Nearly three years after its first delivery, the Airbus A320neo family is, in terms of sales, an undeniable success. More than 60 operators put the aircraft into service.

However, a significant number of them have had to deal with engine performance problems or aircraft delivery delays. Perhaps in part because of this, several operators have declined to be interviewed by FlightGlobal about their service experience with the narrow, motorized body.

Nevertheless, when it comes to fuel consumption, the device seems to excel. When Lufthansa's Klaus Froese – managing director of the Frankfurt Air Center and active line captain – sweeps the instruments from the A320neo cockpit to a cruising altitude, he often turns to the "really fantastic" indications of fuel flow, describing these figures as "remarkably different". "From what he's used to seeing on the company's older A320s.

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The fuel flow of an engine is usually measured in thousands of kilograms per hour, but the figure for regenerated narrow bodies often falls to three digits. "You remark [the fuel savings] when traveling by plane – not just in terms of accounting at the office, "says Froese.

After choosing the Pratt & Whitney PW1100G turbofan engine for an initial fleet of A320neo, Lufthansa became the aircraft launch operator in 2016, after Qatar Airways had declined its role. The carrier's decision in the Middle East was linked to technical issues related to the GTF plant.

Lufthansa has decided to equip about half of its A320neo fleet on order with CFM International's Leap-1A reciprocating engine. Shipments of these aircraft are expected to begin in 2021.

MORE POWER, LESS FUEL

From the pilot's point of view, the new engines provided a quieter and more comfortable driver's cab. In addition, minor information was provided to the cockpit information and navigation in the flight management system menus. According to Froese's review, the new Twinjet is "fun" for the drivers, as it offers more thrust and better climb performance than the A320ceo.

This view is shared by AirAsia, which, after presenting its first Leap-powered A320neo in 2016, says the plane "feels more powerful" [to pilots], and has a distinctive engine sound. "The airline notes that the operations of the Airbus A320neo are" very similar to those of the Airbus A320ceo, with only slight variations in standard operating procedures ".

Lufthansa said its A320neos fulfilled P & W's 16% fuel economy promise compared to previous-generation aircraft.

The airline has calculated that, on a per seat basis, its 180-seat Neos offer a 21% fuel economy over its older A320s, which can accommodate 168 passengers. Flight Fleets Analyzer shows that the oldest aircraft in the family fleet of A320 aircraft, which has about 180 people, are 29 years old and are powered by the CFM56-5As.

Avianca told FlightGlobal that its A320neos equipped with Leap offered 15-20% lower cruising fuel consumption than first-generation vehicles, which allowed the Colombian carrier's technical director, Adolfo Carvajal, to call it "Huge" on flights of more than 4 hours.

However, the introduction of Airbus' updated "bread and butter" aircraft has been marred by numerous engine problems – mostly related to the GTF – and by delivery delays resulting from blockages of production and supply chain.

All new aircraft are affected – to varying degrees – by start-up problems. This has made the situation of the A320neo more difficult – for operators, Airbus and suppliers – it is the high production rate at which the conversion of the Airbus A320ceo takes place.

When the previous generation of engines was introduced in the 1990s, for the A320 and Boeing 737, problems that could have arisen during the initial production and the period in service have affected a much smaller number of aircraft and operators.

Not only was the exposure to potential problems much less important, but it was probably easier for manufacturers to incorporate changes to the production process without creating significant bottlenecks and delaying production. delivery delay.

STARTING QUESTIONS

The initial operations of Lufthansa and other airlines with the GTF have been seriously affected by a rotor arc problem which has resulted in an increase in start-up times.

While the A320ceos take about 2 minutes to start both engines, the procedure initially took 6 to 7 minutes on the Neo because the GTFs were centrifuged for several minutes – without fuel injection – to reduce the rotor temperature difference between the two engines. cold and hot sections.

