In-service report - Climbing the learning curve

The Boeing 717 is in service with seven airlines around the world, but is the new arrival living up to expectations?

Guy Norris/LOS ANGELES Max Kingsley-Jones/ATHENS Andrew Doyle/SYDNEY

Eighteen months after the first Boeing 717-200 entered service with Atlanta-based AirTran, 61 aircraft have joined the growing worldwide group of operators which currently includes eight airlines and two leasing companies.

More than a third of the current fleet is in service with AirTran which, as the former low-price carrier ValuJet, originally launched the aircraft in October 1995 as the McDonnell Douglas (MDC) MD-95. After struggling against the threat of cancellation, the MD-95 re-emerged as the 717-200 in January 1998, following Boeing's take-over of MDC the previous year. Not including a soon-to-be-finalised order for 20 from Midwest Express, the aircraft has now attracted 154 firm orders. Sales, however, continue to be slow and Boeing has announced that it is laying off 600 workers from the Long Beach plant where the 717 is built.

"We have 22 aircraft now, and will have 25 by September," says AirTran senior vice-president operations Steve Kolski. By the time the 32nd 717 arrives in February 2002 the type will account for more than 50% of the airline's total fleet, he adds. The 717 is replacing the elderly DC-9-32, which provides the aerodynamic and structural blueprint for its otherwise all-new successor. AirTran is speeding up the DC-9 replacements after early experience with the 717 showed the Rolls-Royce BR715-powered twin was 26% more fuel efficient than the older jet. "We took it expecting to get 22% as advertised, so this is useful, particularly with today's fuel prices," says Kolski.

AirTran's highest time aircraft has "around 5,000h" flight time, and 14 have already passed through their first "C" checks. "These are three-day events, versus the 25 to 31 days on a DC-9," Kolski says, adding that no "D" checks are scheduled for the aircraft as the maintenance programme calls for a "segmented D-check" in which elements of the more thorough inspection are undertaken at each "C" check interval.

Constant improvement

The in-service fleet is meanwhile showing constant improvement in terms of 'mission completion' and on-time departures. Dispatch reliability, measured in terms of departures within 14 minutes of scheduled time, was 98.4% in April versus the airline's goal of 97.3%. "That's generally between 5% and 6% better than where we have been," says Kolski. "Completion factor" for April was 99.8% against a target of 99.7%. "This means that only 0.17% of 717 departures were cancelled for mechanical reasons," he adds.

The figures reveal swift maturity for a product that gave AirTran "a rough couple of months" in its early days. Most of the mechanical issues cropped up in the aircraft's first winter season which unearthed ice ingestion problems with the design of the auxiliary power unit inlet, (APU) the air-cycle machine and engine starter (see The manufacturers' view).

However, Kolski says "the number one break-in problem was software issues that created erroneous fault codes. Boeing developed a second certification set of software which largely cured it, but it caused us a lot of operational problems at first." The problems manifested themselves as false warnings about engine status, control column disconnects as well as flap and slat positions. The only cure was a time-consuming power down/power up of the aircraft. "The mechanic would basically have to re-boot the aircraft," he adds.

The most notorious of early faults was the failure of a power conversion distribution unit (PCDU) which led to the failure of the main flight deck displays on more than one occasion. The failures, which forced the crew to resort to standby instruments, were traced to moisture dripping into the PCDU which is located in the EE (electrical equipment) bay beneath the flight deck, aft of the nose gear undercarriage bay. Although the incidents resulted in a temporary night-time flying restriction on the 717-200, the problem was quickly solved by changes to the connectors, the installation of a drip tray over the top of the box and sealing of the flight deck floor. "We had a ton of Boeing reps here initially, and that was appropriate for the time," recalls Kolski.

A lift for AirTran

Overall, however, the 717 has been good news for AirTran employees who needed a lift after the May 1996 Florida crash of the ValuJet DC-9 which almost led to the collapse of the carrier, and prompted the name change. "It has provided a spark to the employees of the company. It's a very quiet aircraft, its fuel efficiency is beyond our expectations and I really can't say enough for it," concludes Kolski.

Another US operator, Hawaiian Airlines, is the latest newcomer to the 717 fold. It inaugurated services between the six islands of its Pacific home in February 2001. The airline operated three by the start of May and expects to have all 13 on firm order in service by year end, representing the fastest fleet build-up of any operator to date. Some initial delays to services have been mostly attributed to "our maintenance staff getting used to the aircraft rather than the 717 itself," says Hawaiian.

