Weather Radar in Cavok Condition?
 

Hello guys,

I Would like to have your opinion about it. I'm honestly shocked that some arlines request the cockpit crew to keep the weather radar ON for every flight regardless of the weather condition?! Why would you keep a device suffering from wear and tear when you have clear skies and thus obviously not required?
I'm flying on the A320 and Airbus clearly mentions to use it "as required". Luckily the airline I work for follows Airbus SOP in that aspect. I'm not an engineer, but I believe having a microwave running under your balls all the times can't be great for the crew and definetely not for the radar mechanism itself.
Thank you.

Really? Haven't heard about that. Some are argueing wx-radar is reducing risk of bird strike.

Leaving it turned on means you don't forget to turn it on when you may actually need it. Belt and braces.

what schooner said for me as well

Ergo, leaving it on means you might forget to turn it off when you should.

Quite how you'd forget to turn it on if you need it is beyond me.

Checklist will catch that after landing/shutdown. People have flown through weather before because they haven't had the radar on.

Me too. :ok:

But don't forget to turn the tilt to some useful setting!

The radars I am familiar with are transmitting continuously anyway when airborne to provide PWS capability, what you select on your ND and WXR panel will only affect what kind of scan it will perform (in between PWS scans)

the radar beam is pointed forwards ... that is where the energy goes.
and there is plenty aluminium between you and that radar emitter. the microwaves bounce right off aluminium.

sometime i think people have no idea there is a difference between gamma rays and microwaves. oh well.

The people who turn it off to protect themselves from radiation also shouldnt be performing walkarounds next to powered up aircraft (radio altimeters, surprisingly high powered!:})

Talking about Also some pilots try to make a nice landing (landing loooong) and once on the ground trying to make that intersection by hitting the brakes so hard, my ribs still hurt from the seatbelt....:ugh:

Yes it's safer. It's also safer to fly with wings and engines anti ice ON in case we forget in icing conditions...lol. I wanted to say why not keeping also the gears down but since Air India... Haha. I mean it's just common sense. When we check the weather at dispatch and the satellite image shows clear sky, using the radar is just as useless as flying with the dome light on bright during day times like some guys love to do.




Honestly, I'm not flying with radar off to protect myself but mainly to save on maintenance cost. I can still remember my former boss from a small charter company to repeatedly tell me to minimize the use of radar to preserve it.
I do not walk under the 4 RA antennas btw.:p


Well most people like me here are just pilots so yeah I have no clue. I will have a look. Haha


Could not agree more... I hate it also. :}

37 years ago I wrote to Bendix in USA requesting their advice about turning the radar switch to off rather than standby during cruise flight when weather ahead was clear as far as you could see. Our radar on the 737-200 was monochrome type. The chief pilot insisted it was better for the radar to always be left on. He said that electronics don't like being switched off and on. Bendix replied that switching the radar off was perfectly OK and increased the life of the unit.

Lots of pilots are full of personal opinions not always based on facts. Management pilots are not immune to this. I have learned that an aeronautical manufacturer's advice is generally more reliable on technical matters

1. Wear and tear. As long as you don't need to pay the mx bills personally, I wouldn't care. It's like brakes/reverse policies. You do what they want - as long as it's safe. I don't see any safety issues with WXR on from takeoff to landing...

2. With all the radiation that you are exposed to with high altitude flying, weather radar would be the least of my concern. Think RA sensors, other aircraft radars, military radars, sitting on top of 100+ computers in avionics bay, etc.

3. Plenty of people have flown into CBs with weather radar OFF or picture not clearly visible. It's well recognized risk from Airbus. On the topic, why is it possible to almost completely dim WXR returns on ND, and barely able to dim TERR display?

Nice clear day, or night time with a full moon- I probably have it off. As someone alluded to earlier, do you turn on the dome light at midday?

I imagine you may survive an unexpected weather encounter, but you won't survive an unexpected terrain encounter ;)

In the planes I've flown with LCDs, I've never had a problem with dimming the terrain as much as I please. Do you use CRTs?

I've often wondered about why the weather display can be turned so low myself. Doesn't seem to make sense. On airplanes with the new radar, you actually get a message on the ND when weather is detected, prompting you to increase the brightness if required.

