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Ground Spoilers and Function Allocation

A 200-plus-tonne aircraft arrives on the runway at well over 130 kt, and the next thirty seconds must wash that speed down to taxi speed. Three systems do it — ground spoilers, thrust reversers, and wheel brakes — and the FCTM lists the ground spoilers first. Not because they brake hardest (the wheel brakes do that), but because they have to act first for the other two to work: the moment the panels stand up, the wing's lift is destroyed, the aircraft's weight transfers from wing to wheels, and only then can the brakes bite and the reversers earn their keep.

This is the third job of the same six panels article 22 introduced as roll-assist and speedbrake surfaces. The motion is identical — the panel rises to spoil lift — but the logic is a system in its own right, and its most striking feature is that the pilot never "deploys" the ground spoilers by pressing anything. The crew's only action is to arm the function during the approach; from then on the computers decide when the panels open, how far, and when they retract, by reading wheel speed, thrust-lever position, main-gear compression, and reverser selection. This article resolves two things together: the automatic extension gate (which signals trigger deployment, in which flight phase, armed or not), and the full function-allocation matrix — which panel belongs to which computer, draws which hydraulic system, and performs which of the four jobs.

Two warnings up front, because both run hard against instinct and reshape everything that follows:

[!warning]- Arming is not the prerequisite for deployment — reverse is the back-up trigger.

The reflex is "if I don't arm the ground spoilers, they won't deploy." Wrong. Arming only changes which signal triggers extension, not whether the panels come out. If you forget to arm (GND SPLR NOT ARMED), the panels still deploy fully on touchdown the instant reverse is selected on at least one engine. Arming is the preferred path (extension on thrust-levers-idle); reverse is the safety net for the un-armed case. Carry the wrong model into the flare and you will misjudge what happens when an item is missed.

[!warning]- The 72 kt threshold is wheel speed, not airspeed, and it gates only the rejected-take-off phase.

The "72 kt" in the ground-spoiler logic is read off the wheels, not the air data, and it appears only in the rejected-take-off gates. The landing phase does not use it at all — it uses the harder physical fact of both main gears touching down. Read 72 kt as an airspeed, or apply it to landing, and you have the logic wrong in both axes.

1. The six panels in their third role — the function-allocation matrix

The maintenance source states the whole division of labour in one paragraph — this is the backbone of the chapter. Per AMM 27-00-00:

Six spoilers are installed on each wing; they are used in the functions below: - spoilers 2 thru 6: Roll control, in manual control mode, mainly from the side sticks, or in autopilot control mode, from the FMGECs. - spoilers 1 thru 6: Speedbrake function, from the speedbrake control lever, and ground spoiler function. - spoilers 4 thru 6: Maneuver Load Alleviation (MLA). Each spoiler is actuated by an electrohydraulic servo control [...] driven by one FCPC or one FCSC.

Three panel ranges, and they do not coincide. Lay them over the per-panel hydraulic and computer assignment (article 22, per AMM 27-64-00 and ASM 27-98-31 thru 35) and the single most useful picture of the whole system falls out:

        FUSELAGE ◄──────────────── panels 1..6 ────────────────► WINGTIP
        ┌───────┬───────┬───────┬───────┬───────┬───────┐
 HYD    │   G   │   B   │   B   │   Y   │   G   │   Y   │   Green  = 1 & 5
 panel  │   1   │   2   │   3   │   4   │   5   │   6   │   Blue   = 2 & 3
        ├───────┼───────┼───────┼───────┼───────┼───────┤   Yellow = 4 & 6
 CPU    │ PRIM3 │ PRIM3 │ SEC 2 │ PRIM2 │ PRIM1 │ SEC 1 │
        └───────┴───────┴───────┴───────┴───────┴───────┘
 roll       —       o       o       o       o       o       roll       : 2-6
 speedbrk    o       o       o       o       o       o       speedbrake : 1-6
 ground      o       o       o       o       o       o       ground     : 1-6
 MLA         —       —       —       o       o       o       MLA        : 4-6
 jobs        2       3       3       4       4       4

Four things to read off it, each developed below or in the linked articles:

