Weather Radar in Cavok Condition?
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.
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.
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
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...
Despite the above IMHO it is still worth having having the weather radar radiating in/over some parts of the world...
Join Date: Oct 2015
Location: 43N
Posts: 264
Likes: 0
Received 0 Likes
on
0 Posts
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.
Join Date: Jan 2014
Location: N5109.2W10.5
Posts: 720
Likes: 0
Received 0 Likes
on
0 Posts
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?
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.
"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?
Last edited by Goldenrivett; 5th Aug 2017 at 08:57. Reason: CaptainMongo credited for the quote
Join Date: Apr 2010
Location: IRS NAV ONLY
Posts: 1,230
Likes: 0
Received 0 Likes
on
0 Posts
I also feel deeply insulted because our SOPs have landing gear item on the landing checklist.
Join Date: Aug 2011
Location: Upsate NY
Posts: 28
Likes: 0
Received 0 Likes
on
0 Posts
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.
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.
Join Date: Feb 2013
Location: 60 north
Age: 59
Posts: 17
Likes: 0
Received 0 Likes
on
0 Posts
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?
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?
Join Date: Oct 2015
Location: 43N
Posts: 264
Likes: 0
Received 0 Likes
on
0 Posts
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?
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'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.
Join Date: Jun 2000
Location: last time I looked I was still here.
Posts: 4,507
Likes: 0
Received 0 Likes
on
0 Posts
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.
Join Date: Nov 2000
Location: I wish I knew
Posts: 624
Likes: 0
Received 0 Likes
on
0 Posts
Why would you keep a device suffering from wear and tear when you have clear skies and thus obviously not required?
Join Date: Mar 2006
Location: USA
Posts: 2,515
Likes: 0
Received 0 Likes
on
0 Posts
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😀
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. ]
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
Join Date: Aug 2011
Location: Upsate NY
Posts: 28
Likes: 0
Received 0 Likes
on
0 Posts
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.
Last edited by harpf; 6th Aug 2017 at 03:04. Reason: Typo
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.