Educational familiarization only. This original TechOpsBase resource explains system purpose, architecture and maintenance reasoning. It does not reproduce Airbus pages, diagrams, task instructions or controlled maintenance data. Actual aircraft work requires current approved data, correct effectivity, operator procedures, authorization and supervision.
Resource profile
- Aircraft: Airbus A350 family
- ATA chapter: 27 - Flight Controls
- Audience: Students, junior technicians and working professionals
- Level: Intermediate familiarization
- Source basis: Privately supplied 2013-2014 manufacturer training and MSG-3 material
- Technical status: Draft pending technical review
Learning objectives
- Explain speed-brake and ground-spoiler objectives.
- Identify deployment prerequisites and inhibition logic.
- Describe MLA and GLA functions.
- Relate spoiler faults to operational effects.
1. Symmetric spoiler use
Symmetric spoiler deployment reduces lift and increases drag. In flight, the speed-brake function helps manage energy and descent. After touchdown, ground spoilers dump lift so aircraft weight transfers rapidly to the landing gear and braking becomes more effective.
Maintenance questions to ask
- What is the commanded condition and what independent evidence confirms it?
- Which computer, sensor, hydraulic and electrical channels are required in this configuration?
- Is the failure crew-evident, maintenance-evident or hidden until a dedicated test?
- Which current approved document and effectivity control the next action?
2. Command logic
The speed-brake lever provides the primary pilot command, but PFCS limits deployment according to configuration, angle of attack, thrust and other conditions. Ground-spoiler deployment uses several independent landing-state inputs to prevent inadvertent extension in flight.
Maintenance questions to ask
- What is the commanded condition and what independent evidence confirms it?
- Which computer, sensor, hydraulic and electrical channels are required in this configuration?
- Is the failure crew-evident, maintenance-evident or hidden until a dedicated test?
- Which current approved document and effectivity control the next action?
3. Automatic functions
Spoilers can support manoeuvre load alleviation and gust load alleviation. These functions reduce structural load by distributing aerodynamic response across the wing. They are computed in the PRIMs and depend on valid aircraft-motion and air-data inputs.
Maintenance questions to ask
- What is the commanded condition and what independent evidence confirms it?
- Which computer, sensor, hydraulic and electrical channels are required in this configuration?
- Is the failure crew-evident, maintenance-evident or hidden until a dedicated test?
- Which current approved document and effectivity control the next action?
4. Failure effects
One failed spoiler may reduce roll, speed-brake or ground-spoiler capability without removing the entire function. A failed actuator can be held in anti-extension to prevent aerodynamic lift-up. Performance calculations and dispatch status depend on the number and location of unavailable panels.
Maintenance questions to ask
- What is the commanded condition and what independent evidence confirms it?
- Which computer, sensor, hydraulic and electrical channels are required in this configuration?
- Is the failure crew-evident, maintenance-evident or hidden until a dedicated test?
- Which current approved document and effectivity control the next action?
5. Indications
The F/CTL system page shows surface position. Warnings identify failed or unavailable functions. A commanded surface that does not move must be distinguished from a display or feedback error. Cross-check actual position, actuator status and maintenance messages.
Maintenance questions to ask
- What is the commanded condition and what independent evidence confirms it?
- Which computer, sensor, hydraulic and electrical channels are required in this configuration?
- Is the failure crew-evident, maintenance-evident or hidden until a dedicated test?
- Which current approved document and effectivity control the next action?
6. Maintenance safety
Spoilers can move rapidly and create crush hazards. Use surface locks or approved safety devices where required. Confirm hydraulic and electrical isolation before access, and treat stored or backup actuation capability as live until the approved procedure establishes a safe state.
Maintenance questions to ask
- What is the commanded condition and what independent evidence confirms it?
- Which computer, sensor, hydraulic and electrical channels are required in this configuration?
- Is the failure crew-evident, maintenance-evident or hidden until a dedicated test?
- Which current approved document and effectivity control the next action?
Integrated review
Use the input ? computation ? power ? actuation ? feedback ? indication model. A correct diagnosis must explain both the physical symptom and every associated message. Avoid replacing a computer merely because it generated the warning; it may be reporting loss of an external input, power source or actuator response.
Key takeaways
- Explain speed-brake and ground-spoiler objectives.
- Identify deployment prerequisites and inhibition logic.
- Describe MLA and GLA functions.
- Relate spoiler faults to operational effects.
Current approved maintenance data always controls aircraft work.
