Take-off Configuration after Type 4

[Pratt X 3]

After spending some time in various de-icing facilities across the country recently, I've noticed something that seems to go against what I had thought was an industry standard. After receiving a Type 4 anti-ice treatment, some aircraft are being configured for take-off (slats/flaps deployed) as soon as the aircraft has been sprayed, during active, freezing/frozen precipitation. Even with a significant taxi still to go, as in more than 5 minutes from the runway. It has always been my understanding that configuring the slats/flaps and moving flight controls/stab trim was done as close as possible to the take-off point to minimize exposure of the unprotected surfaces of the wings from any falling precipitation as well as maintaining effective fluid thickness to allow proper protection to conduct a safe departure. Manufacturer procedures prescribed this concept in their publications by having a separate checklist for such conditions with the configuration done before take-off instead of before taxi in the different types that I have operated. Having now witnessed both ways of doing it, it appears to be a company procedure versus a manufacturer. For example, there was an Airbus A320/321 from one company that left the flaps up until closer to the runway as there was going to be some time before reaching the threshold due to engine runups/ice shedding as well as runway clearing by the plows. However another company with a similar type as well as an A330 from the same company both deployed slats/flaps early with about 15 minutes of exposure to falling frozen precipitation. So why the change from what I thought was an industry standard?

[Chaxterium]

In all the jets I've flown, CRJ-200, Falcon 900, B757, and now the E195-E2, setting the flaps to the take off position was part of the De-icing/Anti-Icing Spray checklist. As in we set the flaps to the take off position before we even leave the de-icing pad.

[Pratt X 3]

Of these different types, did the De-icing/Anti-Icing Spray checklist, which I take was a company-specific document, differ from what the manufacturer published in the AFM, ORM/AOM or QRH? (To be fair, those manufacturer materials can be a bit vague sometimes)

How about this scenario? Nasty night in YYZ; moderate snow falling or maybe it's light freezing rain. Will need to taxi to runway 05 as it is the only one available for departure. Taxiways are covered in slush so it will be a slow taxi once you get going. Holdover will still work but are you still dropping the flaps in the CDF after the type 4 is applied or maybe waiting until closer to the runway to avoid exposing the parts of the wing that didn't get any type 4?

[daedalusx]

Of these different types, did the De-icing/Anti-Icing Spray checklist, which I take was a company-specific document, differ from what the manufacturer published in the AFM, ORM/AOM or QRH? (To be fair, those manufacturer materials can be a bit vague sometimes)

How about this scenario? Nasty night in YYZ; moderate snow falling or maybe it's light freezing rain. Will need to taxi to runway 05 as it is the only one available for departure. Taxiways are covered in slush so it will be a slow taxi once you get going. Holdover will still work but are you still dropping the flaps in the CDF after the type 4 is applied or maybe waiting until closer to the runway to avoid exposing the parts of the wing that didn't get any type 4?

It's usually left to the best judgement of the flight crew. In your case, I would delay configuring.
https://www.boeing.com/commercial/aerom ... 2010_q4/2/

If the taxi route is through ice, snow, slush, or standing water, or if precipitation is falling with temperatures below freezing, taxi out with the flaps up. Taxiing with the flaps extended subjects flaps and flap devices to contamination.

From the Cold Weather SP

If taxi route is through ice, snow, slush or standing water in low temperatures or if precipitation is falling with temperatures below freezing, taxi out with the flaps up. Taxiing with the flaps extended subjects the flaps and flap drives to contamination. Leading edge devices are also susceptible to slush accumulations. If there is snow or ice accumulation on the wing, consider delaying the flight control check until after de-icing/anti-icing is accomplished.

[Col. Panic]

The types I have flown, at least at my current company, have had the suggestion to delay flap deployment in those conditions. The complication is that one must decide when the appropriate time is to deploy, as we cannot complete several items on the before takeoff checklist until the flaps are in the planned takeoff position. The advantage of mechanical or electronic checklists is that you can skip these items, leaving them open until you are ready. There are, however, other checklist items that may not immediately seem related to leaving the flaps up, but your ability to complete them may still be affected. For example, at least one type I flew limited rudder travel on the ground with the flaps up, so you could not complete the control check until flaps were selected.
As always, completing a checklist out of order introduces a threat, which can be mitigated by technology (sensed items that will not complete the electronic checklist until the appropriate control is in the correct position, etc.), but may simply disrupt the normal flow in such a way that other errors may be made.
Thus many will decide to delay the before takeoff checklist until flaps are selected, and try to time this so that the exposure to icing conditions with the unprotected portions of the slats/flaps is minimized. This requires a reasonable estimate of time before you will be able to takeoff, as well as a good estimate of how long it takes to complete the checklist.