  1. One bank of panels, up to four jobs — but not every panel does all four. Spoiler 1 does only two jobs (speedbrake + ground spoiler): it never assists roll and never serves MLA. Spoilers 2 and 3 add roll, for three jobs. Spoilers 4, 5 and 6 do all four (they are also the MLA panels — see Load Alleviation). This is exactly why an ECAM panel-fault message, and any MEL performance penalty, depend on which panel is lost: drop spoiler 1 and you lose only deceleration and lift-dump; drop spoiler 5 and you lose a piece of all four capabilities at once.
  2. Hydraulics are cross-allocated against a single-system loss. Green feeds 1 & 5, Blue feeds 2 & 3, Yellow feeds 4 & 6 — two panels per system per wing. Lose any one hydraulic system and four of the six panels per wing still work (lose Green and you lose only 1 & 5; 2, 3, 4, 6 remain). This is the root of the ground spoiler keeping most of its lift-dump effectiveness even on a single hydraulic failure.
  3. More PRIM than SEC. Four panels run on PRIM (1 & 2 on PRIM 3, 4 on PRIM 2, 5 on PRIM 1) and two on SEC (3 on SEC 2, 6 on SEC 1). Note that panel 1 sits on PRIM 3 yet does no roll — which is why FCOM's roll sentence, the SECs control the N° 3 and 6 spoilers ; the PRIMs control the N° 2, 4 and 5 spoilers, deliberately omits panel 1. That sentence is about the roll function only; do not read it as "panel 1 has no computer."
  4. The ground-spoiler command is a PRIM-computes / SEC-executes relay — §2.

[!warning]- For the ground spoiler (and speedbrake) function, a failed panel disables its symmetric partner with no exception — unlike the roll function, which exempts panels 4 and 6.

Per FCOM, when a ground spoiler surface on one wing fails, the symmetric one on the other wing is inhibited. That is all six panels, no exception — because lift must be dumped symmetrically or the asymmetric loss of lift produces an unwanted rolling moment at the worst possible moment. The roll function, by contrast, inhibits the symmetric partner except for spoilers 4 and 6 (they are the MLA panels, and pairing them off would weaken load-alleviation symmetry — see article 22). So "symmetric inhibition" is not one rule you can memorise across all jobs: speedbrake and ground spoiler are all-six-no-exception; roll excepts 4 and 6.

2. Signal flow — PRIM computes, SEC executes

The ground-spoiler command does not run straight from a sensor to a panel. The maintenance source traces the exact relay. Per AMM 27-60-00:

For the ground spoiler function the FCPCs send a signal to the FCSCs. The FCSCs send the signal to the spoiler servocontrols. The servocontrols extend the spoilers automatically. One FCPC or one FCSC controls each servocontrol. The position of each servocontrol is shown on the lower ECAM display screen in the aircraft cockpit via the Flight Control Data Concentrators (FCDC).

Read four facts out of that one passage:

Because the PRIM is the brain, the dedicated ground-spoiler ECAM caution (F/CTL GND SPLR FAULT) is a loss of the PRIM-computed function, handled in the failure articles (EFCS Computer Failures and Degradation, Control Surface Fault Spectrum).

3. Arming — the pilot's only action

What the crew actually does, FCOM states in one line. Per FCOM DSC-27-10-20:

The pilot arms the ground spoiler function by pulling the speedbrake control lever up into the armed position.

The elegance is that the ground spoiler and the speedbrake share one lever. Pushing it fore-and-aft in flight works the speedbrake; pulling it up into the armed detent on approach tells the computers "you are authorised to deploy the ground spoilers automatically at landing." On the ECAM a green memo confirms it. Per FCOM DSC-27-20-30:

GND SPLRS ARMED : This memo appears in green, when the ground spoilers are armed.

Arming is read aloud as part of the approach flow on the standard operating procedure, and the green memo is the crew's confirmation that the armed path is set. But — the first warning callout — arming is the preferred trigger, not the only one. The next section shows that the un-armed case is fully covered by reverse selection.