The extended start-up time has created a headache for Lufthansa, particularly at its Frankfurt site. Germany's largest hub having dead-end bays with multiple aircraft stalls, the departing Neos have blocked other flights and disrupted the traffic flow of the plane. ;airport.

P & W reacted by making a number of changes in 2016, including software modifications, reinforced shaft bearings and the introduction of a dual-cooling push button in the cockpit, allowing pilots to gain a little of time while starting to wind the second motor during the first one. was still in the boot process.

Froese acknowledges, however, that Lufthansa has struggled for "a long time" with the start-up problem and that this problem has not been solved before the end of 2017. "It is really embarrassing for an airline that is fighting for productivity gains of wasting time, "he says.

Startup times have been reduced to what it calls a "roughly acceptable" level of 2-3 minutes, depending on weather conditions. But Froese notes that starting the Neo takes even longer than that of the A320ceo.

P & W stated that, although the GTF's start-up times were initially "longer than expected", they are now, as a result of the changes, "in line with industry standards". The manufacturer notes: "Because the [GTF] It works longer than the engines of the previous generation, the dissipation of the thermal gradient in the motor may take longer before starting. "

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Avianca, for its part, gives a glowing glimpse of its A320neo-family jets.

"Our entry into service was fantastic," Carvajal said, citing the aircraft 's energy efficiency, the quietness of its Leap engines and the positive reception reserved for passengers. "All [these] the variables gave him an excellent entry into service with our company. "

Receiving its first Neo in 2017, the carrier and its affiliates under Avianca Holdings have nine A320 family jetliners (seven A320neos and two A321neos) in service, with about 120 other aircraft to follow through in 2025. Carvajal acknowledges that a number of Neo deliveries have been delayed by the bottlenecks of Leap production, but describe the delays as being largely insignificant.

AirAsia, meanwhile, indicates that some of its deliveries of A320neo have been delayed – mainly for the same reason – but that the majority of them have arrived on time. Flight Fleets Analyzer shows that the AirAsia operation in Malaysia has 23 A320neos in service and 372 other A320neo jets are on order. Thai AirAsia, a wholly-owned subsidiary of the group, has 11 Neos on duty. The delivered aircraft worked well in service, says AirAsia.

In addition to reducing fuel consumption, oil consumption was halved compared to the CFM56-5B and servicing requirements were also reduced, the airline said.

Until now, the only major problem encountered in service on the section is the premature degradation of a thermal barrier coating on high pressure turbine fairings. To solve the problem, CFM changed the coating application process in 2018.

AirAsia also experienced reliability issues with starter air valves, fuel injectors and pressure sensors, antifreeze valves and variable purge valve actuators. But the problems have been or are being solved, says the airline. He adds that the reliability of the technical dispatch of his Neos is "comparable" to that of his CEOs.

VIBRATIONS

Lufthansa's experience in service with the Neo has resulted in a series of technical problems – mainly related to engines – separated by periods of relative stability. The last issue deals with the vibrations of the high-pressure rotor shaft (N2) observed on several PW1100G engines. Froese says that the vibrations are not noticeable by the occupants on board, but that they have been picked up by the engine's instruments.

According to P & W, less than 2% of the plants in service were affected by "transient engine vibrations". The automaker did not reveal the source of vibration and told FlightGlobal in December that engine tests were still underway to understand the problem. No incidents of engine shutdown in flight has been associated with vibrations, P & W stresses.

According to Lufthansa, the vibrations – which have been recorded over time as the engines have matured – generally occur during the early phases of flight after take-off.

While P & W forces operators to replace engines as soon as a certain vibrational force or event frequency is reached, Lufthansa has had to remove several power plants from the wings. "It's something we've been busy with over the past few months, because we have repeatedly [vibration] range where we had to replace the engines, "says Froese.

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He notes that it would be much easier to deal with the operational challenges posed by the GTF if the supply of spare engines was more abundant. Lufthansa has often worked for long periods without a GTF available at its base, says Froese. Although its fleet has spare engines for other aircraft in its fleet, the carrier tends to receive spare FGFs from P & W only in the case of a ground plane scenario.

