor it sends a signal to the PSEU.

the following was taken from an NTSB report at:
http://www.ntsb.gov/ntsb/brief2.asp?ev_id=20050617X00804&ntsbno=LAX05FA202&akey=1

1.3.3.3 Proximity Sensor Electronic Unit

The proximity sensor system operates by identifying the position of targets and giving a resulting command. The system is comprised of the Proximity Sensor Electronic Unit (PSEU), multiple proximity sensors, and numerous switches. The PSEU receives information via proximity sensors to determine the position of the nose landing gear.

The PSEU serves several functions within the NLG system:
-determines if the airplane is on the ground or in the air
-monitors for gear up, down and transit status
-determines if the landing gear doors are open or closed
-provides commands to extend or retract the landing gear
-provides commands to open and close the NLG forward doors
-records faults of any contradictions or discrepancies

 

[Hobit]

DANG AF beat me to it!!!!

 

[00Dog]

I have a better CRJ-200 gear question: Why the hell does it sound like a bomb just went off? Scared the crap out of me the first time I rode on one and still scares me even though I know it is coming.

 

[Edge540]

I have a better CRJ-200 gear question: Why the hell does it sound like a bomb just went off? Scared the crap out of me the first time I rode on one and still scares me even though I know it is coming.

Blame Canada.

 

[FmrFreightDog]

I have a better CRJ-200 gear question: Why the hell does it sound like a bomb just went off? Scared the crap out of me the first time I rode on one and still scares me even though I know it is coming.

Makes me jump a little too when I'm in the back, and I fly the damm thing.

 

[DrewBlows]

I have a better CRJ-200 gear question: Why the hell does it sound like a bomb just went off? Scared the crap out of me the first time I rode on one and still scares me even though I know it is coming.

I have a theory on that. It's always loud, but I think that it is louder when the airplane is faster. Normally the gear would go down at approximately 185 KIAS, but on occasion it may be lower (when slower speed is required by ATC for example).

Of course this is unprovable, as no one in their right mind would ever ask the pilots how fast they were going when they put the gear down. That's probably why it's so loud to begin with. The Bombardier engineers sitting in the back of the airplane never bothered to ask the pilots how fast they were going when the gear was extended.

 

[blesko]

......and fetzer valves................


AF

and some prestone anti-freeze....uh..wait..make that quaker state

 

[Lear70]

It's about the pressure in the hydraulic lines are how fast and hard they slam those releases on the gear doors open.

Asked one of the Bombardier mechanics one time when we picked an aircraft up from factory; he says it's just as loud in the hangar when they do the gear swings on jacks during certification, too.

Never said WHY the pressure is so high and not restricted or something. I'd worry about blowing a line, but evidently they're not, so what do I know.