Dreamliner back in the news

[Guest]

Pitot tube problems  Also problems with the cockpit seats coming loose.

Concerns raised over incorrect airspeed data readings on Boeing 787 Dreamliners

April 4, 20165:27pm

 

Boeing’s 787 Dreamliners are at the centre of another safety problem. Picture: Kentaro Iemoto

BOEING has run into more problems with its 787 Dreamliners, including fears a problem with airspeed data displays could send aircraft into a mid-flight dive.

The United States Federal Aviation Administration (FAA) has taken the rare step of issuing a safety directive to pilots flying Dreamliners, warning them to avoid abrupt flight-control commands because of unreliable airspeed indicators.

The instruction follows three reported incidents in which the displayed airspeed on Boeing 787s incorrectly dropped significantly below the actual speed of the planes.

The fear is that pilots might respond to the incorrect airspeed data and put the plane into a dive, which would “exceed the structural limits of the 787” and could be a safety hazard, the FAA said.

The FFA’s directive for Boeing 787s was issued without the usual review period, and means the 787 flight manuals will have to be updated with the new instructions for pilots.

 

The cause of the erroneous instrument readings has not been determined but weather was believed to be a factor in the three reported incidents.

According to the FAA, in once incident, the 787 was flying in conditions involving “significant water ingestion and possibly icing” of two of the three devices, called Pitot tubes, that provide speed and altitude information to the air data system.

Heavy rain or ice plugging Pitot tubes emerged as a global aviation safety issue after the fatal crash of an Air France Airbus A330 in the Atlantic in 2009. An investigation found that stressed pilots responded “inappropriately” after airspeed sensors on the A330 malfunctioned.

A Boeing spokeswoman said the company fully supported the FAA’s directive and had worked “closely with the FAA to monitor the fleet and take appropriate actions”, the Wall Street Journal reported.

This is the second safety concern over Boeing’s flagship 787 Dreamliners in the past month.

In March, the FAA ordered that both cockpit seats be replaced on all Boeing 787 aircraft following an incident in which pilot’s seat came loose during an attempted landing.

AN INVESTIGATION by the US Federal Aviation Administration (FAA) is pointing to a serious design flaw in the flight deck seats on Boeing 787 Dreamliners.

Regulators are now proposing a new directive requiring airlines to replace both of the cockpit seats on all 787 aircraft currently in service. The move comes in the wake of an incident in which a pilot’s seat came loose during a landing attempt, Flightglobal reports.

Investigators determined that because of design flaws in the seat, similar incidents in which the “captain’s seat moved during a landing rollout due to a failure in the seat horizontal actuator” might be expected to occur on other Boeing 787 Dreamliners as well.

“Press fit clutch pins in the actuator could migrate loose when subjected to repeated dynamic impact loading,” the FAA warned in the proposed mandate.

“The clutch pins can migrate loose, overturn, and force clutch plate separation, resulting in degraded or failed seat locking.”

Regulators are allowing a three-month comment period before the new requirement is implemented. If the proposal is approved, airlines would be required to replace the malfunctioning seats within a three-year window.

 

Flight deck of the Boeing 787 Dreamliner. Picture: Charles BrewerSource:News Limited

In December 2014, Boeing issued an alert to customers urging operators to replace the cockpit seats.

The proposed FAA rule would make that manufacturer’s recommendation mandatory.

Ipeco, the UK-based supplier of crew seats for the 787, told Flightglobal that “the operator does not have to replace the seat, but rather the actuators on the seat only” and added “the estimated spares replacement costs reported by the FAA are not applicable since the spares are being provided by Ipeco free of charge to all customers”.

It also commented that “it has already supplied replacement actuators for more than 50 per cent of the 787 aircraft affected in advance of this AD and also paid for labour charges to replace the actuators”.

[Guest]

yet another problem:

FAA orders urgent fix to engines that could shut down on Boeing 787s

 

Originally published April 22, 2016 at 12:49 pm Updated April 22, 2016 at 8:43 pm

The FAA ordered airlines to urgently modify engines on Boeing 787 Dreamliners, due to an icing problem that can cause a specific model of GE engine to shut down in flight. The problem affects 176 Dreamliners at 29 airlines, about 44 percent of the worldwide fleet.

