yy - Cold Weather Flashcards
Describe procedures, limitations and techniques.
You are flying to LSZH. It is snowing, with an OAT of -10, and SEV ICE is reported on approach. RWY in use is 34, but the wind is calm. Attention to the following:
- RWY 34 requires a GA gradient of 5%.
- LW is 375.
- LDPA gives 9.2% of GA gradient, with “ice accretion” selected.
What are your thoughts?
[Technique]
7% degradation of GA gradient must be taken into account due ice accretion (reference below), which results in an GA gradient (APP CLB GRD) of 2.2%, way below 5%. Hence:
- Has “CONF 3” been selected, instead of “CONF FULL (STD)”?
“CONF 3” improves the GA gradient by 0.6%, resulting in an GA gradient of 2.8%. - Is there other RWY with a better GA gradient requirement?
Yes. RWY 14 uses standard GA gradient (2.7%).
Running the LDPA for RWY 14 gives good results (green figures).
So, selecting RWY 14 would be the right decision.
[FCOM/PER/LND/GEN - Severe Icing]
The OIS does not take into account severe icing conditions.
Therefore, the flight crew must manually decrease the approach climb limiting weight by 7 % if:
- Icing conditions are predicted during the flight
- The Total Air Temperature (TAT) is less than 10 °C
- There is a significant ice accretion on the non-heated structure.
[PER/LND/LCF/OCD – Outside CONDs]
A/ICE:
One of the following settings can be selected from the A/ICE drop-down list:
- Off
- *ENG only
- ENG & Wing
- **Ice Accretion.
*ENG only: the FADEC compensates to a large extent the THR loss due to “ENG only” A/ICE.
**Ice Accretion: when Ice Accretion is selected on the A/ICE drop-down list, the SPD Increment in VAPP due to the Ice-Accretion (ΔVICE ACCR) is always equal to 0 kt. Moreover, LDG PERF does not take into account the loss of GA Gradient due to Ice Accretion.
When can you determine a condition of Ice Accretion?
[DSC/30/10/10 – Visual Ice Indicators]
The two Visual Ice Indicators outside the ACFT, between the two windshields, provide evidence of ice accretion.
P.n.: hence, whenever ice is visible on the indicators, consider Ice Accretion.
[Technique]
Another way I would personally elect to determine the presence of Ice Accretion would be the triggering of the ECAM A-ICE SEVERE ICE DETECTED. Nevertheless bear in mind the difference: A-ICE ICE DETECTED vs. A-ICE SEVERE ICE DETECTED
A-ICE ICE DETECTED:
Ice builds up on any probe + ENG A/ICE off
A-ICE SEVERE ICE DETECTED:
Ice builds up 7x on the same probe + WING A/ICE off
What’s the definition of “icing conditions”?
[FCOM/GEN - Definitions - Icing Conditions]
- OAT (on ground) or TAT (airborne) ≤ 10⁰C, and visible moisture is present (fog with VIS < 1 sm/1600m).
- OAT ≤ 10⁰C, and maneuvering on TWYs/ramp with “ISSS” (Ice, Snow, Slush or Standing water).
What’s the triggering condition to set the PROBE & WINDOW HEAT pb to on, who does it, and when?
- Rainy conditions and Icing conditions.
- The CM2 does.
- During rainy conditions, set to on for 2 min during glareshield check in case of an out of tolerance altitude indication between ISIS and PFD.
- For Icing conditions, set to on during the Preliminary CKPT PREP (“POTATO” phase)
[FCOM/GEN/GMAI - CKPT PREP]
Clarification of the actions to follow in rainy conditions in case of an out of tolerance altitude indication between ISIS and PFD.
[FCOM/PRO/NOR/SUP/SUP-ADVWXR - DURING PRELIMINARY COCKPIT PREPARATION]
PROBE & WINDOW HEAT pb ……… ON (CM2)
When no engine is started, window heating operates when the PROBE/WINDOW HEAT pb-sw is set to ON.
You are taxiing on a contaminated TWY, and THR application is required. How would you do it?
[FCTM/PR/NP/SOP/100/100-4]
ON TAXIWAY PLUS PAVED SHOULDERS LESS THAN 36 M WIDE OR ON CONTAMINATED TAXIWAYS
On taxiways plus paved shoulders less than 36 m wide OR if the taxiway pavement is contaminated, both the inner and the outer engines are above non-stabilized surface. In this configuration, the flight crew should prefer the use of the outer engines, if additional thrust is needed (uphill taxiway for example).