[MaxAuto]

The proper way is to delay flap configuration to as close to takeoff s possible. But I think most pilots are afraid they will forget to configure which is why most to pilot to don't wait nto configure. A new procedure on the 737 is to cycle the flaps to 40 then back to zero in icing conditions to check the full range of motion.

[cdnavater]

In all the jets I've flown, CRJ-200, Falcon 900, B757, and now the E195-E2, setting the flaps to the take off position was part of the De-icing/Anti-Icing Spray checklist. As in we set the flaps to the take off position before we even leave the de-icing pad.

Chaterium, where did you fly the CRJ 200?
At Jazz the flaps are near the end of the before take off checklist and this is part of our procedure,

“If the flaps and/or slats require de-icing due to contamination from an approach in icing conditions with freezing precipitation, or operating on contaminated surfaces, extend to 45° for the de-icing procedure. Prior to the application of type II, III, or IV anti-icing fluid select FLAPS back to 0. If anti-ice not required (de-ice only) select flaps to 0 when deicing complete.”

“Upon completion of de-icing/anti-icing, if taxiing in freezing precipitation or on contaminated surface, the flaps shall remain at 0° until takeoff is imminent to prevent contamination of unprotected areas. Select FLAPS for takeoff with the Before-Takeoff check.”

[Chaxterium]

Chaterium, where did you fly the CRJ 200?

Not Jazz. I flew the CRJ200 with two companies and at both lowering the flaps was done prior to starting the taxi in normal ops. For winter ops I'm sure we had a similar procedure as you mentioned where we'd delay setting the flaps until closer to take off but I no longer recall.

[cdnavater]

Chaterium, where did you fly the CRJ 200?

Not Jazz. I flew the CRJ200 with two companies and at both lowering the flaps was done prior to starting the taxi in normal ops. For winter ops I'm sure we had a similar procedure as you mentioned where we'd delay setting the flaps until closer to take off but I no longer recall.

A long time ago we would select flaps during the after start check, it was moved for this reason, it’s best near the end of the before take off, you say holding at flaps at then there are on a couple things to do after you select flaps.

[BigQ]

In YUL yesterday morning, an AT A330 going to unknown destination extended the flaps between type 1 and type 4... They had to ensure all the AEROMAG trucks stopped spraying and moved away from the wings before they extended their flaps and continued with type 4 application. Weather was 1SM RVR 5000 SN at the time.

I've never heard of doing this before, this is new?

[cdnavater]

In YUL yesterday morning, an AT A330 going to unknown destination extended the flaps between type 1 and type 4... They had to ensure all the AEROMAG trucks stopped spraying and moved away from the wings before they extended their flaps and continued with type 4 application. Weather was 1SM RVR 5000 SN at the time.

I've never heard of doing this before, this is new?

That is strange, we are not allowed to put type 4 on our flaps, flaps go out to de-ice with type 1 and are retracted for 4 but I don’t fly a 330 , so I’m curious of anyone else who does.

[goingnowherefast]

There are a different set of HOT charts for flaps/slats extended. If a company's SOP is to utilize that procedure, it is available with published numbers

[Pratt X 3]

The HOT charts for flaps/slats extended can be found in Appendix A of the Transport Canada Holdover Time (HOT) Guidelines. On page A-1 there is a note that states:

These tables are for use when flaps/slats are deployed prior to de/anti-icing. Holdover and allowance times have been adjusted to 76 percent of standard times. Standard holdover and allowance times can be used if flaps and slats are deployed as close to departure as safety allows.

[cdnavater]

The HOT charts for flaps/slats extended can be found in Appendix A of the Transport Canada Holdover Time (HOT) Guidelines. On page A-1 there is a note that states:

These tables are for use when flaps/slats are deployed prior to de/anti-icing. Holdover and allowance times have been adjusted to 76 percent of standard times. Standard holdover and allowance times can be used if flaps and slats are deployed as close to departure as safety allows.

That’s interesting, why would anyone use that method then?
Seems to me, you would use more fluid that is typically charged by volume and it reduces the HOT, I see no logical reason to do this.