When I was working in south east asia the company went through a phase whereby the wx radar was to be switched off unless it was needed - to save cost. With the high relative humidity on the ground condensation would collect on the gimbals which would then freeze at altitude - thus rendering the unit u/s! The law of unintended consequences at play again!

As useless as some operators telling passengers the cabin lights will be dimmed for take off and landing even though it is broad daylight. :ugh:

while all electromagnetic radiation, including radiowave, microwave, infrared, visible light, UV, x-rays, gamma-rays, has common properties, the massively differing energies make it behave very differently.

and that means the energy per photon or minimal unit of radiation.
microwaves and x-rays for example have at least a factor of 1 million between them.

one main effect is that below UV and x-rays said radiation will mostly just heat up body tissue and while that can be bad mostly the heatup is low and you just don't care.

x-rays and above can knock stuff around at a molecular level leading to cancer at very low total power outputs. so they f you up long before they cook you.

and then x-rays and above also don't get stopped by metals as stuff below does.

aluminium foil will happily stop anything below x-rays.


so while mobile phones and microwaves might have negative influences on living tissue apart from heating it up a little bit we have not seen a lot of evidence of that.

x-rays and atomic bombs: ionizing radiation
pretty much everything else: non ionizing radiation
of that everything else ultraviolet is the highest energy still being able to destroy your skin without ionizing it ;P

weather radar even walking through the beam should not be a problem. it needs time to cook you :)
and that's what it would literally do if you stood there long enough. but don't count on feeling it either because we are used to heat coming from the outside so we feel heat only on the skin.
but microwaves cook you evenly more or less.

Checklist will catch that after landing/shutdown. People have flown through weather before because they weren't looking where they were going.

There, I fixed it for ya. I don't see why in broad daylight clear skies you'd have the radar on. If you hit something then, you clearly weren't looking in front . Moonless night is another story.

Just turn it on and LEAVE it on for the flight.

This report is worth having a read of relating to turbulence.

Accident: China Eastern A332 near Tyumen on Jun 18th 2017, severe turbulence causes loss of 4000 feet and injures 26

Common trap on the A320 is forgetting to check the radar display is turned on at the cockpit set up stage. Some people insist on turning it to full dim when leaving the aircraft.

Leaving the weather radar on will also identify you as a civilian aircraft to any military radar systems.

Useful in large areas of the World.

A recent event over the Ukraine may debunk that theory. :(

Despite what happened over the Ukraine, it is still a good idea to leave the radar on as it does help to the military to identify the aircraft as being a civil one.

Modern airborne weather radars fitted to modern passenger aircraft have powers of no more than about 200W, and many are much lower than that.

So; imagine a 200W lightbulb* fitted into a reflector dish and pointing away from you, scanning left and right.

How much light are you going to see when sitting behind the reflector? (none).

Now imagine that reflector fitted on the other side of a substantial aluminium bulkhead.

How much light are you going to see from the bulb now? (less than none).

Radar is the same sort of "radiation" as light - it won't go through the metal - and at these powers, there will be no adverse effect on the human bodies seated in the cockpit.

Any reflections from targets will be 1000's of times lower power than the transmitted output. The radio frequency emissions from your mobile phone into your body will be much much greater than anything received from behind your weather radar and the forward bulkhead.



In a previous life I worked with microwave transmitters - the same sort of thing as a radar. One day I went up a tower to derig a transmitter but forgot to turn it off first. I was standing in front of the dish, making sure I was securely tied to the tower, and for about a minute the transmitter was firing right into my b*lls before I realised my mistake. I have since "helped" produce a very healthy lad who is now 6' 2" and at University.

*in other words, like two 100W domestic lightbulbs

I think it safe to say that even 30 plus years ago those with suitable kit and suitable training could do far far more than simply look at a signal and decide if it was coming from a generic civvie weather radar or not. Sadly as we know how that info is then used is down to who is involved.

Despite the above IMHO it is still worth having having the weather radar radiating in/over some parts of the world...

If your company SOP is to turn it in and leave it on to reduce maintenance on the WX Radar - fine. If your company says turn it on and leave it on because you may forget (or be to stupid) to turn it on when you need it, and you aren't insulted then you are in the wrong profession.