The airline's short-haul network of inter-island routes makes this the most intensive duty roster for the type anywhere in the world. By late April, the first three aircraft were averaging 13.1 cycles per day, with an average ground turn around time of only 28 minutes. Dispatch reliability was "around 99%" says Hawaiian, despite the intense operations, and the airline says it is "very happy" with its new aircraft. Given the high year-round temperatures in which its aircraft operate, the airline is not faced with the oncoming threat of winter that is driving Boeing's urgent APU inlet, engine starter and air cycle machine modification effort. With residual values in mind, however, Hawaiian is having the air cycle modification retrofitted on delivered or completed aircraft. It will also have the new APU inlet design on all subsequent deliveries but will not be upgrading with the engine starter change.

Across the Pacific in Australia, Impulse Airlines put its first Boeing 717-200 into revenue service at the beginning of May 2000 and currently operates eight of the type, making it the twinjet's largest operator outside of the USA. Another five are due to arrive by the end of this year and Impulse plans to increase its fleet to more than 25 717s by the end of 2002, though this may be reviewed after the carrier decided to pull off Australian domestic trunk routes and fly regional and leisure routes on Qantas' behalf instead.

Its first three aircraft were taken on lease from Germany's Bavaria Leasing, and two of these were in desert storage at Kingman, Arizona awaiting customers when Impulse selected the 717 for its expansion onto mainline routes.

"We used these two aircraft as operational training aircraft for our first group of engineers through FlightSafety Boeing Training International (FSBTI)," says Impulse director of engineering Peter Shepherd. The third was already on the production line at Boeing's Long Beach plant in California.

Bavaria had defined the specification of these initial three aircraft and omitted certain equipment included on the rest of the Impulse 717 fleet such as autobrakes, Airborne Communications Addressing and Reporting System (ACARS) airline datalink and a flight data acquisition management system (FDAMS).

Boeing-funded initial pilot training on the 717 began in February last year when an Impulse training captain and pilots from Australia's Civil Aviation Safety Authority (CASA) travelled to the USA to begin familiarising themselves with the aircraft. The first intake of Impulse pilots started training with FSBTI at Long Beach the following month.

Lack of simulator time

According to Impulse director of operations Terry Wilson, the availability of 717 simulator capacity has been a concern for the airline. "That's been one of the principal limiting things for getting the crew we need trained," he says.

A simulator is available at Trans World Airlines' St Louis base, in addition to the devices installed at Long Beach. To ease the initial training burden Boeing provided six of its check pilots to Impulse to fly the line and help carry out the 50h of line supervision required to bring each of the carrier's own pilots on line.

Meanwhile, certification by CASA of the airframe for Australian operation was effectively a formality as Australia recognises US Federal Aviation Administration approvals as fully satisfying its own requirements.

Impulse put its first two 717s into revenue service on 5 June 2000, followed two weeks later by the third aircraft. The several weeks which separated delivery of the first aircraft and its entry into service were used to carry out simulated commercial operations to secure an upgraded air operator's certificate. This was required because Impulse had previously only operated smaller turboprop aircraft, and the 717 exceeds the 38-seat threshold adopted by CASA.

"That was probably our biggest challenge in the time we had available," says Wilson. "So we used those aircraft to run operational proving flights to our planned destinations.

"We were probably running three to four flights per week between Sydney and Melbourne where we were exercising the whole system," he adds. The trial covered everything from aircraft loading to maintenance record keeping, and the flights carried staff and other volunteers who acted as passengers, Wilson says.

Wilson and Shepherd drew heavily on their own experience during the CASA approval process as both are former employees of the aviation safety agency. Wilson used to be CASA's general manager with responsibility for airline operations and Shepherd was operations manager in charge of airworthiness requirements.

Impulse meanwhile enlisted outside help from other experts and former CASA employees to put together 717 operations and maintenance manuals that met safety requirements.

"We would never have achieved everything in such a short timeframe without some very good contractors that we used for doing the operations, maintenance control and procedures manuals," says Shepherd. "The dispatch reliability is still 99%." The eight aircraft now in the fleet are each spending an average of 2,850h in the air per year, Shepherd adds, which equates to a combined 9.4h of utilisation per aircraft per day.

For the first month of 717 revenue operations a technical dispatch reliability rate of 99.6% was achieved, Shepherd says. Each aircraft performed around eight flights and 8.5 flying hours per day with a standard turnaround time of 30min. He emphasises that that the few technical issues encountered have been relatively minor. However, there have been "some teething problems with the engines, and a large number of service bulletins (SBs) from Boeing," he says. "They are nothing dramatic but there are a lot of them."

Although a fix for the problem has been developed, modified gearboxes fitted to three engines have subsequently failed as well. Investigations into the first two have concluded that they were caused by technicians incorrectly installing the modified gearboxes, while the probe into the third incident, which occurred on an Impulse aircraft, is still under way. Impulse also suffered two failures of unmodified gearboxes prior to the introduction of the fix, but none has so far occurred in flight or led to inflight shutdowns. The other engine issues centred on problems with the inlet cowl and cracking of the compressor case.