[CaptDukeNukem]

The HOT charts for flaps/slats extended can be found in Appendix A of the Transport Canada Holdover Time (HOT) Guidelines. On page A-1 there is a note that states:

These tables are for use when flaps/slats are deployed prior to de/anti-icing. Holdover and allowance times have been adjusted to 76 percent of standard times. Standard holdover and allowance times can be used if flaps and slats are deployed as close to departure as safety allows.

That’s interesting, why would anyone use that method then?
Seems to me, you would use more fluid that is typically charged by volume and it reduces the HOT, I see no logical reason to do this.

Embraer uses flaps up, and trim in range of neutral to full nose down. No config or flight control checks to be performed prior to de-ice/anti-ice.

I think the logic for the config changes for flap settings during the procedure might be the assembly itself, to prevent/remove sticking in the flap/slat tracks, etc.

[Pratt X 3]

After de-ice/anti-ice is completed, when does Embraer suggest the flaps be lowered, the trim set to take-off and the flight control checks performed? Is it part of the de-ice procedure or the before take-off checks?

[RoAF-Mig21]

Stupid question:

Some checks, such as Trims are done before pushback, knowing that we would have to de-ice and no flight control checks are to be done until after de-ice procedure. Why do we do trim checks (rudder, roll and pitch) before we de-ice?

[Pratt X 3]

Stupid answer: Not sure.
Stupid guess: Some manufacturers don't dive too deep into the small details on anything that the legal department doesn't flag while bringing a new aircraft to market. And the things that are flagged are usually due to prior crash investigations and/or lawsuits. Here's my guess; no major thing has been because someone checked the trim before de-icing. There has been such things when aircraft weren't de-iced/anti-iced properly or at all so those procedures were developed.

[pelmet]

Flaps are to be left up during the taxi until close to the runway for takeoff when there is freezing contamination falling(snow/sleet/etc). Then do your four associated things prior to takeoff(which you briefed to remember to do)......have someone visually check the wings(initiate this action with more than enough time for the person to be able to get back to the cockpit as it can take a while is some types), set takeoff flaps, check holdover time, remember to do an engine run.

[BigQ]

Stupid question:

Some checks, such as Trims are done before pushback, knowing that we would have to de-ice and no flight control checks are to be done until after de-ice procedure. Why do we do trim checks (rudder, roll and pitch) before we de-ice?

For the 737, Boeing certified the 757 and 767 to set the trim after turning on the hydraulic pumps, and thus, co-certified the 737 to do the same, even though the system is different.

[CaptDukeNukem]

After de-ice/anti-ice is completed, when does Embraer suggest the flaps be lowered, the trim set to take-off and the flight control checks performed? Is it part of the de-ice procedure or the before take-off checks?

We configure after de-icing is complete prior to taxiing out of the de-ice facility on the embraer

[pelmet]

Stupid question:

Some checks, such as Trims are done before pushback, knowing that we would have to de-ice and no flight control checks are to be done until after de-ice procedure. Why do we do trim checks (rudder, roll and pitch) before we de-ice?

For the 737, Boeing certified the 757 and 767 to set the trim after turning on the hydraulic pumps, and thus, co-certified the 737 to do the same, even though the system is different.

Some jets have a trim position for de-icing. Full nose-down I think it was. Full one way or the other anyways.

[BTD]

For the aircraft I’ve flown, it is usually centred or within the takeoff range. Generally full up or down isn’t good as you will dump all the type 4 off the horizontal stab. Unless it’s an md 80 or something.

Some set position at the gate, and some with the before takeoff checklist after deicing.

I can’t remember specifics for all but that is across the E190,A220,737, and 767

[pelmet]

For the aircraft I’ve flown, it is usually centred or within the takeoff range. Generally full up or down isn’t good as you will dump all the type 4 off the horizontal stab. Unless it’s an md 80 or something.

Some set position at the gate, and some with the before takeoff checklist after deicing.

I can’t remember specifics for all but that is across the E190,A220,737, and 767

I don't think the type 4 is going anywhere. It is pretty sticky stuff. Fascinating to watch it out the passenger window on the takeoff roll.

Then again, when the Boeing guys came a few years ago to impress us with their briefing on the new 777X(and to blame the pilots on the Max crashes - which has partial merit), I asked them about holdover time on folded wings.....they said they were still working on that.

[BTD]

It will definitely run off. Not instantly, but over a couple of mins the coverage won’t be sufficient on flaps and slats if precip is falling. I’ve had to go back to spray because the wind blew off the type 4 well before the high time limit.

Edit to add. I agree that on the horizontal stab there wouldn’t be much runoff. But some types have a specific position for the stab.