Fuel Leak Management: One decision. 5.7 tons of fuel. Here's what happened.
After training thousands of pilots through their type ratings and emergency procedures, I've seen one pattern emerge consistently: the difference between a successful career and a terminated one often comes down to a single moment of decision-making under pressure. Few scenarios test this more than fuel leak management.
A recent A330 incident perfectly illustrates how even experienced crews can make critical errors when they second-guess their training. This case study should be required reading for every pilot pursuing their type rating or preparing for recurrent training.
The Incident: When Experience Overrides Procedure
During a routine night flight, an A330 crew discovered a fuel discrepancy during their first cruise fuel check. What started as a 1.4-ton difference escalated into a 5.7-ton fuel loss with a dangerous 3.5-ton imbalance by landing.
Here's where it gets critical: despite clear QRH procedures requiring engine shutdown, the crew kept the affected engine running throughout the emergency. This decision created multiple cascading risks that nearly turned a manageable situation into a catastrophe.
The Root Cause: A Maintenance Error with Deadly Potential
Investigation revealed incorrect assembly of the primary fuel hose at the pylon-engine interface.
The mounting flange wasn't properly aligned, allowing vibrations to create a constant leak of 45 liters per minute - equivalent to 2 tons per hour.
This highlights a crucial point I always emphasize in training: mechanical failures happen. Your job as pilot-in-command is to manage them according to established procedures, not to troubleshoot or minimize them.
Critical Decision Point: When the QRH Says "Shutdown"
The crew's fatal flaw was stopping their QRH procedure when it required engine shutdown. After isolating fuel tanks and confirming a 990kg increase in imbalance over 26 minutes, the procedure clearly directed: shut down the affected engine.
Why did they hesitate?
Likely the same reason many pilots do:
- Fear of single-engine approach complexity
- Concern about passenger anxiety
- Overconfidence in their ability to manage the situation
- Misunderstanding of the true fire risk
The Cascading Consequences of Non-Compliance
By keeping the engine running, this crew created multiple additional hazards:
- Fire Risk: Fuel continued spraying onto hot engine components throughout the flight. This wasn't just a leak - it was a potential inferno waiting for an ignition source.
- Environmental Contamination: Fuel dispersed into the atmosphere and contaminated the runway, creating hazards for subsequent operations.
- CG Management: With fuel transfers interrupted, the aircraft's center of gravity moved dangerously aft, reaching 39.8% - just 0.7% below the red alert threshold.
- Extended Exposure: What could have been contained early continued for hours, multiplying every risk factor.
Early Detection: Your First Line of Defense
The silver lining in this case was proper fuel monitoring. The crew detected the leak through systematic fuel checks - exactly as SOPs require. This is why I constantly emphasize to my trainees:
Check 1: Compare (FOB + Fuel Used) against Block Fuel every 30 minutes
Check 2: Verify FOB against FMS predictions and flight plan estimates
Modern ECAM Alerts: Safety Nets, Not Primary Detection
Today's aircraft include automatic fuel leak detection:
- FUEL F.USED/FOB DISAGREE (A320 family, A330, A340)
- FUEL LEAK SUSPECTED (A350)
- FUEL LEAK DETECTED (A380)
- ENG FUEL LEAK alerts for engine-specific leaks
However, these are backup systems. Manual monitoring remains your primary defense because:
- ECAM alerts have threshold delays
- Leak location affects which alerts trigger
- Early detection always provides more options
The Three-Step Fuel Leak Philosophy
Every fuel leak procedure follows the same logical progression:
Step 1: Engine Leak Assessment Engine/Pylon leaks are most common and most dangerous. Look for:
- Visible fuel spray from engine/pylon
- Significant N1 decrease on one side
- Excessive fuel flow on one side If confirmed: Shut down immediately. No exceptions, no delays.
Step 2: Tank Isolation and Monitoring If engine leak isn't obvious:
- Close crossfeed valve
- Switch center tanks OFF - Isolate trim tank feed
- Monitor fuel depletion rates
Step 3: Confirmation Testing
- Asymmetric depletion: Shut down affected engine to confirm location
- Symmetric depletion: Suspect center tank, trim tank, or APU feed issues
Training Captain Insights: What I've Learned
After seeing countless simulator sessions and real-world incidents, here's what separates successful pilots:
Trust Your Procedures: The QRH wasn't written by committees - it was developed through analysis of real incidents and extensive testing. When it says "shutdown," that's not a suggestion.
Understand the "Why": Engine shutdown during fuel leaks isn't just about stopping the leak. It's about preventing the catastrophic fire that could consume your aircraft.
Practice Fuel Monitoring: Make those 30-minute fuel checks as automatic as your instrument scans. The crews who catch problems early have the most options.
Complete the Procedure: Stopping halfway through a QRH procedure because you're uncomfortable with the next step is how incidents become accidents.
Key Takeaways for Your Next Simulator Session
- Fuel leak = immediate consideration for nearest suitable airport
- Engine shutdown is fire prevention, not just leak containment
- Complete QRH procedures don't have optional steps
- Regular fuel monitoring beats ECAM alerts for early detection
- Never use thrust reversers with confirmed fuel leaks
When you're sitting in that simulator facing a fuel leak scenario, remember this A330 crew. Don't let experience override training, and don't let comfort zones compromise safety.
Your preparation today determines your performance when it matters most. Master these procedures now, because when fuel is spraying onto hot engines at 37,000 feet, hesitation isn't an option.