EASA Issues De-Pairing Order For Boeing 787 Trent 1000 Engines

EASA, The European Union Aviation Safety Agency, has issued an airworthiness directive regarding Rolls Royce Trent 1000 engines. The airworthiness directive instructs operators to swap their Trent 1000 engines around the fleet dependant on age.

EASA has issued an airworthiness directive affecting Rolls Royce Trent 1000 engines. Photo: Tom Boon – Simple Flying

The Trent 1000 engine series didn’t have the best of years in 2019. In fact, the engine hit the headlines a fair few times for a variety of reasons. A number of Boeing 787 aircraft received significant downtime as their engines were repaired. In turn, this led to carriers having to fill gaps in capacity. While Virgin extended the life of its A340s, British Airways wet-leased A340s.

What’s the latest?

According to the airworthiness directive, a number of Trent 1000 engines have been experiencing surges. The directive states that this has particularly affected engines which have experienced more use. These have more flight hours and engine cycles. Rolls Royce is reportedly still investigating the cause of these occurrences.

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EASA’s airworthiness directive suggests that there is a possibility that both engines could surge, resulting in a dual engine failure. If this were to occur, the aircraft would be left with no power to keep it in the skies. This, in turn, could have devastating consequences for both those on the ground and in the skies.

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2019 wasn’t the best year for the Trent 1000 engine which powers the Boeing 787. Photo: Tom Boon – Simple Flying

A Rolls-Royce spokesperson told Simple Flying:

Due to a higher than expected rate of engine surge events on a limited population of engines, we are taking action to ensure the continued operation of this fleet. This action has been agreed with EASA and is now mandated in an airworthiness directive while we further investigate root cause. We will work closely with customers to support any changes to service management this may require.

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So, what’s the solution?

EASA has shared a solution to the potential issue through an airworthiness directive. Instructions for completing this have come from Rolls Royce in the form of a Non-Modification Service Bulletin. This has instructed 787 operators to “de-pair” their engines. But what does that mean?

In essence, the point of de-pairing engines is to try and remove any commonality that may exist between an aircraft’s pair of engines. The risk of engine failure appears to be tied to the age of the aircraft’s engine. This principle is at the center of the airworthiness directive.

British Airways had to wet-lease an Airbus A340 to cover for aircraft affected by the Trent 1000 issues. Photo: Tom Boon – Simple Flying

Rolls Royce’s non-modification service bulletin instructs operators to put engines with different ages on a single aircraft. The thought is that if an older engine does fail, for whatever reason, it would have a younger engine as a back up to get you down to the ground safely. This is as the issue is thought to be more prevalent in older engines. As a result, it is possible that one aircraft with two older engines could suffer a dual engine failure.

According to Flight Global: “Trent 1000s with over 24,000h or more than 8,000 cycles cannot be paired with a similar engine, but can be paired with engines which have fewer than 17,000h and 5,500 cycles.” When the airworthiness directive goes into force, operators will have 30 days to make the necessary changes.

What do you make of the Trent 1000 airworthiness directive? Let us know your thoughts in the comments!

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Richard

Good idea in the short term RR need to sort out the problems. This is not a Boeing problem. Also customers should have a choice of manufacturer.

TonytTDK

Seems like an eminently sensible requirement from EASA.
Of course, if Rolls-Royce could actually resolve the problem, it would be a far better solution to the problem.!

top fatcat

Total Rubbish decision. If an engine is likely to fail at 8000 cycles, why not also at 5000 cycles?
Obviously the engine has a problem which RR has yet to uncover.
Until RR does this, the engine should be deemed not airworthy, totally.

BARRY

Sounds like yet another Boeing aircraft needs grounding until this problem is fully resolved. We don’t want aircraft dropping out of the sky due to fuel engine failure.

Don Hoare

An a an Aircraft Maintenance Engineer I disagree with R&R’s decision. They know the components that are wearing and failing. The engines should be removed at a low time and repaired. I think it is a parts availability issue and they are buying time. Swapping engines can create other issues… Read more »

W Fleig

As long as carriers are allowed to maintain these engines ” On Condition” the problem will likely continue. Obviously there is a correlation of cycles/ hours with frequency of failure. When an engine enters the danger zone it needs more frequent monitoring. In today’s world engine parameters are routinely tracked… Read more »

Wambulwa

This is not a solution. The Roll Royce should get the rootcouse of engine surges. EASA this is not safe. Who told you the young engines can not surge’?! you are only going by static’s and may be trends but not getting the Root cause, and that AD does not… Read more »

Jose A Garcia

Disaster waiting to happen. For public safety, engine mtbr should be reduced to short of established mtbf.

