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A320 question of the day

Every day the home page asks one question from the Knowledge Trainer, the same for everyone. Here is each past day's question, with its answer and the explanation from the FCOM.

Today's question

Navigation & SurveillanceA320ceo only

The AP/FD TCAS mode is flying an RA, and CLEAR OF CONFLICT is announced. In most cases, which vertical mode follows?

  1. ALT, holding the altitude reached at the clear of conflict
  2. OP CLB or OP DES toward the FCU altitude
  3. V/S, leading the aircraft back toward the FCU altitude
  4. The vertical mode that was engaged before the RA
Show the answer

Answer C: V/S, leading the aircraft back toward the FCU altitude

At CLEAR OF CONFLICT, the AP/FD TCAS mode in most cases reverts to V/S mode, with a vertical speed target leading the aircraft toward the FCU selected altitude. If the altitude capture conditions are met, it can revert to an altitude acquire or altitude hold mode.

FCOM DSC-34-SURV-60-10 · AP/FD TCAS

Fire Protection

When the APU FIRE pb is pushed and released, it sends a signal that performs several actions. Which of these is NOT done by the pb itself?

  1. APU fuel low pressure valve closes
  2. APU bleed valve and crossbleed valve close
  3. APU fire extinguisher discharges
  4. APU generator is deactivated
Show the answer

Answer C: APU fire extinguisher discharges

Releasing the APU FIRE pb only arms the squib; the AGENT pb must then be pressed to discharge the bottle. The pb itself shuts the APU down, closes the LP fuel valve and the APU bleed and crossbleed valves, and deactivates the APU generator. On the ground the bottle also discharges automatically 3 s after an APU fire warning, but that comes from the fire detection, not from the pb.

FCOM DSC-26-20-20 · Controls and Indicators / FCOM DSC-26-20-20 · Engines and APU

Landing Gear & Brakes

L/G LGCIU 1+2 FAULT in cruise. What does it mean for the landing?

  1. Normal gear extension, but no ECAM gear indications
  2. Gravity gear extension, with the reversers normal
  3. Gravity extension, both reversers lost, approach idle only
  4. Normal gear extension, controlled by the BSCU
Show the answer

Answer C: Gravity extension, both reversers lost, approach idle only

With both LGCIUs failed, normal gear control and ECAM position indications are lost, so the gear is extended by gravity. The STATUS lists REVERSER 1+2 inoperative and ENG 1 and ENG 2 APPR IDLE ONLY. GPWS SYS goes OFF, as GPWS gets gear up information. The LDG GEAR panel lights remain if LGCIU 1 is supplied.

FCOM PRO-ABN-LG

Hydraulics

The RAT OUT memo is displayed. When is it amber rather than green?

  1. When the RAT pump is not available
  2. In phases 1 and 2, before takeoff power
  3. Whenever the RAT is out in flight
  4. When stowing pressure is applied to the RAT
Show the answer

Answer B: In phases 1 and 2, before takeoff power

RAT OUT is a green memo when the ram air turbine is not fully stowed, and its colour changes to amber during FWC flight phases 1 and 2, from electrical power on until the first engine is set to takeoff power. A RAT pump not available, or stowing pressure applied, shows as an amber RAT on the HYD SD page.

FCOM DSC-29-20 · ECAM HYD PAGE / FCOM DSC-31-15 · FLIGHT PHASES

Flight Controls

You are flying in Alternate Law after an earlier system failure. As you configure the aircraft for landing and lower the landing gear, what immediate change occurs in the flight control system?

  1. The aircraft degrades from Alternate Law to Direct Law in pitch
  2. The aircraft regains Normal Law protections temporarily for the flare
  3. The aircraft transitions to Mechanical Backup to ensure direct control surface authority
  4. The aircraft remains in Alternate Law, but Flare Mode activates at 50 ft
Show the answer

Answer A: The aircraft degrades from Alternate Law to Direct Law in pitch

In pitch alternate law, selecting the landing gear down changes the flight mode to flare mode, which is a direct stick-to-elevator relationship. So once the gear is down you are in direct law: no protections, no autotrim, and you trim manually.

FCOM DSC-27-20-20 · ALTERNATE LAW / FCOM DSC-27-20-20 · DIRECT LAW

Auto Flight & FMS

During an autoland, below 200 ft RA, which of these makes the AUTOLAND warning light flash?

  1. The A/THR disconnecting
  2. A crosswind above the autoland limit
  3. The FMA landing capability changing from CAT 3 DUAL to CAT 3 SINGLE
  4. The two radio altimeters differing by more than 15 ft
Show the answer

Answer D: The two radio altimeters differing by more than 15 ft

Below 200 ft RA, with at least one AP engaged in LOC and G/S, LAND or FLARE mode, the AUTOLAND light flashes for an excessive localizer (1/4 dot) or glideslope (1 dot) deviation, a loss of LOC or glide signal, the two RA indications differing by more than 15 ft, the last AP disengaging, or a long or untimely flare.

FCOM DSC-22_30-80-30-10 · AUTOLAND WARNING LIGHT / FCOM DSC-31-10 · ECAM Description / FCOM PRO-NOR-SRP-01-70 · LANDING CATEGORIES

Fire Protection

In flight, AGENT 1 has been discharged on a burning engine. When does the ENG FIRE procedure call for AGENT 2?

  1. Straight after AGENT 1, so that both bottles act together
  2. 10 s after AGENT 1, once N1 has decreased
  3. If the fire warning remains 30 s after AGENT 1
  4. Only once the aircraft has landed and stopped
Show the answer

Answer C: If the fire warning remains 30 s after AGENT 1

In flight AGENT 1 is discharged 10 s after the ENG FIRE pb is pushed, so that N1 and nacelle ventilation decrease and the agent works better. If the fire warning remains 30 s after the first agent, the crew discharges AGENT 2.

FCOM PRO-ABN-ENG

Electrical

You land in the emergency electrical configuration, with the RAT still driving the emergency generator and the APU unavailable. As the aircraft decelerates on the runway, what happens to the electrical distribution?

  1. Below 100 kt the DC BAT BUS is connected to the batteries, and below 50 kt the AC ESS BUS is shed, losing all display units
  2. Below 50 kt the DC BAT BUS is connected to the batteries, and below 100 kt the AC ESS BUS is shed, losing all display units
  3. Below 100 kt the emergency generator is shed, and the batteries then supply the DC ESS BUS only
  4. Nothing changes on the ground until maintenance stows the RAT, because the emergency generator remains coupled
Show the answer

Answer A: Below 100 kt the DC BAT BUS is connected to the batteries, and below 50 kt the AC ESS BUS is shed, losing all display units

On the ground below 100 kt the emergency generator has nothing to drive it, so the essential network goes to the batteries and static inverter and the DC BAT BUS is connected to the batteries. Below 50 kt the AC ESS BUS is shed, taking all the display units with it.

FCOM DSC-24-10-30-30 · EMERGENCY GENERATION AFTER LOSS OF ALL MAIN GENERATORS / FCTM PR-AEP-ELEC · TECHNICAL BACKGROUND

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