Perhaps when flying privately you could interpret 'adhering' in such a way that snow on the wings doesn't count and it would be legal. But I'd be extremely surprised that any 703/704 operators have an ops manual and ground ice manual that allows crews to take off with loose snow on the wings.
Jet stream down
Moderators: sky's the limit, sepia, Sulako, lilfssister, North Shore
Re: Jet stream down
As an AvCanada discussion grows longer:
-the probability of 'entitlement' being mentioned, approaches 1
-one will be accused of using bad airmanship
-the probability of 'entitlement' being mentioned, approaches 1
-one will be accused of using bad airmanship
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propfeather
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Re: Jet stream down
Source?
That's not my understanding, but I've been wrong before.
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Old fella
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Re: Jet stream down
Indeed. In my many years ago previous life blasting around in King Airs accumulating 3000+ hrs in every situation possible, snow was always removed from surfaces. It was never leaving anything on the wings that necessitated throwing the nose over for speed to blow contaminate off.airway wrote: ↑Thu Apr 30, 2026 12:26 pmYes, all of this can happen, and you need to be aware of it, but it doesn't appear to be a factor in this accident.digits_ wrote: ↑Thu Apr 30, 2026 11:38 amYes, exactly. Or certain parts of the airframe heat up on the ground once engines are running, melting and then immediately refreezing some snow could happen as well. Not necessarily in critical amounts, but certainly a good reason to remove that 'non-sticking' snow...
"An aircraft take-off performance analysis completed by the TSB laboratory indicated that the occurrence aircraft’s flight performance was not significantly degraded by negative aerodynamic factors related to critical surface contamination. Critical surface contamination therefore did not contribute to the aircraft’s collision with the trees."
It is legal to take off with snow on your wings that you are sure will blow off before rotation. If you think there is any possibility it won't all blow off, get it removed.
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Re: Jet stream down
Maybe someone should quote a regulation. What does adhering mean?propfeather wrote: ↑Thu Apr 30, 2026 1:03 pmSource?
That's not my understanding, but I've been wrong before.
Re: Jet stream down
Means it is sticking to the substrate. It can really only be as simple as that, it either is or it is not loose snow. When it snows while preparing for taking off it can only be common sense to watch that NOTHiNG “adhering” right up until the last chance opportunity to abort before the rotation takes place.
Having checked for the inversion particulars, as CNCP stated; it was notable that there was southerly component of warmer moist air (as high as 40F in south AB) drawing up downslope (almost 3000ft drop from southern AB /northern MT to north AB border/ CYSM) across Alberta and during the hour of this accident there was noticeable southerly component, albeit small, showing up at the surface registering at CFSM airport anemometer (wunderground history 7am jan23 2024). The final report states maximum KIAS reached, though an interpolation (looks like) from measured ads-b groundspeed … if that’s correct? Also states “ hit trees wings level” and further on “ trajectory continued at 300T”. How can it have drifted “.1NM left of centreline” (final report) if investigation showed the impact scar is still near 300T/same as runway heading?
Having checked for the inversion particulars, as CNCP stated; it was notable that there was southerly component of warmer moist air (as high as 40F in south AB) drawing up downslope (almost 3000ft drop from southern AB /northern MT to north AB border/ CYSM) across Alberta and during the hour of this accident there was noticeable southerly component, albeit small, showing up at the surface registering at CFSM airport anemometer (wunderground history 7am jan23 2024). The final report states maximum KIAS reached, though an interpolation (looks like) from measured ads-b groundspeed … if that’s correct? Also states “ hit trees wings level” and further on “ trajectory continued at 300T”. How can it have drifted “.1NM left of centreline” (final report) if investigation showed the impact scar is still near 300T/same as runway heading?
Re: Jet stream down
.
602.11 (1) In this section, critical surfaces means the wings, control surfaces, rotors, propellers, horizontal stabilizers, vertical stabilizers or any other stabilizing surfaces of an aircraft, as well as any other surfaces identified as critical surfaces in the aircraft flight manual.
(2) No person shall conduct or attempt to conduct a take-off in an aircraft that has frost, ice or snow adhering to any of its critical surfaces.
(3) Despite subsection (2), a person may conduct a take-off in an aircraft that has frost caused by cold-soaked fuel adhering to the underside or upper side, or both, of its wings if the take-off is conducted in accordance with the aircraft manufacturer’s instructions for take-off under those conditions.
(4) Where conditions are such that frost, ice or snow may reasonably be expected to adhere to the aircraft, no person shall conduct or attempt to conduct a take-off in an aircraft unless
(a) for aircraft that are not operated under Subpart 5 of Part VII,
(i) the aircraft has been inspected immediately prior to take-off to determine whether any frost, ice or snow is adhering to any of its critical surfaces, or
(ii) the operator has established an aircraft inspection program in accordance with the Operating and Flight Rules Standards, and the dispatch and take-off of the aircraft are in accordance with that program; and
(b) for aircraft that are operated under Subpart 5 of Part VII, the operator has established an aircraft inspection program in accordance with the Operating and Flight Rules Standards, and the dispatch and take-off of the aircraft are in accordance with that program.