4. Full extension — the four-quadrant gate

This is the heart of the system. FCOM splits "when do the panels open fully" by flight phase — rejected take-off, and landing/bounce — and within each phase by armed / not armed. Per FCOM DSC-27-10-20:

FULL EXTENSION - REJECTED TAKEOFF PHASE ‐ If the ground spoilers are armed and the wheel speed exceeds 72 kt, the ground spoilers will automatically extend as soon as all thrust levers are set to idle. ‐ If the ground spoilers are not armed and the wheel speed exceeds 72 kt, the ground spoilers will automatically extend as soon as reverse is selected on at least one engine (remaining engine at idle).

and:

FULL EXTENSION - LANDING PHASE / BOUNCE ‐ If the ground spoilers are armed and all thrust levers are at idle, the ground spoilers will automatically extend as soon as both main landing gears have touched down. ‐ If the ground spoilers are not armed and both main landing gears have touched down, the ground spoilers will automatically extend as soon as reverse is selected on at least one engine (remaining engine at idle).

Compress those four bullets into one gate (logical structure synthesised from the two FCOM passages; the cell contents are FCOM verbatim):

                  GROUND-SPOILER FULL EXTENSION — the four gates
  ┌─────────────────┬──────────────────────────────┬──────────────────────────────┐
  │                 │  ARMED  (preferred path)      │  NOT ARMED  (reverse net)     │
  ├─────────────────┼──────────────────────────────┼──────────────────────────────┤
  │ Rejected        │  wheel speed > 72 kt          │  wheel speed > 72 kt          │
  │ take-off (RTO)  │  AND all thrust levers idle   │  AND reverse on ≥ 1 engine    │
  │                 │  ─────────► full extension    │  ─────────► full extension    │
  ├─────────────────┼──────────────────────────────┼──────────────────────────────┤
  │ Landing /       │  all thrust levers at idle    │  both main gears touched down │
  │ bounce          │  AND both main gears down     │  AND reverse on ≥ 1 engine    │
  │                 │  ─────────► full extension    │  ─────────► full extension    │
  └─────────────────┴──────────────────────────────┴──────────────────────────────┘
   ARMED  fires on "thrust levers idle + ground evidence (72 kt wheel speed / both gears)".
   NOT ARMED  always needs reverse — reverse is the safety net when arming was missed.

Now the mechanism, condition by condition:

the pilot must ensure that all thrust levers are at IDLE detent at the latest at touchdown, to ensure ground spoilers extension at touchdown.

If a thrust lever is still above idle at touchdown (a missed retard), the armed gate's condition is not met and the panels do not open at the moment of contact — costing you the most valuable second or two of lift dumping. This is a real, occurring human error, which is why the automatic "RETARD" callout exists late in the flare.

So the pilot's mental self-check on every landing is four questions: Did I arm? Are the thrust levers at idle? Are both main gears down? And if any of those is missing, did I select reverse? Any qualifying combination opens the panels; only the fully-empty case (un-armed and no reverse) leaves them stowed, with the deceleration reduced to wheel brakes alone and the stopping distance noticeably longer.

5. Partial extension — the bootstrap that seats the aircraft

FCOM describes a transitional state before full extension that many pilots overlook but which is quietly ingenious. Per FCOM DSC-27-10-20:

PARTIAL EXTENSION The ground spoilers partially extend when reverse is selected on at least one engine (other engine at idle) and one main landing gear is compressed. This partial extension, by decreasing the lift, will ease the compression of the second main landing gear, and consequently will lead to the normal ground spoiler extension.

It solves a real physical problem: at touchdown the two main gears often do not compress simultaneously — in a crosswind landing one wheel touches first, or the aircraft is still partly "floating" on residual lift. While that lasts, the "both main gears down" condition for full extension is not met, the panels stay stowed, and the wheels cannot be pressed firmly enough to brake.

The A330 answer is a bootstrap: with one main gear compressed and reverse selected, the panels open partially → that partial deflection spoils a little lift → more of the aircraft's weight settles onto the wheels → the second main gear compresses → the full-extension condition is now satisfied → the panels go fully up. A small action triggers a larger one — a positive-feedback chain that actively pushes the half-seated aircraft past the tipping point. The FCTM names it the partial lift dumping function. Per FCTM PR-NP-SOP-250:

When the aircraft touches down with at least one main landing gear and when at least one thrust lever is in the reverse sector, the ground spoilers partially automatically deploy to ensure that the aircraft is properly sit down on ground. This is the partial lift dumping function. Then, the ground spoilers automatically fully deploy.

For the pilot this means: in the second or two when one wheel is down and the aircraft is still floating, there is no need to worry that the panels have not yet fully opened — provided you have selected reverse, the partial function is already seating the aircraft, and full extension follows immediately. It is also why the FCTM technique is to select reverse promptly after main-gear touchdown: reverse is not only a decelerator, it is the trigger for partial extension.