P & W is caught between two opposite demands in terms of engine power: on the one hand, it must adhere to the Airbus ramp-up plan (and reclaim previous delays), and on the other hand On the other hand, it must provide spare engines to end-users who are increasingly frustrated.

Airbus says that after the suspension of GTF deliveries for eight weeks until April 2018 due to a faulty seal of the high pressure compressor, the aircraft manufacturer decided with P & P W prioritize engine deliveries to airlines – to support aircraft in service – rather than assembly lines for new aircraft.

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For airlines, performing daily fleet operations without spare engines is a particular problem.

Froese describes the supply of spare engines as a "very dynamic company", to which Lufthansa has assigned its staff to "protect our interests". And while engine replacements for the vibration problem are – to some extent – predictable, he said the aftermarket engine situation remained "very difficult" despite "intensive discussions" with P & W.

The manufacturer says it is in the process of strengthening the supply of spare engines of the operators and pool of P & W and increase the activity of MRO in order to "meet the expectations Spare engines are assigned to the best of our ability to minimize operational disruptions. " P & W adds: "This effort will continue until 2019."

The engine maker has qualified 2018 as a "catch up year", with GTF and MRO production almost doubling compared to the previous year. "We are reaching the maturation of production facilities and MROs faster than any other program in our history and, obviously, demand continues to grow," said P & W.

"ABSOLUTELY UNSATISFACTORY"

Lufthansa refuses to indicate a technical reliability figure of its A320neo operation – citing a limited fleet – but asserts that this figure is clearly below the target of 99.8% set by the entire the fleet of the company. Froese claims that Neo's technical reliability has not improved significantly since the entry into service.

Flight Fleets Analyzer reports that the Star Alliance carrier has 15 A320neos in service and another 109 aircraft in the A320neo family ordered, including 40 A321neos. At the end of September, the planes of Lufthansa's Neo fleet, with 13 planes, were operating around 20% less time per day than the carrier's A320ceos, the airline said. On average, Neos worked on average 73% per day for Ceos of the same age and 92% for the older Lufthansa Ceo.

At the same time, Neos' unplanned ground flights were five and a half times longer than those of the same age group, while maintenance costs were about 60 percent higher, the airline says.

Noting that re-motorized aircraft are expected to become the central pillar of Lufthansa's European operations, Mr. Froese describes the airline's airline service experience with the A320neo as "utterly unsatisfactory", despite an "up-and-coming" interview. intensive". He acknowledges that Airbus and P & W have been available to discuss the operator's concerns, but said: "In terms of [operational] results for the engines, we would have liked something else. "

P & W estimates 99.91% reliability of Neo Fleet engines in service, powered by GTF, which, he adds, "compares favorably with other early stage engine programs" .

Responding to Lufthansa's comments on Neo's relatively low utilization and major maintenance efforts, P & W said: "There are no operational restrictions on the PW1100G-JM that would reduce this level of performance." Instead, the builder suggests that low use could be the result of individual circumstances as "operators make their own decisions regarding the structure and use of aircraft routes".

P & W insists that the GTF is "able" to meet the operational levels of the previous generation of the International Aero Engines V2500 – the US manufacturer is the largest shareholder of this program – and that "we are seeing a increased levels of use "of the GTF.

Airbus acknowledges that P & W still needs to provide upgrades and that the efforts to modify the engines in service will continue until 2019, but adds that GTF technical problems have been "largely solved". The reliability of the operational deployment of the Neo fleet in service is "very close to the target" at 99.6%, said Airbus, adding that there was now "less disparity" between Ceo and Neos.

Regarding maintenance costs, P & W argues that if the V2500 operators have "benefited from 30 years of continuous improvement", the GTF is still "that at the beginning of its life cycle ".

