Originally Posted by
autoflight
Early morning daylight, OAT was -24C. During drive to stand-off parking, no ice on vehicles, baggage trolleys or aerobridges. Pre-flight walkaround check: no ice visible on fuselage, wings, tail or fight controls. Checked upper wing surfaces from pax widows. Considering the consequences of ice, rather than the chance of ice, I also opened a back door and leaned out a little to cheek the rear stabiliser upper surfaces one, side of the fin and control surfaces. No ice.
Seemed most unlikely that a check from the other back doorway was necessary, but did it anyway. Significant amount of clear ice made de-icing essential.
There has to be a lesson there.
Hi,
Thanks for this input; in the northern hemisphere we will shortly enter the winter season and all chances to review some cold weather topics are always welcomed!
May I ask how long had the airplane been on the ground for and how much fuel was there remaining in the wing tanks? Chances are that the skin temperature was around the freezing point with some high levels of humidity and/or a relatively high amount of fuel was left in the wing tanks (tankering sector the night before?) and/or some freezing precipitation occurred during the night. All aspects that are very likely to lead to the formation of clear ice.
I remember we used to fly to a destination in Eastern Europe at night in winter time with tankering fuel; the airplane would stay on the ground for 6-8 hours or so and leave again early morning. The night was spent with temperatures similar to what You describe. Needless to say we had many occurrences of clear ice formation always spotted by the local (well acquainted) engineering teams prior to the crew arrival and which would have been impossibile to detect if not from a tactile check.