(5) The inspection referred to in subparagraph (4)(a)(i) shall be performed by
(a) the pilot-in-command;
(b) a flight crew member of the aircraft who is designated by the pilot-in-command; or
(c) a person, other than a person referred to in paragraph (a) or (b), who
(i) is designated by the operator of the aircraft, and
(ii) has successfully completed training relating to ground and airborne icing operations under Subpart 4 or relating to aircraft surface contamination under Part VII.
(6) Where, before commencing take-off, a crew member of an aircraft observes that there is frost, ice or snow adhering to the wings of the aircraft, the crew member shall immediately report that observation to the pilot-in-command, and the pilot-in-command or a flight crew member designated by the pilot-in-command shall inspect the wings of the aircraft before take-off.
(7) Before an aircraft is de-iced or anti-iced, the pilot-in-command of the aircraft shall ensure that the crew members and passengers are informed of the decision to do so.
SOR/2014-131, s. 13SOR/2020-253, s. 3
One interesting part of this regulation is this:
(i) the aircraft has been inspected immediately prior to take-off to determine whether any frost, ice or snow is adhering to any of its critical surfaces, or
(ii) the operator has established an aircraft inspection program in accordance with the Operating and Flight Rules Standards, and the dispatch and take-off of the aircraft are in accordance with that program; and
(b) for aircraft that are operated under Subpart 5 of Part VII, the operator has established an aircraft inspection program in accordance with the Operating and Flight Rules Standards, and the dispatch and take-off of the aircraft are in accordance with that program.
So it looks like you need an inspection "immediately prior to take-off" unless you are following an established "aircraft inspection program".
.
602.11 (1) In this section, critical surfaces means the wings, control surfaces, rotors, propellers, horizontal stabilizers, vertical stabilizers or any other stabilizing surfaces of an aircraft, as well as any other surfaces identified as critical surfaces in the aircraft flight manual.
(2) No person shall conduct or attempt to conduct a take-off in an aircraft that has frost, ice or snow adhering to any of its critical surfaces.
(3) Despite subsection (2), a person may conduct a take-off in an aircraft that has frost caused by cold-soaked fuel adhering to the underside or upper side, or both, of its wings if the take-off is conducted in accordance with the aircraft manufacturer’s instructions for take-off under those conditions.
(4) Where conditions are such that frost, ice or snow may reasonably be expected to adhere to the aircraft, no person shall conduct or attempt to conduct a take-off in an aircraft unless
(a) for aircraft that are not operated under Subpart 5 of Part VII,
(i) the aircraft has been inspected immediately prior to take-off to determine whether any frost, ice or snow is adhering to any of its critical surfaces, or
(ii) the operator has established an aircraft inspection program in accordance with the Operating and Flight Rules Standards, and the dispatch and take-off of the aircraft are in accordance with that program; and
(b) for aircraft that are operated under Subpart 5 of Part VII, the operator has established an aircraft inspection program in accordance with the Operating and Flight Rules Standards, and the dispatch and take-off of the aircraft are in accordance with that program.
(5) The inspection referred to in subparagraph (4)(a)(i) shall be performed by
(a) the pilot-in-command;
(b) a flight crew member of the aircraft who is designated by the pilot-in-command; or
(c) a person, other than a person referred to in paragraph (a) or (b), who
(i) is designated by the operator of the aircraft, and
(ii) has successfully completed training relating to ground and airborne icing operations under Subpart 4 or relating to aircraft surface contamination under Part VII.
(6) Where, before commencing take-off, a crew member of an aircraft observes that there is frost, ice or snow adhering to the wings of the aircraft, the crew member shall immediately report that observation to the pilot-in-command, and the pilot-in-command or a flight crew member designated by the pilot-in-command shall inspect the wings of the aircraft before take-off.
(7) Before an aircraft is de-iced or anti-iced, the pilot-in-command of the aircraft shall ensure that the crew members and passengers are informed of the decision to do so.
SOR/2014-131, s. 13SOR/2020-253, s. 3
One interesting part of this regulation is this:
(i) the aircraft has been inspected immediately prior to take-off to determine whether any frost, ice or snow is adhering to any of its critical surfaces, or
(ii) the operator has established an aircraft inspection program in accordance with the Operating and Flight Rules Standards, and the dispatch and take-off of the aircraft are in accordance with that program; and
(b) for aircraft that are operated under Subpart 5 of Part VII, the operator has established an aircraft inspection program in accordance with the Operating and Flight Rules Standards, and the dispatch and take-off of the aircraft are in accordance with that program.
So it looks like you need an inspection "immediately prior to take-off" unless you are following an established "aircraft inspection program".
.