6. What the ground spoilers actually do — three physical paths

The FCTM separates the ground spoilers' contribution to stopping into distinct physical mechanisms the pilot should keep apart. Per FCTM PR-NP-SOP-250:

The ground spoilers contribute to aircraft deceleration by increasing aerodynamic drag at high speed. Wheel braking efficiency is improved due to the increased load on the wheels. Additionally, the ground spoiler extension signal is used for autobrake activation.

Three paths, three different mechanisms:

  1. Direct drag (high-speed segment). A raised panel is itself a large drag surface and, at high speed, supplies a direct aerodynamic deceleration force. But this is effective only while fast; as speed falls, drag decays with the square of speed.
  2. Lift dump → wheel load → braking efficiency (the main contribution throughout). This is the most important effect. With wing lift destroyed, the force that was "carrying" the aircraft disappears and full weight presses onto the wheels. Wheel-brake stopping force is proportional to wheel load (friction = μ × load), so the heavier the load, the harder the brakes can bite. Without the ground spoilers the wheels can stay half-floating and skid, and braking is wasted — which is why the wheel brakes contribute most, but only once the ground spoilers have put the load on.
  3. Autobrake trigger. The ground-spoiler extension signal is one of the conditions that activate autobrake, binding the two systems together logically. Per FCOM DSC-32-30-10:

Automatic braking is activated: ‐ At the command for ground spoilers extension (Refer to DSC-27-10-20 Speedbrake and Ground Spoiler Control - Speedbrake Control), for LO and MED modes, or ‐ At the command for ground spoilers extension, when the wheel speed is above 40 kt and when the nose landing gear is compressed, for MAX mode.

The dependency runs the wrong way for the pilot to ignore: if the ground spoilers do not extend, the autobrake trigger never fires. FCOM spells out the consequence for a low-speed reject. Per FCOM DSC-32-30-10:

Consequently in the event of an acceleration stop, if the deceleration is initiated with the wheel speed below 72 kt, the automatic braking will not activate because the ground spoilers will not be extended.

So a ground spoiler that fails to deploy is far more than "a little less aerodynamic drag" — it cascades into skidding wheel brakes and an inactive autobrake. One panel's logic pulls the whole ground-deceleration chain with it; the detailed fault handling and landing-distance impact belong to the failure and landing-gear chapters.

7. Retraction — and the rejected-landing interlock

Once the panels are up, when do they come down? FCOM gives two retraction paths. Per FCOM DSC-27-10-20:

RETRACTION The ground spoilers retract when: ‐ One thrust lever is above idle, or ‐ All thrust levers are at forward idle, and the speedbrake control lever is pushed down.

The two paths cover two situations:

For the pilot the message is that retraction is automation protecting you first: the moment you advance thrust to go around, the panels clear themselves out of the way. But on a normal landing you must still actively disarm / push the lever down before the next phase — leaving them armed and standing into a touch-and-go would be a problem.

8. Operational view — flying the logic

Six scenes turn the static gate into a moving picture:

  1. Approach, arming. Configuration set, gear down; the speedbrake lever is pulled up to the armed detent, the call is made, and the green GND SPLRS ARMED memo appears. The armed path is now set.
  2. Normal landing, full extension at touchdown. Flare at about 40 ft, RETARD callout, all thrust levers to the IDLE detent. Both main gears touch → armed path fires: thrust levers idle + both main gears down → full extension → lift destroyed, aircraft seated → select reverse → autobrake activates (triggered by the ground-spoiler extension signal).
  3. Crosswind, one wheel first. The right main gear compresses while the left still floats; "both main gears down" is not yet satisfied — but reverse is selected → partial extension fires: one gear compressed + reverse → partial deflection → a little lift dumped → the left gear settles → full extension. You feel a "partial-then-full" two-stage motion; it is by design, not a fault.
  4. Arming missed (GND SPLR NOT ARMED). The arm step was skipped on approach. After landing, select reverse → un-armed path fires: both main gears down + reverse → full extension regardless. Reverse saved it. Had you neither armed nor selected reverse, the panels stay stowed, deceleration falls to wheel brakes alone, and the stopping distance grows.
  5. Rejected take-off. High-speed reject; armed before take-off per procedure, wheel speed long past 72 kt. Bring all thrust levers to idle → RTO armed path: wheel speed >72 kt + all thrust levers idle → immediate full extension → working with autobrake and reverse for maximum stopping. (Un-armed at take-off, reverse selection triggers it instead.)
  6. Rejected landing. Panels are fully up; you decide to go around and advance the thrust levers → "one thrust lever above idle" → panels retract automatically → lift returns and the aircraft can climb away. No manual stowing required — the automation clears the path for you.

