Ice Detectors

[Stearmandriver 2,295]

6 hours ago, ckyliu said:

...In the same vein, is runback icing from early/preventative use of thermal wing anti-ice really a thing? I thought runback was caused by specific types of precipitation such as SLD (super cooled large droplets) or simply severe icing conditions?

Not in normal conditions.  Reference what I said about the anti-ice systems on the Embraer.  We'd fly with the systems activated for long periods of time without any "runback"; the theory behind thermal anti-icing systems is that the protected surface is warm enough to evaporate most moisture from the layer of air flowing over it.  This could obviously be overcome by severe icing / super-cooled large droplet conditions, but that's not what the systems are designed for anyway.  In normal icing conditions, runback is not really a thing. 

[ckyliu 1,749]

@downscc in addition to the article link in my post you quoted, I found another article at https://www.aopa.org/news-and-media/all-news/2013/february/pilot/ice-bridging

I haven't found any studies through Google, but there is an official NTSB bulletin on it https://www.ntsb.gov/safety/safety-alerts/Documents/SA_014.pdf

I also found this mentioned in https://www.ntsb.gov/safety/safety-recs/recletters/A07_12_17.pdf which relates to (NTSB) investigation of Comair Flight 3272, EMB120RT N265CA, Monroe MI, USA, January 9,1997:

Quote

AC  25.1419-1A,  “Certification  of  Transport  Category  Airplanes  for  Flight  in  Icing  Conditions,”  dated  May  7,  2004,  states  that,  although  ice  may  not  be  completely  shed  by  one  cycle  of  the  boots,  the  residual  ice  will  usually  be  removed  by  subsequent  cycles  and  does  not  act  as  a  foundation  for  a  bridge  of  ice  to  form.  Further,  information  gathered  at  a  1997  Airplane   Deice   Boot   Bridging   Workshop,   subsequent   icing   tunnel   test s,   and   flight   tests   conducted as part of the Comair nvestigation revealed that ice bridging did not occur on modern airplanes, which are equipped with deice boots that quickly inflate and deflate. The icing tunnel tests also revealed that thin (1/4 inch or less), rough ice accumulations on the wing leading edge deice  boot  surfaces  could  be,  depending  on  distribution,  as  aerodynamically  detrimental  to  an  airplane’s performance as larger ice accumulations. 

 

Edited December 5, 2018 by ckyliu

[Stearmandriver 2,295]

Regarding Boeing not heating the whole wing... don't worry, we weren't using that part anyway.   I guess.  (You can imagine what the tail looked like).