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-   -   Freezing rain (https://www.pprune.org/questions/203207-freezing-rain.html)

catchup 21st Dec 2005 19:16

Freezing rain
 
Are airliner jets certified for flights, take-offs and landings in freezing rain?

regards

er340790 21st Dec 2005 19:36

If anyone would care to try it - there will be freezing (-10C) rain tonight at CYQT.

Nick NOTOC 21st Dec 2005 20:41

JAR FAR 25 certification requirements are as follows:
Intermittent exposure of supercooled droplets of 50 microns, and continues exposure of 40 microns. Freezing drizzle is alreasy 200-500 microns, good luck with freezing rain.

catchup 21st Dec 2005 20:42

@Nick NOTOC
 
Thanks. How can I find out? Opening the window?

4 Conclusions
SLD were found in the atmosphere during short periods, corresponding to a few nautical mile
horizontal extent. The extent and the MVD was for some periods such that the conditions
should be considered as outside the Appendix C envelope defined for aircraft certification.

JAR FAR 25

Nick NOTOC 21st Dec 2005 20:57

Freezing rain is a condition reported by the met office, it is an indication of SLD and as such unsafe for flight.
If however you are flying you may find yourself in freezing rain and not know about this. In such cases you should refere to severe icing procedures (get out of it quickly that is).
ATR seems to know much more about the subject, however only silence from TLS on the matter.

jondc9 22nd Dec 2005 13:15

airliners are not allowed to takeoff or land in freezing rain...if you are at an airport and the freezing rain has stopped in the opinion of the pilot, then you can request a special weather observation to confirm that the freezing rain stopped... you could also make aPIREP and say...freezing rain has stopped

then you takeoff.

I have seen idiot pilots insist that there was no freezing rain, then I opened the sliding window (DV) stuck my hand out (onthe ground) and felt the stinging freezing rain...

there are idiot pilots out there.

j

catchup 22nd Dec 2005 18:15

@jondc9
 
Fly safe.

regards

Gull 30th Dec 2005 03:41

Our Airline defines this a little differently (USA - jet operator).
Freezing rain is a description of a form of precip. and as such, does not prohibit flight.
HOWEVER - Severe icing is a "rate of accumulation" and is considered severe wx. Dispatch into severe wx conditions is prohibited.
Freezing rain may, or may not be severe icing, depending on the severity of the conditions.
So - you are dispatched to an airport forcasting freezing rain at the ETA - Legal???
Yes - provided you have a suitable alternate and do not operate in severe icing.

Clear as mud:D

Doug E Style 3rd Jan 2006 11:31

Re: Freezing rain
 
Freezing drizzle and light freezing rain are catered for in the anti-icing holdover tables. Having said that, a few nights ago at a major European airport, light freezing rain was on the ATIS for several hours and yet a few carriers departed without getting anti-iced.

oldfella 4th Jan 2006 11:58

Re: Freezing rain
 
As an almost old and not so bold flyer I have encountered freezing rain twice. In the first instance - night, climbing (4 engine turboprop), climb became a descent, windows completely iced over. The descent and track progress took us clear and gave the ant-ice system a chance to clear the ice. Second time went to aircraft after about 10 minutes of freezing rain and couldn't believe the build up.

Ice on the wings turns you into a test pilot flying a completely different aircraft. Pick up your bags and go back to the hotel.

Clandestino 4th Jan 2006 21:30

Re: Freezing rain
 
As ATR driver I wouldn't go anywhere near freezing rain and take-off with any airplane is prohibited in moderate freezing rain as there is no guaranteed minimum holdover time. What I didn't know is that even bleed-air deiced jetliners can not land in FZRA. Can anyone else confirm this?

catchup 8th Jan 2006 01:47

Re: Freezing rain
 

What I didn't know is that even bleed-air deiced jetliners can not land in FZRA.
To my understanding, they are not certified for FLIGHTS in FZRA at all.

regards


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