Re: Jet stream down
For us that basically means, we can inspect from the cabin to make sure the anti-ice fluid has not failed just prior to taking the runway for takeoff. We can do this under certain circumstances, if we have a lower and an upper HOT, after the lower has passed we can extend five minutes at a time per inspection of the fluid up to the upper limit.airway wrote: ↑Fri May 01, 2026 12:55 pm .
602.11 (1) In this section, critical surfaces means the wings, control surfaces, rotors, propellers, horizontal stabilizers, vertical stabilizers or any other stabilizing surfaces of an aircraft, as well as any other surfaces identified as critical surfaces in the aircraft flight manual.
(2) No person shall conduct or attempt to conduct a take-off in an aircraft that has frost, ice or snow adhering to any of its critical surfaces.
(3) Despite subsection (2), a person may conduct a take-off in an aircraft that has frost caused by cold-soaked fuel adhering to the underside or upper side, or both, of its wings if the take-off is conducted in accordance with the aircraft manufacturer’s instructions for take-off under those conditions.
(4) Where conditions are such that frost, ice or snow may reasonably be expected to adhere to the aircraft, no person shall conduct or attempt to conduct a take-off in an aircraft unless
(a) for aircraft that are not operated under Subpart 5 of Part VII,
(i) the aircraft has been inspected immediately prior to take-off to determine whether any frost, ice or snow is adhering to any of its critical surfaces, or
(ii) the operator has established an aircraft inspection program in accordance with the Operating and Flight Rules Standards, and the dispatch and take-off of the aircraft are in accordance with that program; and
(b) for aircraft that are operated under Subpart 5 of Part VII, the operator has established an aircraft inspection program in accordance with the Operating and Flight Rules Standards, and the dispatch and take-off of the aircraft are in accordance with that program.
(5) The inspection referred to in subparagraph (4)(a)(i) shall be performed by
(a) the pilot-in-command;
(b) a flight crew member of the aircraft who is designated by the pilot-in-command; or
(c) a person, other than a person referred to in paragraph (a) or (b), who
(i) is designated by the operator of the aircraft, and
(ii) has successfully completed training relating to ground and airborne icing operations under Subpart 4 or relating to aircraft surface contamination under Part VII.
(6) Where, before commencing take-off, a crew member of an aircraft observes that there is frost, ice or snow adhering to the wings of the aircraft, the crew member shall immediately report that observation to the pilot-in-command, and the pilot-in-command or a flight crew member designated by the pilot-in-command shall inspect the wings of the aircraft before take-off.
(7) Before an aircraft is de-iced or anti-iced, the pilot-in-command of the aircraft shall ensure that the crew members and passengers are informed of the decision to do so.
SOR/2014-131, s. 13SOR/2020-253, s. 3
One interesting part of this regulation is this:
(i) the aircraft has been inspected immediately prior to take-off to determine whether any frost, ice or snow is adhering to any of its critical surfaces, or
(ii) the operator has established an aircraft inspection program in accordance with the Operating and Flight Rules Standards, and the dispatch and take-off of the aircraft are in accordance with that program; and
(b) for aircraft that are operated under Subpart 5 of Part VII, the operator has established an aircraft inspection program in accordance with the Operating and Flight Rules Standards, and the dispatch and take-off of the aircraft are in accordance with that program.
So it looks like you need an inspection "immediately prior to take-off" unless you are following an established "aircraft inspection program".
.
It does not mean we look at the wing just before rotation to make sure it has blown off, can barely see the wing tip from the cockpit of the RJ, I suspect most 705 aircraft are like that.
Re: Jet stream down
With the 20min in-hangar cold soaking requested by the Captain, and an encore 15min added by ground crew, was due-diligence that new snow stays loose without the de-icing equipment available.
Had read early on that ground crew also assisted the Captain with the pre-departure tactile-inspections in addition to his last second double-checking for non-adherence (Aviation Safety narrative)
For the readers added assurance here that warm fuel affects were not in play — as an unspecified amount of much-lower temped/“minus-20c” fuel was used in topping up — we would still have to calculate all fuel temps/volumes involved (including residual in-wing fuel overnighting in hangar) to verify wetwing fuel temp average stayed below precip freezing point, so no later softening of any snow-particles resting on that wing-skin as is seen laying loose per pax photo (report) about that same time. eg:How much hangared/warmer fuel remaining prior to filling the rest-of-the way to max-full “3200lbs” using outside “-20” fuel stock ?
Had read early on that ground crew also assisted the Captain with the pre-departure tactile-inspections in addition to his last second double-checking for non-adherence (Aviation Safety narrative)
For the readers added assurance here that warm fuel affects were not in play — as an unspecified amount of much-lower temped/“minus-20c” fuel was used in topping up — we would still have to calculate all fuel temps/volumes involved (including residual in-wing fuel overnighting in hangar) to verify wetwing fuel temp average stayed below precip freezing point, so no later softening of any snow-particles resting on that wing-skin as is seen laying loose per pax photo (report) about that same time. eg:How much hangared/warmer fuel remaining prior to filling the rest-of-the way to max-full “3200lbs” using outside “-20” fuel stock ?
