anti ice used
we can use anti-ice if icing conditions exist or when we see a message the ice is detected up to touch the runways?
or at an altitude of 1000-500AGL, in case if icing conditions exist or when we see a message the ice is detected, we must switch to icing level 2 up to touch the runways ?
or all anti ice should be turned off at altitude of 1000-500AGL?
Comments
You can use the Anti Ice System (Airframe Anti Ice and Propeller De Icing) until landing, if required. The INCREASE REF speed switch is set to Off below 1000 ft AGL. Here under icing condition the relevant Speeds are provided again with a surcharge of 20 Kts.
So if the Increase Ref Speed switch is set to off below 1000 AGL but the airframe and propellor anti ice systems are still in use on final approach, do I still add 20kts to the Vref? If yes, why turn off the Increase Ref switch, if no, why have an Increase Ref Speed switch at all? Hope you can help me with my confusion.
In the range above 1000 feet AGL, the switch is used in the case of the ice detection message, and increases the REF speed for the stall protection system (SPS) by about 15 Kts, since the Dash with possibly iced wings rather goes into the stall. You can watch that in cruising flight if you do not accelerate at the TOC, but approach the minimum operating speed. If this is e.g. at 125 Kts, this is increased to 140 Kts what you see on the PFD. The Stall Protection will be active, including around 6 Kts Margin, at 146. But this also has consequences, e.g. Autopilot Off, Stick Shaker and Stick Pusher.
For the takeoff and the landing up to and below 1000 ft AGL you set the increased reference speed of 20 Kts as a marker and have this as a guide. Why the switch is not taken below 1000 ft at the takeoff, I can perhaps explain about the AoA, which is indeed used for internal calculation of the stall protection system (SPS) (in addition to some other factors), and which in the first segment after the Takeoff is still quite big. When landing I can only assume that it should prevent unwanted consequences, such as switching off the AP by an appealing. In these two phases, the crew has just Speed Marker as a guide.
I have a fcom, but there are no instructions in it to turn off the INCR REF SPEEDS switch at a height1000ft.
In addition, there is described the procedure:
-Action Once the Aircraft is Aerodynamically Clean-
-AIRFRAME MODE SELECT ............................................................OFF
-REF SPEEDS switch .......................................................................OFF
-Check INCR REF SPEED disappears from ED
MINIMUM AIRSPEED............... VREF FOR FLAP SETTING +10 kts for
manoeuvring
and
The PROP Selector should be left ON and the ENGINE INTAKE by-pass doors left at
OPN/HTR if there is visible moisture present with a SAT of 5°C or below
But this procedure should be performed only in case of complete absence of ice, if ice remains on the surface, this procedure should not perform.
Perhaps you have a new document fcom where it is described in more detail?
For the takeoff, this is to read in the Majestics documents. INDR REF SPEED Switch only on above 1000 ft AGL. Unfortunately I only derived the whole thing for the landing.
Do you have your FCOM from a public source as a download? Unfortunately, one does not find really good documents.
Yes, but nowhere is it written about when to turn off REF SPEED;)
I'm not sure whether can upload this FCOM without asking for copyright;(
Everything related to the anti-ice procedures I will try to upload in the screenshots;)
At Boeing, there is something that is all connected with the conduct of the flight in the FCTM, but whether that is the case with the Dash. Obviously, there are many questions that arise with this outstanding implementation!
Normally when the surface temperature is 5°C/41°F or below and there is the presence of visible precipitation icing systems are kept on for landings and takeoffs, this includes activating the INCR REF SPEED switch......approach speeds should also be increased by 20 knots
we have another question, whether the whole anti-ice system should be turned off when landing at a height of about 1000 feet if icing conditions exist?
P.S and in fcom other information on icing conditions: if the temperature 10(not 5)and below + there is visible moisture or fog.
From MALEV:
2.6.2 TAKEOFF IN ICING CONDITION At 1000 feet above aerodrome elevation select INCR REF SPEED switch to INCR after having accelerated to minimum V2 + 20 kts (Bug Speed). - Check INCR REF SPEEDS advisory appears on ED.
Caution:
If airspeed is not increased before INCR REF SPEED switch is selected to INCR, stall warning may occur. Correct VFRI and VCLIMB speeds by adding 20 kts in icing condition according to speed booklet.
2.8.4 APPROACH IN ICING CONDITIONS Maintain minimum VAPPR corrected in icing conditions clean configuration. Make a normal approach with corrected VREF If control wheel forces become irregular after setting landing flap: • Retract flap to a lower setting • Boots should remain in AUTO FAST mode during approach and landing in icing conditions • Land with Flap 15° if possible
I know that MALEV does not exist anymore but I think these procedures should be still valid now.
JP
P.S and in fcom other information on icing conditions: if the temperature 10(not 5)and below + there is visible moisture or fog.
You are correct ...it is 10 deg. I am thinking of another type aircraft.
But may i ask,If that really has any effect at all whether you use it or not. Or questioned another way round, is icing realistically simulated in P3D?
@DCLAN
The aircraft is modeled to simulate icing effects on the air-frame which is driven by the weather from within the SIM, be it default generated weather or an external weather program of choice.
Cheers
Optically i did see that. Meant it more in terms of weight gain and aerodynamics.
The aircraft aerodynamically will undergo a significant impact when flying in icing conditions without using the de-icing mechanisms during flight and in some cases on the ground.
FCOM FLYBE says that landing in icing conditions, uuse Flap 35 for Landing unless CAT II approach or with one engine inoperative, not Flap 15!
And, for clarity, should consider the use of the ENGINE INTAKE by-pass
doors 'tied' to the PROP selector. That is, when conditions dictate that the
PROP selector is to be switched on
are switched to OPN / HTR. When conditions allow PROP selector to be
OFF, the by-pass doors should not be CLOSED. Exceptionally, after
the airframe is still
affected by significant amounts of ice. In such circumstances, despite
having turned the crew off
doors at OPN / HTR.
Furthermore, to avoid confusion, the term ‘Standard Flight’ applies to
conditions where all ice protection switches
PITOT STATIC switches and the WINDSHIELD HEAT selector which will be
On and NORM, respectively) are OFF and the by-pass doors CLOSED.