The maintenance costs of the GTF will almost certainly be borne by P & W, as the engines are still under warranty and the majority of the fleet in service is covered by one-hour maintenance contracts with the manufacturer. But, of course, airlines face additional disruption charges when aircraft are not usable – or are not available initially due to delivery delays, which have affected many Neos operators operating on the market. times in Leap and GTF.

LATE DELIVERY

The interruption of last year's GTF deliveries and a distinct delay in Leap's parallel production (resulting in bottlenecks in the supply chain) led to a build-up of engine-free Neos on Airbus. This peaked at more than 100 aircraft in June.

Although this number has since been reduced, Airbus said in December that the order book "would not be fully eliminated by the end of the year". The aircraft predicted that fewer than 10 aircraft would be conducted until 2019.

After revising its production targets after the delivery break in 2018, P & W is in the process of giving up the engines under the new plan, Airbus said. Meanwhile, the aircraft said that CFM had not "completely" caught up in December with its plan to overcome the backlog of production by the end of 2018.

Airbus acknowledges that additional efforts are needed to stabilize and increase Neo's production, but says it is on track to reach the target of 60 deliveries a month by mid-2019.

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Hawaiian Airlines is one of the operators involved, which has had to postpone new link plans and reinstate a 767 retirees following several months of blocking the A321neo.

"The main challenge we faced was late delivery," said Peter Ingram, Hawaii's Managing Director, FlightGlobal, noting his frustration at the freezing of GTF deliveries. "It was a major disruption of our [2018]and we had to make some important changes to the schedule. "However, Ingram has repeatedly praised the operational capabilities and efficiency of the A321neo."

In September, Lufthansa had received 13 of the 20 A320neos whose operation was planned with the carrier at that time. As new aircraft did not arrive, the old equipment could not leave the fleet as planned.

But since previous maintenance work was geared solely to keeping the old aircraft in service until their scheduled departure, the airline had to make up for maintenance, which, Froese says, "often breathes new life into the airplanes. that you will not use ".

He added that Lufthansa had so far managed to avoid having to lease an external capacity to operate its program, despite the late arrival of new aircraft. But he says that the carrier "gets by on a monthly basis" with the available fleet and that the situation is "at our economic disadvantage".

In order to mitigate the effects of Neo's delivery delays, Lufthansa ordered nine additional A320ceos, which were scheduled to arrive between December 2018 and the summer of 2019, but were not part of the original fleet plan the company.

If the price of fuel rises again as we have seen for much of 2018 – before easing in the fall -, the fuel economy benefits of Neo will become more pronounced than during the first three years of operating the type.

Mr. Froese believes however that the overall economic benefits of the A320neo should be weighed against the cost of acquiring the aircraft (Airbus announces a $ 9.6 million difference between the two generations A320) and operational performance over a long period.

He suggested that any fuel savings could be offset by additional costs generated by maintenance or reliability issues. "The engines are very expensive [and require] a lot of talk, I would say, but [have] much lower fuel consumption. I'm curious to see how [overall] the bill looks like in 10 years. "

With a wink at the price of fuel, he shouts: "God keep us that it falls."

According to Froese, Lufthansa's main lessons from the introduction of the A320neo have been to allocate more spare capacity and expect further disruption during major operational changes.

He believes that although airlines are using more of their assets, the risks associated with the introduction of new technologies or processes are not sufficiently taken into account in the economic analyzes carried out by operators for such projects.

Noting the capacity limitations in the air transport sector – among carriers, manufacturers, airports and air traffic control providers – Froese said: "We are seeing it everywhere … The buffers in the system of production of aviation have become so thin that minimal disruption is enough to disrupt it considerably.

"If we want to have more stable operations, we need more buffers and reserves," he adds.

Unsurprisingly, Airbus offers a brief summary of key learnings, clearly addressed to engine builders. The aircraft says it is necessary to have "more advanced engine tests in the OEM engine test cell and [Airbus’s] flying test bench ".