De-ice/anti-ice

Question 1

We can do both de-icing and anti-icing in a one- or two-step process.
When should we use one or the other process, on what does that depend?

Answer 1

It depends on:
- weather conditions
- available equipment
- available fluids
- desired hold-over time (HoT)
But always use a two- step process as it cleans away fluid from previous flights

(NOR OM A 8.2-35)

Question 2

Will the airport always report the Braking Action of the taxiways?

Answer 2

No, they only report when the BA is POOR or less.
( Chief Pilot Info, winter edition, 2024)

Question 3

With how much meter will the landing distance increase on a slippery runway when we increase the speed with 10kts?

Answer 3

It will increase with 100 m on a dry runway and almost twice that much on a slippery runway.

Question 4

When is snow or ice allowed to build up on the fan spinner or fan blades?

Answer 4

When it has been accumulating during approach or taxi in, and when the fan is free to rotate and when it will be removed using the ice shedding procedure during taxi out.

Question 5

Before de-icing, about what do you need to inform the ground crew?

Answer 5

• The fuel temp. if it’s lower than the OAT as this may affect the % of water used in the deicing mixture.
• If the APU is running because ingesting de-icing fluid can cause fumes and odours to enter the aircraft.

Question 6

When should we put on the PROBE HEAT switches in Icing Conditions?

Answer 6

The F/O needs to switch them ON after completing the normal Preflight Procedure.

Question 7

What can we do when the COWL VALVE OPEN lights remain illuminated with engines in IDLE before taxi?

Answer 7

Verify APU bleed air switch is in the OFF position, ISOLATION VALVE in AUTO, then when the area around the aircraft is clear increase the thrust slightly up to a max of 30% N1 (same for 737NG and 737MAX)

Question 8

After De- Anti-Icing, when should we taxi with the flaps up and what should we do as a reminder for that?

Answer 8

• When the taxi route is through slush or standing water in low temperatures, or if precipitation is falling with temperatures below freezing.
• Place the checklist on the control column clip board.

Question 9

In cold weather operations, what should be the minimum temperature of the engine oil before setting T/O thrust on a 737MAX?

Answer 9

31°C

Question 10

Can we use reverse thrust if needed when we taxi on a slippery taxi way?

Answer 10

Yes, we can use idle reverse thrust momentary.

Question 11

When should we do an engine run up?

Answer 11

In icing conditions with an OAT of 3°C or below.

Question 12

How should we do an engine run up on a B737NG and B737MAX?

Answer 12

B737NG: 70% N1 thrust for 30 seconds.
B737MAX: 50% N1 for minimum 5 seconds.

Question 13

What is the company procedure for using wing anti ice? (Until which FL can we use it?

Answer 13

Company Procedure: Wing anti is not recommended above FL300
Using wing anti ice above approx FL350 may cause bleed trip off and possible loss of cabin pressure.

Question 14

Boeing QRH PI Advisory data reference landing distance is based on which speed?

Answer 14

Threshold crossing speed of only Vref.

Question 15

How to land with crosswind on a very slippery runway?

Answer 15

Touch down without removing the crab angle reduces drift. Autospoilers and auto brake operate sooner when both main gear touch down simultaneously.

Question 16

What should we do when the aircraft starts to skid sideways on a slippery runway?

Answer 16

• Release the brakes
• Reduce reverse thrust to idle
• Regain control of aircraft and correct toward RWY centreline
• Apply max braking and use symmetrical reverse thrust

Question 17

Can we retract flaps if we land/taxi through slush after landing?

Answer 17

Do not retract beyond flaps 15.

Question 18

Which BA should we use to calculate landing distance when different BA are measured?

Answer 18

Use the lowest BA for the whole runway.

Question 19

Can we land if the landing performance calculation is near limits on BOTH crosswind AND runway length?

Answer 19

It is not recommended unless the CMDR can determine that good visibility and displaced threshold permits landing early within the touchdown zone.

Question 20

What can we do if the RWYCC is not given?

Answer 20

Use RCAM (RWY Condition Assessment Matrix) It is a table that gives you the RWYCC from 6 to 1 based on the contamination on the runway and OAT. Lower the value if the OAT is close to 0°C and the dewpoint spread is less than 3°C.

Question 21

Do we need to use Engine anti ice when the weather is good (no precipitation, CAVOK,..) but the RWY and taxiways are wet?

Answer 21

No, we don’t need anti ice, only if there is standing water.

Question 22

Which are the 4 conditions we need to meet so CSFF is allowed on the UPPER wing surfaces?

Answer 22

1. Only in the CSFF area and no snow, ice or frost on the leading edges or control surfaces.
2. OAT is 4°C or more.
3. Tank fuel temperature is at or above -16°C.
4. No precipitation or visible moisture (fog with less than 1 mile visibility)

Question 23

When is Takeoff with CSFF on the LOWER wing surfaces allowable?

Answer 23

1. OAT is at or above +4°C
2. There is no precipitation or visi‭ble moisture (rain, snow, drizzle,​ ​‬
   or fog with less than 1 mile visibility)‭​‬
3. Tank fuel temperature is at or above -16°C
4. All leading edge devices, all control surfaces, tab surfaces, ‭​‬winglet surfaces, and control surface balance​ panel cavities ‭​‬must be​ free of snow, ice​ and frost.‭​‬
   If all of the above condit‭ions are not met, takeoff with light coatings ​‬of frost, up to 1/8 inch (3 mm) in‭​ thickness, on lower wing surfaces ​‬due to cold fuel is allowable; however,​ all leading edge​ devices, all ‭​‬control surfaces, tab surfaces, wi‭nglet surfaces and control surface ​‬balance panel cavities must be free of snow, ice​ and frost. If the frost ‭​‬
   on the lower surface​ is​ greater than ‭1/8 inch (3 mm) in thickness, all ​‬snow, ice and frost on the wings must be removed using appropriate ‭​‬deicing/anti-icing procedures.‭​‬

Question 24

‭How long is as SNOWTAM​ valid?‬

Answer 24

8 hours.‬

Question 25

‭What does it mean when there is no SNOWTAM issued?‬
‭

Answer 25

That the runway is either DRY​ or ​‬the airport is closed.