Harry Cix

Are we getting any closer to matter transfer? This defying gravity stuff is for the birds, not planes. This arcane method of travel is doomed to eventual failure; gravity has no mercy.

Gary

Why are they only failing on the Boeing 787 and not on the Airbus aircraft as well

Maintenance Man

if “it” is on a Boeing Aircraft, IT IS A BOEING PROBLEM. This is an EVOP certified aircraft requiring 99.999 reliability. Based on this proposed AD, reliability should be re-addressed!

Josh

In response to this comment… “If an engine is likely to fail at 8000 cycles, why not also at 5000 cycles?” Compressor surge margin reduces with engine life as compressor liners and blades wear. There is therefore a time (or engine cycle) basis to the risk of surge. It will… Read more »

Aizad Sayid

I just hope that aircraft manufacturers don’t start compromising beyond a certain point in shortening gestation period that is required to fully understand and test new technology. Aircraft can’t be produced with “running repairs” that take place with windows 10 patches and fixes after rollout! Aircraft engines have been taking… Read more »

Mark

pathetic.knee j**k response to cover their own arses.RR should supply and install a brand new engine for each dodgy one supplied when airplane made.Absolute nonsense for operators to now have extra workloads.RR..face up n man up to your rushed design of the engines and compensate and keep the Boeings safely… Read more »

Don

Being an engineer thsi makes perfect sence , your mitaligating the failute rate of a older engine and mix that with a much younger engine sonthat both wont fail. Its not perfect but its a step in the right direction. Preferably you travel on newer aircraft in any case

Martin Mukonje

This is a welcome directive, any form of prevention of a major air crash is commendable

Mark Petry

The ETOPS certification is largely based on the excellent reliability of these engines. If the Trent 1000’s IFSD rate is rising based on total hours, does that not throw the certification into jeopardy?

F P Weeren

Gary, the B787 is the only aircraft using the Trent 1000. The A340 used the Trent 600, the A380 uses the Trent 900.

Fpweeren

Gary, the B787 is the only aircraft using the Trent 1000. The A340 used the Trent 600, the A380 uses the Trent 900.

Otto Toot

Gary, the B787 is the only aircraft using the Trent 1000. The A340 used the Trent 600, the A380 uses the Trent 900.

Otto Toot

Gary, the B787 is the only aircraft using the Trent 1000. The A340 used the Trent 600, the A380 uses the Trent 900.

James

It makes sense but it also sounds like a “stopgap” fix. RR need to sort out the engine issues rather than play pairing games mixing old and newer engines. Doing so didn’t eliminate a dual engine failure, it just improves the odds of it not happening.

James101

It makes sense but it also sounds like a “stopgap” fix. RR need to sort out the engine issues rather than play pairing games mixing old and newer engines. Doing so didn’t eliminate a dual engine failure, it just improves the odds of it not happening.

JFP

This is a cross between a cheap band-aid and playing Russian Roulette with an u*i. Really bad idea. Especially with ETOPS certification. Or, does that now become irrelevant?

Rennie

Sounds pretty scary really. Mixing up engines in the hopes that only one of them will fail hardly sounds like a “safety first” culture at work.

Harry Cox

Why is it that Boeing is the only manufacturer using this engine? Could it be that the new McDonald Douglas run Boeing spec’ed out an engine that would be cheaper to enhance the bottom line just as they hired $5 an hour, offshore software designers to bring the 737MAX in… Read more »

Ian

Sounds like levelling out t****t surge…easy to repair.
Lots of downtime and yes, de-pair is a reasonable short term solution. Look at software issues.

William Pereira

Rolls Royce has a duty to provide flawlessly operating power plants to its customers. Boeing was an idiot by not dual sourcing its power plants like on the 757. How stupid.

Regan

The Trent 1000 is a disaster waiting to happen, already effected so many airlines around the world. Rolls Royce needs to pull their heads out of the sand

John

People before profits. Ground the 787. FAA and EASA do the right thing. Lives are on the line.

Paul m

Barry states the 787 should be grounded. Is Barry aware that the 787 is also GE powered. Perhaps Barry you should get all the facts

High Mile Club

Once again, ignorance and refusal to do research is clear here. For those who refuse to use google or whatever is their preferred search engine, the 787 has TWO engine options: The RR Trent 1000 and… Wait for it… The General Electric GEnx. Most 787s flying today use the GE… Read more »

Jah

Remove the engines at 8000 cycles 20.000h and replace with new or reconditioned engines. All planes with over that limit should be grounded

Jay

Remove the engines at 8000 cycles 20.000h and replace with new or reconditioned engines. All planes with over that limit should be grounded.

Raptuno

This is what makes everyone wish the universal pylon of the 7E7 concept survived