Self-test

[!note]- Q1. Which panels act as ground spoilers, is arming the pilot's only action, and does an un-armed system fail to deploy?

All six panels (1–6) act as ground spoilers (per FCOM), the same bank and the same lever as the speedbrake. The pilot's only action is to pull the speedbrake lever up into the armed detent on approach — after that the computers decide when, how far, and when to retract. But arming is not a prerequisite for deployment: even un-armed (GND SPLR NOT ARMED), the panels deploy fully after touchdown the moment reverse is selected on at least one engine (both main gears down). Arming is the preferred trigger; reverse is the safety net. "No arming means no spoilers" is simply false — only the trigger signal changes from "thrust levers idle" to "reverse selected."

[!note]- Q2. Is 72 kt airspeed or wheel speed, why that quantity, and which phase uses it?

72 kt is wheel speed, and it gates only the rejected-take-off phase. Wheel rotation, not airspeed, is used because a reject needs unambiguous proof the aircraft is rolling fast on the ground — airspeed is disturbed by wind and instrument error, and main-gear compression can momentarily release over a bump, but the spinning wheels cannot lie. 72 kt sits in the "clearly accelerating but not yet at V1" band so a reject deploys the panels in time. The landing phase does not use 72 kt — it uses the firmer fact of both main gears touched down.

[!note]- Q3. What is partial extension, what physical problem does it solve, and what triggers it?

Partial extension is a transitional state before full extension: with one main gear compressed and reverse selected on at least one engine, the panels open partially (per FCOM). It solves the problem that the two main gears often do not compress together — a crosswind landing on one wheel, or an aircraft still floating on residual lift — which would otherwise leave the "both gears down" full-extension condition unmet. The solution is a bootstrap: partial deflection spoils a little lift → more weight settles on the wheels → the second gear compresses → full extension follows. The FCTM calls it the partial lift dumping function. It is also why reverse should be selected promptly after touchdown: reverse is the trigger for partial extension, not just a decelerator.

[!note]- Q4. By what physical paths do the ground spoilers help stop the aircraft, and why does a ground-spoiler failure ripple into the autobrake?

Three paths (per FCTM): (1) direct aerodynamic drag at high speed; (2) lift dump → increased wheel load → improved wheel-braking efficiency — the main contribution, because brake friction is proportional to wheel load; and (3) the ground-spoiler extension signal triggers autobrake activation (per FCOM DSC-32-30-10, for LO/MED modes; MAX additionally needs wheel speed >40 kt and nose gear compressed). Because autobrake activation depends on the ground-spoiler extension command, if the panels do not extend the autobrake trigger never fires — FCOM notes that a low-speed reject below 72 kt will not activate autobrake for exactly this reason. So a panel that fails to deploy cascades into skidding brakes and an inactive autobrake, not merely "less drag."

[!note]- Q5. In the function matrix, what fundamentally distinguishes spoiler 1 from spoilers 4/5/6, and why does spoiler 1 not assist roll?

Per AMM, spoiler 1 does only two jobs (speedbrake + ground spoiler) — no roll (roll uses 2–6), no MLA (MLA uses 4–6) — while spoilers 4, 5 and 6 do all four (roll + speedbrake + ground + MLA). Spoiler 1 is excluded from roll because it sits at the most inboard station with the shortest moment arm, contributing little rolling moment and limited in travel (the dedicated deceleration panel with the shortest stroke and smallest speedbrake limit — see article 22). So losing spoiler 1 affects only deceleration and lift-dump, whereas losing spoiler 5 chips a piece off all four capabilities.

[!note]- Q6. How do the ground spoilers retract, and what protects a go-around after touchdown?

