View Full Version : Radar of B-737-500 and radiation
At night I carried out service on B-737-500, + defects, worked in a current of 4 hours under plane. In 4-5 hours has found out that the flight crew has forgotten to switch off a radar and a radar has been engaged all this time and scanned platform. What level of radiation I could get ?
ENGG4LIFE
7th Jun 2009, 00:15
ive been trying to find the answer to that questionfor a long time now. Unfortunately i have not gotten a precise answer yet. All i know is that the longer you are exposed the worse it is. Also your proximity to the antennae affects your exposure. If it is as dangerous as people say i dont know why manufacturers have not put some sort of indication below for ground crew.
Fark'n'ell
7th Jun 2009, 08:25
As far as I know Radar does not emit any radioactive particles.The frequencies that Radar work at can cause some warming of some substances
eg: 2350 Mhz will heat water (your microwave oven) I have been playing with electronic things for nearly 50 years and don't seem to have any problems but then I could be wrong.:ok:
AN72 - firstly, the radar is so-called 'low energy' which is a better start than the old sets. However, any radiation is best avoided. If you were not in front of the scanner I would suggest you probably only acquired a small amount of 'spillage' radiation. Scanner motion on all 737 Classics and onwards is audible, and I guess you will listen for it now?
Apologies on behalf of unknown incompetent pilots that you have this possible exposure and concern. I would suggest you ask for medical advice through either your company or union or both if you have one. I'm sure you'll be fine.
The manuals for our low power radar state that you should not be within 15 feet of the radiating antenna. However ...
The beam is relatively narrow and the antenna only scans through 180 degrees. It doesn't fire backwards.
You should be relatively safe if you were aft of the nose bulkhead or below the line of fire.
Did you happen to notice the tilt setting?
Sonic Bam
12th Jun 2009, 14:22
I think you have to almost hug the thing (which isn't easy as it scans) to absorb any amount of microwave radiation to be concerned about.
If your mind still isn't at rest:
With the tilt setting posted, the scan is going upwards so away from you
Back scatter (e.g. off of hangar doors) attenuates the RF power
You were under the aircraft therefore out of line of sight of the scan so it couldn't have been hitting youOld style air intercept radars were nasty buggers with very high power RF that could hurt you. Modern weather radars put out a tiny fraction of the power of old AI radars.
JRBarrett
12th Jun 2009, 23:24
When I went through U.S. Air Force tech school for the APQ120 airborne fire control radar (some 35 years ago), our very first classroom lecture was on RF hazards and safety.
The biggest health threat wasn't being "cooked" but rather the danger of subtle but potentially serious long-term damage to the lens and retina of the eyes - especially if one knowingly or unknowingly looked right into the boresight of an energized antenna.
The "danger zone" was considered to be within 40 feet directly in front of the aircraft. We were told that RF-induced damage to the lens of the eye might take years to manifest - typically in the form of cataracts. (At a much younger age than one would normally expect such a problem to develop.)
Granted, the APQ120 peak power output was far higher than anything you would be likely to encounter in a modern weather radar.
Also, one should be careful around belly-mounted transponder and DME antennas when working around an aircraft with electrical and avionics energized. On most large aircraft, these systems won't actually transmit with the weight on wheels, but that is not always the case.
A typical high-end transponder like a TDR-94 can produce close to 1000 watts of peak RF power, and if there is an operating ATC radar with interrogator at the airport, (and the transponder control head is not in STANDBY mode), it's quite possible for the transponder to be generating replies every few seconds anytime the aircraft and avionics are powered.
JR Barrett