Пилоты Air Canada оставляют шасси 787 опущенными после взлета, почему?

MONTREAL- Canadian flag carrier, Air Canada (AC), Boeing 787-9 Dreamliner was observed taking off with its landing gear remaining down after liftoff, a deliberate procedural decision by the flight crew.

This unusual configuration was not due to a malfunction but rather a specific compliance with the aircraft’s Minimum Equipment List (MEL 32-12-01) addressing missing door seals in the landing gear bay, reported an aviation enthusiast and aircraft technician, Turbine Traveler, on X.

The intentional non-retraction follows strict safety protocols when operating with certain equipment limitations. Without proper door seals, airflow disruption could potentially compromise fire detection sensors in the wheel wells, requiring pilots to maintain extended gear position for approximately ten minutes after departure to ensure adequate brake cooling and fire safety monitoring.

Photo: wilco737 | Flickr

Air Canada Pilots Leave 787 LG Extended

When operating under specific MEL conditions like missing landing gear door seals, flight crews must follow compensatory procedures to maintain safety margins. In this case, leaving the gear down for ten minutes after takeoff serves multiple critical purposes:

• It allows proper cooling of brake components that may have heated during taxi and takeoff
• It maintains optimal airflow patterns for fire detection systems when door seals are compromised
• It ensures complete wheel spin-down before eventual retraction
• It compensates for limitations in the aircraft’s normal fire detection capability

While this configuration imposes a significant fuel penalty (approximately 1,200kg of additional fuel burn), it represents a carefully calculated safety trade-off that allows continued operations despite minor equipment deficiencies. The extended landing gear creates substantial drag but preserves all safety parameters.

Boeing 787 LG System Specifics

The Boeing 787 Dreamliner features several distinctive characteristics in its landing gear operation that become particularly relevant in these situations:

• Upon liftoff, landing gear doors automatically open in anticipation of gear retraction
• If pilots don’t select gear up within a predetermined timeframe (as in this MEL situation), the doors automatically close again around the extended gear
• During normal operations, gear retraction typically occurs within 10 seconds after takeoff
• The system applies automatic braking to wheels during retraction to prevent gyroscopic forces from spinning wheels from entering the gear bay

For aircraft operating with deactivated brake units (another MEL condition), extended gear position becomes especially important.

The spinning mass of wheels (exceeding 100kg each) creates substantial gyroscopic forces that could stress the landing gear system if retracted while still spinning rapidly. Natural deceleration time prevents potential damage.

By Adam Moreira (AEMoreira042281) – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=80388780

Minimum Equipment List Item

The MEL (Minimum Equipment List) functions as a regulatory-approved document that defines what equipment may be inoperative while still permitting legal flight operations. For Air Canada and other carriers, this critical reference:

• Details specific components that can be temporarily inoperative
• Prescribes compensatory procedures required for continued safe operation
• Establishes time limits for repairs before grounding becomes mandatory
• Ensures safety margins remain adequate despite equipment limitations

In the case of MEL 32-12-01 covering missing gear door seals, the prescribed remedy involves maintaining the extended gear position temporarily after takeoff. This highlights how seemingly unusual flight configurations often represent carefully engineered safety protocols rather than emergencies.

Photo: Anna Zvereva | Flickr

787’s Advanced Braking Technology

The Boeing 787 Dreamliner’s braking system represents cutting-edge aviation technology, manufactured by Safran Landing Systems (formerly Messier-Bugatti-Dowty) in Walton, Kentucky. Unlike conventional hydraulic systems, the 787 employs:

• Fully electric brake actuation
• 32 Electronic Brake Actuators (EBAs) distributed across all wheels
• Carbon brake packs optimized for weight and thermal performance
• Independent electrical control pathways providing redundancy

This electrical architecture offers exceptional reliability, as the system can function even during dual-engine failure scenarios. The braking system can operate from the aircraft’s 28V standby power system, backed by either the APU or Ram Air Turbine (RAT) if necessary.

The 787’s remarkable electrical generation capacity (1.3MW in flight) supports this robust design philosophy.

Thermal Management Considerations

Temperature management represents a critical aspect of landing gear operation. For the 787 and similar modern aircraft:

• Brake temperatures should remain below 200°C before pushback
• Temperatures exceeding 300-400°C during taxi typically trigger a return to stand
• Even after normal landings, brake temperatures typically reach only 300-400°C
• Overheated brakes risk potential fire hazards in gear bays if retracted too quickly

These thermal considerations further explain why extended gear operation becomes necessary under certain MEL conditions. The extended position ensures adequate cooling airflow before eventual retraction, preventing potential heat-related incidents.

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The post Air Canada Pilots Leave 787 Landing Gear Down After Takeoff, Why? appeared first on Aviation A2Z.