Either the transmitting tube (magnetron), some poor connections that attenuated the signal or the 1950ies-TV-style display
It was not the mechanical parts they were referring to. This was a 1979 P210 with the original radar and a CRT display in the cockpit. I would need to find the manual…
Doesn’t it also “wear out” the radar antenna? I thought I read something like that in the pilot’s guide to a P210 radar.
If you look at the flimsy little motors and gears that move the antenna (they look more like model airplane than anything else) I can understand why the pilot’s guide recommends to use them only when it is necessary. In older planes I had several radar failures but interestingly it was never the mechanical part. Either the transmitting tube (magnetron), some poor connections that attenuated the signal or the 1950ies-TV-style display. I flew through two CBs in my career because of malfunctioning radars.
Last year I did a comparison of the usual weather avoidance tools with many pictures:
http://www.ing-golze.de/blog_marem.jsp
But that was enroute. If there are cell on the ILS I will fly to the alternate, slow down in cruise, hold until the weather is gone or appraoch from the other side if possible. If you really want to avoid a CB which is on the ILS you either have to see it visually or have on board radar. But even then you might just avoid the core and the approach might be very unpleasant. So even though we also have on board radar I would leave that to the bigger planes.
While coming closer to the IAF I realized some nasty dark clouds just on my way to the ILS. At that point I decided to cancel IFR and proceeded at 1500 ft safe below the stuff.
I had a similar situation in Krakow under VFR. There were widespread thunderstorms (not forecast) in the terminal area. The airport refused landing clearance because it had an airliner sitting on the runway waiting for the thunderstorms to move and takeoff. They insisted on this airliner taking off first and my hovering around the thunderstorms. I had to declare an emergency until they sent the airliner off the runway. It was rather early in my flying career and very scary.
“I would like we could discuss the different means, and the strategy to start the approach”
I am only a private pilot with a SE-Cessna-airplane equipped with a stormscope, no on board radar, no data link.
A couple of years ago I was approaching Riga-EVRA coming from Germany. The weather forecast was pretty good for the flight, otherwise I would not have departed.
Some 50 miles west of my destination I could see many buildups in the terminal area which have not been predicted. ATIS reported TCUs with showers in the vicinity.
While coming closer to the IAF I realized some nasty dark clouds just on my way to the ILS. At that point I decided to cancel IFR and proceeded at 1500 ft safe below the stuff.
This strategy is easy and an advantage of small GA planes as a plan B with no terrain on the way and a ceiling high enough.
Two reasons: If you leave the radar on all the time it tends to clutter the navigation display (which is very low resolution by modern standards in our aircraft) and slows down the display updating considerably.
Doesn’t it also “wear out” the radar antenna? I thought I read something like that in the pilot’s guide to a P210 radar.
We normally switch the Radar on when lining up and off on vacating the runway. Interesting to hear about computer problems on older avionics. I would however be very surprised if a certified unit had issues with radiation sat directly behind the transmitter. I thought side lobes from that type of array didn’t appear more than 90° from the intended direction of transmission?
Regarding visual weather avoidance in the cruise, this is the kind of thing I’m talking about (taken at FL100 on a heading to avoid):
Also radar completely wipes out the stormscope of any nearby aircraft.
It may even damage avionics if you are close enough e.g. on the ground. I had the GS input mysteriously blown up on both NAV radios recently.
As to the OP, it appears to ask about approaches rather than departures.
With an approach, one is normally high up (VMC on top) so you can see what is generally around. If the cloud tops are smooth, there isn’t going to be a TCU or a CB in there, so a descent into it is OK.
Then it comes down to the chances of icing. I usually find that the temp inside a cloud is 3C below the air immediately outside, so if just above is 0C you can be assured of icing inside – especially as the tops are the wettest part. So you have to go for a rapid descent strategy. At some airports you can get a hold (rare for piston GA but I got one at Zurich) and that can screw you up, so in that case it’s better to tell ATC you will want a continuous descent due to icing conditions below.
Departures are much more tricky because usually you can’t gauge how high the tops are, visually.
I have encountered this a lot since I started flying bizjets and I don’t quite get why you wouldn’t be transmitting the whole time?
Two reasons: If you leave the radar on all the time it tends to clutter the navigation display (which is very low resolution by modern standards in our aircraft) and slows down the display updating considerably.
And then, our younger co-pilots (who have no children yet) are scared of getting their DNA damaged by reflected microwave energy so we try to keep their level of exposure as low as possible.
When I flew IFR in the AA5 in convective weather, I used a combination of visual avoidance and the storm scope, which were the only real time tools I had. Embedded thunderstorms were a good reason not to go flying that day.
As what next says, a weather radar is a requirement for proper terminal avoidance. As an aside, I’m interested to see you keep your radar on Standby unless you need it – I have encountered this a lot since I started flying bizjets and I don’t quite get why you wouldn’t be transmitting the whole time?
