Winter Operations
 

I've very little, infact close to none, experience in winter operations.

Would appreciate some constructive advice.

1- If the holdover times are exceeded and if its snowing , are you required to return to the gate ? or just a visual check on wings will suffice?

2- if its raining and temperature are low. What would be the temperature that indicates that a deice/anti-ice is required? same as engine anti-ice criteria ( OAT +10 or lower ) ?

Thank you in advance.

Here are FAA Holdover Tables, which should answer question 2.

http://www.globalspanaviationgroup.com/FAAHOT.pdf

Question 2 is dependent on whether the wing is cold soaked.

About Question 1, I would return to the gate or wherever I could do a "hands on" check. By the time, you go outside and check, you'll need to get de-iced again, anyway.

GF

From what I would consider fairly extensive experience in winter operations 20+ years here in Canada where winter ranges anywhere from a few weeks to 5 months each year. Here is my take and our company SOP.

The holdover tables contain a range of times in each cell for each temperature and precip condition, the lower of these times is the no inspection required holdover time. Provided you do not exceed this time you may depart with no further action required by the crew. If you exceed this lower time in the cell but not the upper limit, a visual inspection of a representative surface on your aircraft (usually the upper surface of the wing visible from the cabin) is required and must be free of contamination before a takeoff is attempted. If the upper time in the cell is exceeded the aircraft must return for additional deicing and/or anti-icing.

Hope that helps.

Dave

In real life you will find that when you try to do the visual inspection, you will probably not be able to see much at all (especially in snow and at night). Then the hold-over time for the prevailing conditions becomes your critical tool in deciding whether to go or not.

If in doubt, get a re-spray. It isn't worth your life to press on.

Read this for starters.

Many thanks guys. :)

If it is raining and temperature say +3°c or below and the fuel temperature is negative (e.g. -10°c) from a cold soak during a previous flight you might get clear ice forming on top of the wings, and it can be hard to tell whether it is iced or only wet. I guess some types may be more prone to this than others.