The flight crew should maintain the inner engines at idle thrust in order to prevent the engines from ingesting foreign objects. The outer engines are high enough to prevent the risk of ingesting foreign objects at taxi thrust.
Which RWYCC should the pilots use for “Specially Prepared Winter Runway”?
[FCTM/PR/NP/SOP/160]
LANDING PERFORMANCE
SPECIALLY PREPARED WINTER RUNWAY
When this type of report is applicable, the flight crew may consider a RWYCC of 4, if permitted by the operator policy.
What’s necessary for the FLS beam to be corrected for cold temperature?
[FCTM/PR/NP/SOP/190]
COLD WEATHER OPERATIONS
FLS BEAM
The virtual FLS beam is corrected for temperature below ISA due to the ground temperature entered in the APPR panel of the FMS ACTIVE/PERF page.
The FMS trajectory is not corrected for temperature below ISA. This may lead to low ISA for the non-superposition of the FMS trajectory to the FLS beam.
When the F-G/S mode engages, the FMS trajectory (green) moves toward the FLS beam trajectory (magenta).
The altitude corrections for cold weather operation should still be applied:
- During approach, before being established on the F-G/S beam (p.n. for instance, at the platform altitude)
- When the FLS capability is F-APP+RAW or RAW ONLY, for the altitude/distance check
- On the value of the minima entered in the FMS.
[FCTM/PR/NP/SP/10/10-1]
IN FLIGHT
APPROACH
FLS CONSIDERATION
Since the FLS provides low temperature compensated guidance, FLS vertical guidance can be used, regardless of the charted minimum temperature.
When flying an FLS in Cold WX, what altitude corrections should still be applied?
[FCTM/PR/NP/SOP/190]
COLD WEATHER OPERATIONS
FLS BEAM
The virtual FLS beam is corrected for temperature below ISA due to the ground temperature entered in the APPR panel of the FMS ACTIVE/PERF page.
The FMS trajectory is not corrected for temperature below ISA. This may lead to low ISA for the non-superposition of the FMS trajectory to the FLS beam.
When the F-G/S mode engages, the FMS trajectory (green) moves toward the FLS beam trajectory (magenta).
The altitude corrections for cold weather operation should still be applied:
- During approach, before being established on the F-G/S beam (p.n. for instance, at the platform altitude)
- When the FLS capability is F-APP+RAW or RAW ONLY, for the altitude/distance check
- On the value of the minima entered in the FMS.
[FCTM/PR/NP/SP/10/10-1]
IN FLIGHT
APPROACH
FLS CONSIDERATION
Since the FLS provides low temperature compensated guidance, FLS vertical guidance can be used, regardless of the charted minimum temperature.
When flying an FLS APP, is the Minimum Temperature depicted on the chart a limitation for the FLS APP?
[FCTM/PR/NP/SOP/190]
COLD WEATHER OPERATIONS
FLS BEAM
The virtual FLS beam is corrected for temperature below ISA due to the ground temperature entered in the APPR panel of the FMS ACTIVE/PERF page.
The FMS trajectory is not corrected for temperature below ISA. This may lead to low ISA for the non-superposition of the FMS trajectory to the FLS beam.
When the F-G/S mode engages, the FMS trajectory (green) moves toward the FLS beam trajectory (magenta).
The altitude corrections for cold weather operation should still be applied:
- During approach, before being established on the F-G/S beam (p.n. for instance, at the platform altitude)
- When the FLS capability is F-APP+RAW or RAW ONLY, for the altitude/distance check
- On the value of the minima entered in the FMS.
[FCTM/PR/NP/SP/10/10-1]
IN FLIGHT
APPROACH
FLS CONSIDERATION
Since the FLS provides low temperature compensated guidance, FLS vertical guidance can be used, regardless of the charted minimum temperature.
WHEN DOES THE FLIGHT CREW HAVE TO CORRECT THE ALTITUDE?
[OMC 10.4.1 General – Cold Temperature Altitude Corrections]
An altitude correction due to cold temperature is not needed for the following conditions:
- While under ATC radar vectors,
- When maintaining an ATC assigned flight level (FL),
- When the reported aerodrome temperature is above 0°C,
- When the ISA temperature deviation at the applicable minimum altitude is less than stated in OM-C 10.4.1.1 (en-route), or
- When the aerodrome temperature is at or above the minimum published temperature for the procedure being flown (refer to A380 below).
