Known Ice

[Iced Up]

Here it is again folks. That pesky question that pops up year in and year out.

What is "known ice"???

 

[starcheck1]

Frozen aircraft

Known ice..........i have always known as any forcasted (AIRMET or SIGMET) or Reported icing conditions (pirep) but is debatable i guess. Known ice for real.........when the wing turns white and you cant see outside anymore. Anybody else have any different interpretations??

 

[Checks]

Your right about Known Ice, the FAA has ruled that a forecast of icing is "Known Ice"

Where the confusion comes in is that there is an AC out regarding aircraft not certified as Known Ice but that still have all the deicing equipment. These aircraft were manufactured in the 70's(I think)
Then Known Ice becomes when you actually see it on your wings.

For the average Joe Cessna 172 driver out there, Known Ice is when it is forecast or reported.

 

[SierraPilot]

You can only get known icing from pirep's or airmets, most forcast can only show you areas where known freezing levels exist, which is not a idicator of known icing conditions as you need more then just freezing temperatures to form ice.

Ryan

 

[bigsky]

Ice is slightly hard to predict 100%. It is even possible for 1 airplane, lets say a jet, to fly through some weather and not pick up any icing and at the same time a light aircraft fly through same area and pick up severe icing.
Although a pirep is the best indication of icing I would have to guess that any FSS breifing, whether it be an airmet, sigmet, or pirep would count as Known icing. I had a student encounter icing in a pa28 and declare an emmergency and they were violated. I dont believe it was forcast however if I remember correctly the FAAs point was they did not exercize good judgement by entering IMC in below freezing conditions.
I guess in my opinion if it is likely then one should be properly equipped or have plan be to stay out.

 

[Flymach2]

Hi...

The following is an excerpt from an article printed about the subject at hand. I hope it's helpful.

Regards


The leading case, Administrator v. Bowen, arose from a December 1972 solo flight in a Bellanca 17-30A from Mineral Wells, Texas, to Marion, Ind. At the time of the flight, the Area Forecast, Airmet 1 and Sigmet Charlie 1 called for isolated or occasional moderate or severe icing in clouds or precipitation. The destination airport was IFR under a low overcast upon the pilot's arrival. He was required to miss the initial approach and crashed due to an excessive accumulation of rime ice while attempting a second approach.

The commercial pilot was injured but survived. The Administrator initiated proceedings against him, alleging that he had operated the aircraft in noncompliance with its established operating limitations and, in so doing, had also operated in a careless or reckless manner. On appeal, the Board expressly rejected the pilot's argument that mere forecasts of icing, in the form of the Area Forecast, Airmet and Sigmet, could not constitute "known icing" within the meaning of the POH. At the same time, the Board suggested that a pilot report of icing (or no-icing) might constitute more accurate information about actual conditions and hence that it might be "legal" to fly in areas where icing was forecast if someone had previously deigned to enter that area and also to transmit a no-icing PIREP.

The Board upheld a 15-day suspension of the pilot's airman's certificate, ruling:


[A] prefatory remark is in order concerning the phrase "known icing conditions," in which respondent was alleged to have flown. We do not construe the adjective "known" to mean that there must be a near-certainty that icing will occur, such as might be established by pilot reports. Rather, we take the entire phrase to mean that icing conditions are being reported or forecast in reports which are known to a pilot or of which he should reasonably be aware.

For years following the Bowen decision, Part 91 pilots belabored under the misapprehension that it was "legal" to fly in areas where icing was merely a forecast event if they had received actual pilot reports reflecting the absence of ice. That misconception was shattered in 1993 when the Board issued its decision in the Groszer case.

In Groszer, a private pilot carrying one passenger crash-landed a Beechcraft Debonair short of the runway at Timmerman Field in Milwaukee, Wis. He had encountered icing in an area covered by a SIGMET for occasional, moderate to severe icing. In denying the pilot's appeal, the Board rejected his argument that PIREPs of no-icing superseded the icing forecasts. The Board stated:


Respondent argues that he did not take off in known icing conditions. He believes that, despite the SIGMET, he was entitled to rely on those 3 of 4 PIREPs that indicated no icing at the altitude and along the route he planned. We cannot agree. It is not within [a pilot's] discretion to pick and choose between the SIGMET and anecdotal PIREPs. ... While PIREPs are valuable in planning (and are used in developing the SIGMETs), they are only one factor to consider. We, thus, do not agree with respondent's claim that a pilot report will establish the absence of icing with "near certainty."

The pilot was found to have operated his aircraft in contravention of its operating limitations and in a careless or reckless manner and, based on those findings, his private pilot certificate was suspended for 180 days.