 

The Federal Aviation Administration on Friday ordered airlines to urgently modify engines on Boeing 787 Dreamliners, due to an icing problem that can cause a specific model of GE engine to shut down in flight. The problem affects 176 Dreamliners at 29 airlines, about 44 percent of the worldwide fleet, the FAA said.

The FAA’s airworthiness directive follows a Jan. 29 incident in which one of the two engines on a Japan Airlines (JAL) 787 shut down in midair and couldn’t be restarted. The jet, flying from Vancouver, B.C., with 166 people on board, was about 90 miles from Tokyo’s Narita Airport when the right-hand engine failed.

According to data on that flight provided by aircraft-tracking firm Flightradar24, the pilots landed safely on one engine about half an hour later.

On planes with the same engine model on both wings, the problem could cause a potentially catastrophic dual shutdown of both engines.lost  power

The FAA directive says “the potential for common cause failure of both engines in flight is an urgent safety issue.”

The rework ordered by the FAA has already started; GE issued a service bulletin on March 11. GE spokesman Rick Kennedy said rework on about 40 airplanes has been completed.

Airlines have until the first week of October to complete the rework on all their planes. In the meantime, pilots are required to follow a new ice-removal procedure in flight.

The FAA did not issue an emergency directive, its most immediate form of mandatory action. However, because of “the risk to the flying public,” the agency dropped its usual 30-day period for public comment before a directive takes effect.

The agency only regulates U.S. airlines, but government regulators elsewhere typically follow its lead.

The FAA directive, first reported Friday by The Wall Street Journal, states that the problem arises only in the latest upgraded model of the GEnx engine powerng the Dreamliner, the GEnx-1B PIP2.

That upgrade, which was certified by the FAA and entered service in 2013, improved the fuel burn incrementally, in part by reducing the tiny gap between the tips of the engine’s large fan blades and the fan case.

 

In the January incident, ice had built up on the fan blades before the trouble occurred at an altitude of 20,000 feet as the plane descended.

When the ice abruptly shed, it caused the blades to move slightly forward and because of the contour of the fan case, this was enough to make the blade tips rub against the case.

The resultant heavy vibrations did so much damage that the engine shut down and could not be restarted.

 

Luckily, the GEnx engine on the other wing of the JAL Dreamliner was older and not the specific upgraded PIP2 design. The FAA directive says that second engine incurred only “minor damage during the icing event and continued to operate normally.”

However, some aircraft carry two engines of the upgraded PIP2 model type.

The fix GE has devised is to shave “less than 1/10 of an inch of the abradable seal material along the interior of the fan case which makes contact with the tips of the fan blades,” said Kennedy, the GE spokesman.

 

On all new PIP2 engines now being produced, this process is being done during the manufacturing process, increasing the fan-tip clearance to avoid the problem.

Jets already in service will have to be taken into maintenance facilities to have the work done.

“The process takes about 16 hours using a ‘fan grinding machine.’ All of the work is done on-wing with no engine removals,” Kennedy said.

He added that “because the shaving occurs in front of the fan blades, we expect almost immeasurable (fuel efficiency) performance impact” on the reworked engines.

This fix is being initially performed on all 176 airplanes in service that have two engines of this type. However, the FAA said it later may issue further directives to require rework of other affected engines.

 

Until airlines worldwide complete that work, the airworthiness directive mandates that 787 pilots be briefed on the problem and use a revised fan-ice removal procedure in flight.

When the system indicator in the cockpit lights up to indicate an ice buildup, or when ice buildup is suspected due to high engine vibration, the pilots are instructed to momentarily rev both engines close to full throttle every five minutes.

Kennedy said this latest icing problem is not related to an earlier engine issue that affected a series of GEnx-powered 787s in 2013, in which ice crystals built up inside the core of the engine at very high altitudes under certain unusual weather conditions. That issue was fixed by modifying the engine-control software.

[Canoehead]

24 minutes ago, Malcolm said:

The resultant heavy vibrations did so much damage that the engine shut down and could not be restarted.

I'm not a "Jet Driver", but is it standard practice to attempt to restart an engine that shut down (failed?) due to excessive vibration- enough to cause "much damage"?

Also, interesting that the second "unaffected" engine on the JAL flight only sustained "minor damage" during the icing event...

 

[conehead]

You'd think that the very last logic gate in the software to command auto-engine-shutdown would be "is the other engine operating?"...  If "no", then it shouldn't shut down.  Too much automation?

[DEFCON]

Now there's a 'logical' question!