All About the A380's Engines

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Interesting reliability numbers, following this post about the A380 is an article about the 787 and some issues with it's engines.

A380 Engine Reliability High But Spare Parts Risk Arises

Engine MRO for mega-transport should generate about $4.2 billion in 2017-26

 

Aviation Week’s 2017 Commercial Forecast projects maintenance spending on the Airbus A380’s Engine Alliance (EA) GP7200s will total nearly $4.2 billion in 2016 dollars for about about 800 MRO events in 2017-26.

By the end of September 2016, 118 A380s were powered by variants of the GP7200, representing 60% of the fleet. GP7200s had accumulated more than 6.6 million flight hours and 867,000 cycles.

EA CEO Dean Athans says the GP7200 has been quieter, by 0.8 Effective Perceived Noise dB, than the competing Rolls-Royce Trent 900. He reports dispatch reliability of 99.3% despite many short flights in hot, sandy environments. He notes the engine saves up to $500,000 per A380 per year on an average route and has a payload-range advantage worth up to 22 passengers on long-haul routes.

 

Air France’s GP7200s have a rate of inflight shutdowns of 0.001 per 1,000 flight hours. Credit: Air France Industries-KLM Engineering & Maintenance, Patrick Delapierre

 

Athans estimates the GP7200, with high-pressure turbine upgrades introduced in June 2014, can operate 3,500 cycles before its first shop visit. This estimate was validated by testing in May 2015. Upgrades have improved time-on-wing and average $100,000 in fuel savings per aircraft-year, according the joint venture between General Electric and Pratt & Whitney. Targeted mean time to the first shop visit is around 2,500 cycles, without the high-pressure turbine upgrades. Joseph Martin-Ginolhac, EA engine manager at Air France Industries-KLM Engineering & Maintenance (AFI-KLM E&M), expects time-on-wing of 2,500-3,000 cycles until the first shop visit, depending on the high-pressure-turbine configuration. 

Its network shops are targeting 80-90-day turnarounds for a typical first shop visit in 2017. Athans says operators and EA have adequate spares for the GP7200, and the company will build three spares in 2017. Customers have spare fans and propulsors, which together make up reserve engines. Airlines need fewer fans than propulsors, and propulsors require less space and are easier to transport. EA also maintains a pool of fans and propulsors.

 

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GP7200s can be overhauled at GE Wales in Cardiff, AFI in Paris and Emirates’ Engine Maintenance Center in Dubai. Pratt & Whitney Eagle Services Asia in Singapore is developing MRO capacity for the GP7200.

Martin-Ginolhac says Air France’s GP7200s are performing well, with a rate of inflight shutdowns of 0.001 per 1,000 flight hours, aborted take-offs at 0.0016 per 1,000 departures and dispatch reliability at 99.91%. 

On-wing maintenance for the GP7200 has been substantial with many inspections, such as those for Nozzle Guide Vane 2s, as well as borescope checks required under an airworthiness directive. Other required inspections are on high-pressure compressors, low-pressure turbines, borescopes for design issues on Disk 6 and mandatory high-pressure case checks for life extension. Air France needs four inspections per week for its 10 A380s. There are also modifications on sensors, fuel pumps, starters and deflectors.

On Nov. 1, the FAA issued Airworthiness Directive 2016-22-11, which superseded ADs for GP7270s and GP7277s with certain high-pressure-turbine Stage 2 nozzle segments. Inspections are required and, if burn holes are detected in nozzle segments, affected nozzles and other parts must be removed. The new AD was effective Nov. 16. The FAA estimates inspections require 2 hr. per engine and that parts could cost $500,000 for each powerplant. 

Unscheduled removals sometimes have altered this interval due to baffle-plate failure, crack indications for the low-pressure turbine shaft and the condition of the high-pressure compressors.

A full shop visit takes 90 days, and AFI-KLM E&M can conduct up to 10 per year. Air France has enough spares and EA enough lease engines to support overhauls now. But Martin-Ginolhac worries that the end of new GP7200 production will put availability of sufficient spare parts at risk in the long run. “For the future, provisioning of parts will be a key issue.”