Two paths (per FCOM): any one thrust lever advanced above idle retracts them automatically, or all thrust levers at forward idle with the speedbrake lever pushed down retracts them manually. The first is the rejected-landing interlock: advancing thrust for a go-around after touchdown automatically retracts the panels so they no longer spoil lift, making a safe climb-away possible without the crew first stowing them by hand. The manual path is the normal-landing case — disarm / push the lever down after vacating the runway (and before a touch-and-go).

Key takeaways

# Point
1 Same six panels (1–6), third job. Function matrix: roll 2–6, speedbrake 1–6, ground spoiler 1–6, MLA 4–6. Spoiler 1 = two jobs only; panels 4–6 = all four. A panel fault's consequences depend on which panel.
2 The pilot's only action is to ARM (pull the speedbrake lever up; green GND SPLRS ARMED memo). Everything after — when, how far, when to retract — is automatic. Arming is the preferred trigger, not a prerequisite.
3 Four-quadrant full-extension gate: armed fires on thrust-levers-idle + ground evidence (72 kt wheel speed for RTO / both main gears for landing); not armed always needs reverse. 72 kt is wheel speed, RTO-phase only.
4 Partial extension (partial lift dumping) = bootstrap: one gear compressed + reverse → partial deflection → seats the second gear → full extension. Solves the non-simultaneous-touchdown / crosswind float case.
5 Three deceleration paths: high-speed drag; lift dump → wheel load → braking efficiency (the main one); and the extension signal triggers autobrake (DSC-32-30-10). A panel that fails to deploy cascades into skidding brakes + no autobrake.
6 Retraction: any thrust lever above idle retracts automatically (the rejected-landing interlock); all-idle + lever pushed down retracts manually. Symmetric inhibition is all-six, no exception for ground spoiler / speedbrake (roll excepts 4 & 6). PRIM computes, SEC executes, one computer per panel — spoiler control is not taken over.

References

Per FCOM DSC-27-10-20 (Ground Spoiler Control — spoilers 1 to 6 act as ground spoilers; symmetric-failure inhibition with no exception; arming by the speedbrake lever; full-extension gates for rejected-take-off and landing/bounce phases, armed and not-armed; 72 kt wheel-speed threshold; partial extension; retraction logic; and the roll allocation SEC 3 & 6 / PRIM 2, 4 & 5 and roll symmetric-failure exception for spoilers 4 and 6; speedbrake deflection 25°/30° reduced in CONF 2/3/FULL). Per FCOM DSC-27-20-30 (green GND SPLRS ARMED ECAM memo). Per FCOM DSC-32-30-10 (autobrake activation at the ground-spoiler extension command for LO/MED, and wheel speed >40 kt + nose-gear compressed for MAX; no autobrake on a reject below 72 kt because the ground spoilers are not extended). Per AMM 27-00-00 (six spoilers per wing and the function ranges — roll 2–6, speedbrake/ground 1–6, MLA 4–6; each driven by one FCPC or one FCSC). Per AMM 27-60-00 (ground-spoiler signal chain FCPC → FCSC → servocontrol, automatic extension, one computer per panel, position shown on ECAM via the FCDC; speedbrake lever signal chain). Per AMM 27-64-00 (hydraulic allocation Green 1 & 5 / Blue 2 & 3 / Yellow 4 & 6; per-panel controlled travel — detail in article 22). Per ASM 27-98-31 thru 35 (per-panel control-computer assignment). Per FCTM PR-NP-SOP-250 (the three ground deceleration systems with ground spoilers first; partial lift dumping function; lift dump improving wheel-braking efficiency; ground-spoiler extension signal used for autobrake; thrust levers at IDLE detent by touchdown to ensure extension). Per FCTM PR-NP-SP-40 (disarm the ground spoilers during touch-and-go). Hydraulic-system dependency per ATA-29; landing-gear compression signals, wheel speed, autobrake rates and landing-distance computation belong to the Landing Gear chapter (ATA-32). The full ground-spoiler deflection angle is not separately stated in FCOM (the 35° figure is the maximum spoiler deflection given for the roll function); the cause-and-effect rationale for the 72 kt wheel-speed choice, for spoiler 1's exclusion from roll, and the cascade from a failed panel to skidding brakes and inactive autobrake are integrative synthesis consistent with the cited sources, not single verbatim manual statements.

Independent study material, not an Airbus publication and not endorsed by the manufacturer. Always defer to the current operator FCOM, FCTM, and QRH for operational use.

ESC