Blocked drain put Qantas jet at risk

AN AILING Qantas jumbo jet running on back-up batteries had just minutes of power left after a water leak knocked out electricity to multiple flight systems.

By InvestSMART · 14 Dec 2010

By InvestSMART ·
14 Dec 2010

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AN AILING Qantas jumbo jet running on back-up batteries had just minutes of power left after a water leak knocked out electricity to multiple flight systems.

Overflowing water from two galleys and toilets had seeped through the floor of flight QF2 from London as it was descending on Bangkok airport, short-circuiting three of the four onboard power generators.

The Australian Transport Safety Bureau's final report released yesterday into the January 7, 2008, incident found moisture vulnerabilities to the Boeing 747's electrical power units, as well as information gaps in emergency flight manuals and automatic computer warnings for pilots facing onboard electrical shutdown.

The overflow was traced to an ice "plug" that formed in a drain pipe, due to a broken drainpipe heater.

The flood knocked out radar, cabin pressurisation, auto-pilot, auto-throttle and some fuel pumps.

The pilots decided not to declare an emergency landing, an action investigators think ought to have been taken.

The flight was running on its 30-minute store of battery power for its last 15 minutes, and had been on batteries for 21 minutes by the time the aircraft landed and taxied to the terminal building, investigators found.

If the flooding had occurred more than 30 minutes from landing, it would have placed the plane carrying 346 passengers and 19 crew "at considerable risk" as more flight systems were likely to have failed, investigators said.

Next to fail would have been the plane's communications, air speed, altitude and heading displays, warning systems, navigation and engine instrumentation.

It was difficult for pilots to know how much battery power was left.

The pilots managed to land the ailing craft safely without injuries, but when the engines were shut down, the cabin lighting cut out and the doors could not be opened because the cabin remained pressurised a serious problem in any emergency evacuation.

In response to the investigation, the bureau said "Qantas, Boeing and the US Federal Aviation Administration have implemented a number of safety actions to prevent a recurrence," including reinforcing dripshields above electrical equipment, better maintenance practices and pilot training and installing advanced "standby" 747 flight instruments.

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Frequently Asked Questions about this Article…

What happened on Qantas flight QF2 that put the Boeing 747 at risk?

On January 7, 2008, Qantas flight QF2 from London to Bangkok suffered a major onboard electrical shutdown after overflowing water from two galleys and toilets seeped through the floor and short‑circuited three of the four onboard power generators. The aircraft ran on backup batteries for part of the descent and landed safely, but investigators found the situation had put the plane carrying 346 passengers and 19 crew at considerable risk.

What exactly caused the flooding and electrical failure on the Boeing 747?

Investigators traced the overflow to an ice 'plug' that formed in a drain pipe because a drainpipe heater had broken. The resulting overflow knocked out radar, cabin pressurisation, autopilot, autothrottle and some fuel pumps by short‑circuiting the aircraft's electrical power units.

How long did the 747 run on backup batteries, and why is that important for safety?

The Boeing 747 had a 30‑minute battery backup store. By the time it landed, it had been on battery power for 21 minutes and had only minutes left during the final 15 minutes of flight. Investigators warned that if the flooding had occurred more than 30 minutes from landing, further systems likely would have failed, placing the aircraft at considerable risk.

Which flight systems failed during the incident and which were next at risk?

The flood knocked out radar, cabin pressurisation, the autopilot, the autothrottle and some fuel pumps. Investigators said the next systems likely to fail included communications, airspeed, altitude and heading displays, warning systems, navigation and engine instrumentation.

Did the pilots declare an emergency, and were there problems with emergency procedures?

The pilots decided not to declare an emergency landing, a decision investigators believe should have been taken. The ATSB also identified information gaps in emergency flight manuals and in automatic computer warnings for pilots facing onboard electrical shutdowns.

What vulnerabilities did the Australian Transport Safety Bureau (ATSB) find in the Boeing 747?

The ATSB's final report found moisture vulnerabilities in the Boeing 747's electrical power units and highlighted gaps in emergency flight manuals and automatic warnings, as well as the difficulty pilots had in knowing how much battery power remained during the shutdown.

What safety actions did Qantas, Boeing and the US Federal Aviation Administration implement after the ATSB report?

In response to the investigation, the ATSB said Qantas, Boeing and the US FAA implemented several safety actions including reinforcing dripshields above electrical equipment, improving maintenance practices, enhancing pilot training and installing advanced 'standby' flight instruments for the 747.

What should everyday investors take away from the Qantas Boeing 747 electrical failure?

For everyday investors, the key takeaways are that the incident revealed technical and procedural vulnerabilities which prompted coordinated safety actions by Qantas, Boeing and regulators. Investors monitoring airline or aerospace exposures may want to note how companies address operational safety risks, regulatory responses and ongoing improvements after high‑profile incidents.