135 De-icing, what exactly has to be approved

nibake

Powder hound
Let's say there is a 135 operator who does not have an approved deicing system. In this case the only way to be legal when "[contamination] may be reasonably expected to adhere" would be an outside check no more than 5 minutes prior to takeoff. So far so good.

135.227(a) "No pilot may take off an aircraft that has frost, ice, or snow adhering to ..."

So let's say the pic lands and finds ice adhering to the wing. In this case, let's even go so far as to say that new ice is not adhering. Does the lack of having an approved deicing program mean that there the operator is not allowed to deice? What if glycol is sprayed on? What if it's put in a heated hangar? What if I blow on it until it melts?

I'm trying to find the line because the real question here is, just because the operator doesn't have a deicing/anticing program, does that mean that one is not allowed to deice? Can't use holdover tables, I understand that, but can one go out with a glycol sprayer, remove the ice that adhered to the wing, and then confirm compliance with 135.227(a) and even (b)(1) as necessary, and then take off? Or does the lack of op spec approval somehow preclude that sort of thing, and if it does, reference, please?
 

Roger Roger

Paid to sleep, fly for fun
You have 2 standards.
  1. You MUST remove all adhering ice and snow.
  2. You MUST verify within 5 minutes of takeoff that no new ice or snow is accumulating.
You may use ANY method available (glycol, broom, elbow grease, warm hangar) to accomplish 1. You must use a manufacturer or FAA approved method to accomplish 2. For us, our ops manual lists approved methods of accomplishing the pretakeoff check for each aircraft type we operate. Typically it denotes a representative surface visible from the cockpit to check.

While you’re right that we can’t use holdover tables carte blanch like a 121, they are useful. Here’s the example for us: it’s snowing at the base. We have a tank of glycol kept heated to 180°, which we use to douse the plane as we pull out of the hangar if ground icing can be expected. Ops calls and wants to know if we can get out to transport a patient. If we go to the holdover table and see that for our conditions we have 11-17 minutes, that gives us an indication that we can realistically expect to still have a clear contamination check by the time we taxi out and takeoff. On the other hand if the chart shows 3-5 minutes, it’s not realistic to expect that we can still be clean and we’d refuse/postpone the flight.

Similar if we are leaving (International airport) to come home. Airplane sat outside in light snow while dropping off the patient and it’s still light snow. You consult the holdover table and see if you can reasonably expect to still have a good contamination check by the time you take off, if so load up, if not, hold off. You have the FBO deice with heated type I, and verify that the airplane is clean, then get going. Do your approved contamination check before takeoff and if it’s good get out.

Clear as mud?
 
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nibake

Powder hound
Why didn't I get notifications for my own thread, lol.

Regarding the holdover times, we have to do the tactile check within 5 minutes if likely ground icing conditions exist (wrong verbiage, I know).

I'll read the other document. It kinda sounds to me like the POI is taking this farther than it is really meant to go.
 

Roger Roger

Paid to sleep, fly for fun
Why didn't I get notifications for my own thread, lol.

Regarding the holdover times, we have to do the tactile check within 5 minutes if likely ground icing conditions exist (wrong verbiage, I know).
Yes, that’s correct EXCEPT verify that it’s a tactile-our GOM allows a visual. The 208 requires a tactile per the icing AD. But neither of us are flying those crates anymore IIRC.
 

nibake

Powder hound
Ok, according to the GOM, it is hands on and visual during preflight, then hands on with 5 mins of t/o in -FZRA and - FZDZ, otherwise visual suffices.
 
The holdover times for -FZRA are pretty prohibitive anyway. What I’ve found is that when there is -fzra in the TAF and it’s clearly not happening it’s nice not to be held on the ground for a bogus tempo.
"Holdover time for freezing rain" sounds suspiciously like "a little bit pregnant" to me. Maybe I'm just used to a different kind of freezing rain, but for me freezing rain is a binary decision.
 

Roger Roger

Paid to sleep, fly for fun
"Holdover time for freezing rain" sounds suspiciously like "a little bit pregnant" to me. Maybe I'm just used to a different kind of freezing rain, but for me freezing rain is a binary decision.
shrug I didn’t write the tables, dude. It’s there for a reason, I guess.

Like I said, unless you’ve got a deice truck at the hold short line you’re not gonna have a good contamination check by the time you start and taxi, but allowing dispatch in -FZRA and -FZDZ does let you use common sense when the TAF or the Electric Indian is screwy and there’s clearly nothing sticking.
 

Autothrust Blue

The frakkin’ CAG
"Holdover time for freezing rain" sounds suspiciously like "a little bit pregnant" to me. Maybe I'm just used to a different kind of freezing rain, but for me freezing rain is a binary decision.
That's what Type IV is for.

Though, if memory serves, the holdover is still pretty short, and really it's "get sprayed and depart forthwith."

Or go back inside for coffee.
 
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