A380
If FLS available, regardless of the charted temperature limits, use (LNAV/VNAV Approach Minima if available, or LNAV Approach Minima) and apply cold temperature altitude corrections according OM-C 10.4.1.2.
If FLS not available, Use LNAV Approach Minima, and apply cold temperature altitude corrections according OM-C 10.4.1.2.
[OMC 10.4.1.2 ALT CORR - Approach]
Apply the altitude correction table when needed:
- Apply corrections to all published minimum approach altitudes as per the table. Advise ATC of the corrections.
Note:
Do not apply corrections to the FMC/FCU coded altitudes of less than 100 feet.
P.n.: apply the ALT CORR on the FCU, not on the FMS (except for the MDA/DA , and MISAP ALT, if below corrected MSA)
- Apply corrections to the published missed approach altitude only when below the temperature corrected Minimum Safe Altitude (MSA), and with prior ATC approval.
- MDA/DA settings shall be set at the corrected minimum altitudes for approach.
[FCTM/PR/NP/SP/10/10-1]
IN FLIGHT
APPROACH
WHEN DOES THE FLIGHT CREW HAVE TO CORRECT THE ALTITUDE?
Even if the aircraft is radar vectored, the flight crew must apply altitude correction for the following published altitude:
- Minimum En route Altitude (MEA) and Minimum Safe Altitude (MSA)
- Altitudes constraints during the Approach or Missed Approach
- Procedure turn altitude (as applicable)
- Final Approach Fix (FAF) and Final Approach Point (FAP) altitude
- Step-down altitude(s) during approach without vertical guidance
- Altitudes checks during final approach (check altitude versus distance or outer marker check altitude, as applicable)
- Barometric minima, i.e. MDA(H) or DA(H) for CAT I ILS approach.
WHEN DOES THE FLIGHT CREW HAVE NOT TO CORRECT THE ALTITUDE?
Usually, when the aircraft is radar vectored, the flight crew must not correct the altitude provided by the ATC. The air traffic controller has the responsibility to provide altitudes or flight levels corrected to take into account the minimum clearance with the terrain. However, the flight crew must confirm this responsibility with the ATS in charge.
Note:
When an aircraft is radar vectored, the interception altitude of an ILS should only be corrected by the flight crew if it is the minimum interception altitude published.
Does the FPA required any correction due cold temperature?
Yes. A slight increment is necessary to fly in Cold Temperature conditions.
[FCTM/PR/NP/SP/10/10-1]
IN FLIGHT
APPROACH
FPA CORRECTION
In low temperature condition, the barometric altitude displayed in the cockpit is higher than the physical altitude of the aircraft. The selected FPA displayed in the cockpit uses the same references as the altitude, barometric references. Therefore, the selected FPA displayed in the cockpit is higher than the geometric one. If the flight crew needs to fly a FPA, the flight crew should increase slightly the selected FPA value in the cockpit to take into account low temperature effect to fly the desired geometric FPA.
In any case, the check “altitude (corrected in temperature) versus distance” remains the reference. The flight crew will adjust accordingly the selected FPA.
What’s the impact of the REVs during crosswind LDGs?
[FCTM/PR/NP/SOP/220]
ROLLOUT
CROSSWIND CONDITIONS
The reversers destabilize the airflow around the rudder and therefore, decrease the rudder efficiency. In addition, they create a side force in the case of a remaining crab angle, which increases the lateral skidding tendency of the aircraft. This adverse effect is noticeable on contaminated runways with crosswind. If a lateral control problem occurs during high crosswind landing, the flight crew should consider to set the reverser levers back to REV IDLE.
What should the crew have in mind when taxing on contaminated TWYs?
[FCTM/PR/NP/SP/10/10-1]
TAXI-OUT
On contaminated taxiways, the taxiing speed should be as low as possible, and any action that could distract the flight crew during the taxi should be delayed until the aircraft is stopped.
What’s the limitation of TKOF THR on contaminated RWYs?
[FCTM/PR/NP/SP/10/10-1]
TAKEOFF PERFORMANCE
When taking off on contaminated runways, it is not permitted to use FLEX thrust.
What’s the target SAT during DES to turn on the ENG A/ICE on?
Any.
[FCOM/PRO/NOR/SUP/SUP-ADVWXR]
FLIGHT IN ICING CONDITIONS
ENGINE ANTI-ICE
Engine anti-ice must be ON during all ground and flight operations, when icing conditions exist or are anticipated, except during climb and cruise when the SAT is below –40 °C.
Engine anti-ice must be ON before and during a descent in icing conditions, even if the SAT is below –40 °C.