CaptainMongo
on 8 July 2017 you said,
"SOP at our company is NAV lights left on all the time 7-24, 365.
Airbus NAV lights stay in position two, position one if position two inoperative."
pprune.org/tech-log/596779

Since NAV lights are NOT required to be on between sunrise and sunset, are you insulted by your company SOP or in the wrong profession?

I also feel deeply insulted because our SOPs have landing gear item on the landing checklist.

I'm an EE having working a significant part of my career in radar systems integration and test.. and a tight wad as well. On my personal aircraft I always keep the radar on. If your concerned about RF then ditch your cell phone, it right in your face so to speak. In the case of the WXR energy is very well focused and goes where the antenna is pointed vs up your tail pipe. Also the listen time to TX on time of a WXR is typical a 1000 to one. Transmit for a few of micro seconds at a few hundred watts, then listen for a few milliseconds, resulting in an average RF power of a few watts.

On the other side of the equation, two items that take a heavy toll on modern electronics are moisture and thermal cycling. Keeping the WXR on keeps it dry, and turning it on when cold soaked at altitude will cause the solder joints to crack much more so than when turned on leaving the gate. Remember the old tube TV's and even the news ones. Who's TV never dies? ans. the guy that leaves it on 24x7. When does it die, not when it's on, but when it is turned. How many times does an aircraft taxi to the gate OK, and break when fired up from cold for another flight. :ugh:

Russian shootdown over Ukraine
 

With regards to the Malaysian being shot down by Russians over Ukraine.

Do we know if they had the radar on, after all they were looking to shoot down a mil transport.
I imagine the FDR on a 777 picks up if radar on or off?

The NAV lights on our fleet stay on all the time for safety. It is a company policy, one of many we exercise not required by FAR.

I'll ask a more direct question and stop beating around the bush.

Why would a Captain and a Co-pilot forget to turn on the weather radar when required? What would they be doing in the cockpit that they would forget such a basic safety of flight item? I haven't read a good answer to that in this thread yet.

It does worry me that basic airmanship needs to be written in an SOP. Clue? Look out the window. Can you see where you are going? No. Check TAT ref: EAI, 2nd turn on Wx Radar. The problem with too many SOP's is it dilutes airmanship because guys stop thinking. There is no SOP to increase thrust if you need to climb. It is just what you need to do. Let's get back to airman and not trained monkeys.

Goldenrivett, brilliant!

CaptainMongo, try swapping 'Nav lights' for 'Wx radar' and vice versa in your previous post. What difference does it make? Live and let live.

low level windshear can occur in clear skies depending on the topography. As commented, some "States" require weather radar to be on when transiting their airspace. There is no evidence that the WX Radar is harmful to crew as it points forward, although the constant grind of the gimble can be annoying. Guess we just stick to SOPs and let other higher powers decide!

Your cockpit is quiet enough for you go hear your wxr scanning?! Which plane do you fly?! I need to convince my airline to get some of those😀

Never a truer word spoken. This comment should be sent out to every operator and displayed in every crew room.

To illustrate an example. A SE Asian operator had an SOP where in the 737 the PM was required to call "Stable" when the PF had opened the thrust levers to approximately 40%N1 for stabilisation reasons prior to actuating TOGA. In a simulator session, the PM was told over the private intercom system not to call "Stable."

The PF release the brakes and started to trundle down the runway at 40% N1. The airspeed had reached about 45 knots and we had used up 1500 feet of runway when the PF looked across the cockpit to the PM and said accusingly "You forgot to call Stable."

Cue to freeze the simulator and say WTF

A military fire control / search radar is total oblivious to other radar system. On the other hand the US military and US homeland security have systems that can identify both opposition and civil radar equipment by make and model. Within limitation if your WXR beam is pointed up at the cloud tops, insufficient signal will be available on the ground to id the system. On the other hand all US military air defense system have IFF (identify fried or foe) The can read your Mode C/A and S data. But - an enemy aircraft could transmit a Mode C 1200 code. and get shot down as could any one else not sending encrypted IFF 'friend' code.

There used to be a long-standing NOTAM put out by the FAA from the DoD requiring civil traffic in the Gulf to operate their weather radar to assist in identification. The FAA Internationsl Information website no longer has it posted or I can't find it. The old IFIM is gone sadly.