Predicting the timing of MRO is tricky. Using utilization rates and standard intervals between events, Aviation Week’s Commercial Forecast estimates GP7200 maintenance events ranging from hot-section inspections to full overhauls at 72 in 2017, a low of 16 in 2018, a ramp-up to 136 in 2023 from 80 in 2019, before dipping back to 72 in 2024. Expected events in the last years of the decade will be 104 in 2025 and 60 in 2026.

Maintenance spending forecasts follow the same pattern, starting at more than $300 million in 2017, dropping sharply in 2018, then recovering to nearly $400 million in the next several years.

But EA’s Athans forsees no dip in 2018 but rather a steady increase in maintenance spending over the next 10 years. EA works with airlines to stagger shop visits to avoid a bow wave and has pulled some GP7200s without upgrades to conduct proactive maintenance and upgrade them. 

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ATSB: Part Failures Behind 787 Engine Incidents

Dec 14, 2016John Croft | Aviation Daily

 

 

WASHINGTON—Part failures were the root cause of two Boeing 787 engine incidents for Jetstar Airways and Scoot Airlines in August and September 2016, respectively.

Just-released preliminary reports on both incidents by the Australian Transport Safety Bureau (ATSB) reveal that fixes to both issues have been deployed, a modified transfer gearbox component for the GEnx-1B engine based on the Jetstar 787 incident, and new hydraulic hoses in the nacelle as a result of the Scoot incident.

Of the two, the Jetstar incident was the more serious, in that it resulted in an in-flight shutdown of one engine and a diversion. According to the ATSB preliminary report, Jetstar Flight JQ12 was about two hours into its flight from Tokyo to Queensland, with 11 crew members and 309 passengers on board, when the crew received an electric-generator-drive fault message on the No. 2 generator on the right engine.

The generators, which power electrical systems on the engine and aircraft, are run by a mechanical shaft connected to the rotating portion of the engine. The crew followed the appropriate checklist and disconnected the generator from the engine, powering up the auxiliary power unit to take its place. The fault message is linked to the engine-debris monitoring system, which was detecting metal chips in the engine oil.

About 30 min. later, at a cruise altitude of 40,000 ft., the crew received messages that the right engine oil pressure was low, faults that resulted in the shutdown of the right engine. The crew declared an emergency and flew to Guam, the nearest airport, 200 nm south of their position.

On the ground, a maintenance crew found “a large quantity of oil throughout the engine, and a considerable amount of metallic debris within the engine oil system,” according to the ATSB.

The source of the leakage and debris was a fracture in the housing of a transfer gearbox, which is connected to the engine by a mechanical shaft. GE determined that the failure “was consistent” with a mechanical resonance issue addressed by a service bulletin issued in March.

The fix included changes to the gearing to dampen vibrations. Jetstar had begun the replacing the components in its GEnx engines, but had not completed the work on the incident engine, as it was in the lowest-risk category due to its low time. The carrier, in response, modified its service-bulletin compliance time, making it a priority to implement the service bulletin on at least one engine on each 787. All modifications were completed as of November, according to the ATSB.

The Scoot 787 incident occurred when the aircraft used maximum reverse thrust during its landing in Melbourne after a flight from Singapore, according to the ATSB preliminary report. Controllers called the pilot, saying they had seen smoke coming from the aircraft’s right engine, although there were no anomalous indications in the cockpit, nor any evidence of issues externally on the engine compartment.

Mechanics later found that a damaged hydraulic hose in the right engine pylon hydraulic bay had leaked hydraulic fluid, likely causing or contributing to the smoke (The Rolls-Royce Trent 1000 also naturally emits smoke in some cases due to incomplete air/oil separation, according to the ATSB).

Boeing analyzed the issue, determining a root cause and identified the population of hoses that might be affected, alerting airlines of the issue. The ATSB said Scoot identified which hoses in its fleet might be affected and ordered replacement parts.