Extended 'on wing' time

The BR715 turbofans powering Impulse's 717s have been de-rated to 18,000lb-thrust (80kN), compared with the standard 21,000lb to reduce operating temperatures and extend "on-wing" time between maintenance checks.

Boeing will also send a team to support Impulse when it performs its first 717 "C"-check, due when the fleet leader achieves 3,500 flight hours after approximately 15 months in revenue service. Though the work should normally take only four days to complete, "we've planned to have the aircraft on the ground for two weeks to address quality escape items and service bulletins," says Shepherd.

Impulse says its operations have benefited from Boeing's daily service reports that flag up incidents experienced by other 717 operators. "That helps us a lot," says Shepherd. "It gives us a good insight and helps us prevent delays if there are a spate of failures coming up."

Impulse uses the FDAMS fitted to the two aircraft it has on lease from Pembroke Capital and the three it has taken from Boeing to monitor the in-service performance of its 717s. The three Bavaria Leasing aircraft are to be retrofitted with the devices. Impulse and avionics supplier Honeywell signed an innovative Integrated Support Solution agreement to provide "power-by-the-hour" style spares support and it is thought the recent involvement of Qantas may help overcome financing issues that have so far prevented it from coming to fruition.

All eight of Impulse's 717s are flying with their autopilot vertical navigation (Vnav) capability de-activated until the five Bavaria- and Pembroke-owned aircraft receive a software upgrade, due in the next few weeks. The 717 was certificated without Vnav but the new software was completed in October. The three aircraft on lease from Boeing already have the new software. The software loads into the aircraft's flight control computer, bringing online a total of 18 improvements, and will also make available the aircraft's reactive windshear detection system.

However, one undesired consequence of the initially proposed software upgrade for Impulse was that it did not maintain an automatic direction finder (ADF) navigation functionality. "In Australia we can't do that, so we had to take some steps to make sure that it was included for us," says Wilson. "In Australia you are mandated to have ADF, even with GPS," he adds.

The 717's much lower than expected block fuel burn has been a major bonus. "We are doing 6-8% better than budget," says Wilson.

Olympic launch

Olympic Aviation, the regional arm of Greece's national carrier, was Europe's launch customer for the 717 and introduced the first of three aircraft last January. The acquisition of the 105-seater jet was a departure for the carrier - until then it operated only turboprop aircraft, the largest being its 68-seat ATR 72s.

"The introduction of the 717 was necessary for Olympic Aviation to stimulate the market and gain a new share of the regional sector," says the airline's chief executive, Petros Stefanou. The airline chose the 717 to execute a key component of its 1998-2003 business plan, which called for the creation of a second domestic hub outside Athens in the northern Greek city of Thessalonika. After introducing the twinjet on Olympic Airways flights from Athens in January 2000, they were redeployed to create the new Thessalonika hub three months later, which opened on 26 March 2000.

The airline has three 717s in service: two leased from Bavaria Leasing and the other from Pembroke Capital. One aircraft provides back-up for the other two. The aircraft fly an average of 11-12h a day on a network from Thessalonika to 12 destinations: Amsterdam, Berlin, Brussels, London (Gatwick), Munich, Paris and Stuttgart, as well as Larnaca in Cyprus and the Greek islands of Rhodes, Santorini and Crete (Chania and Heraklion). The aircraft is popular with passengers, with load factors running in as high as 90%. Stefanou says that the 717's introduction and the new hub have seen the airline achieve a 35% year-on-year increase in traffic.

Olympic Aviation's operations and technical staff are pleased with the 717's performance during its first 15 months of operations. The fleet's technical despatch reliability (TDR) has been running at over 99.7%, and Olympic recently received a congratulatory letter from Boeing for achieving an impressive TDR of 99.89% over 12 weeks.

Staff say that despite Boeing's relative inexperience in dealing with genuine regional airlines like Olympic Aviation, the US manufacturer has performed well. "They treat us like a large airline," says one of the senior flightcrew. "For Boeing, I think Olympic Aviation was a case study on how to work with a regional airline," says Stefanou. "It is very important that Boeing understands the problems that a regional airline faces."

Olympic's initial 717 crews trained on the simulator at Long Beach, and Boeing provided four instructor pilots who flew 50h of line training with Olympic pilots. The airline now has 16 717 crews, with each captain having more than 12,000h. It will start using the new FSBTI simulator in Miami next month, and is in talks with the training joint venture about installing a 717 simulator at its Thessalonika training centre.

Popular with pilots

As one would expect, with Olympic's 717 flightcrews coming from the turboprop fleet, the 717 has proved popular with pilots. "The 717 is powerful and fun to fly, and friendly to the pilot. There are no take-off restrictions out of Thessalonika," says Capt Alex Thanopoulos, director general of flight operations. Thanopoulos, who recently flew Greece's prime minister on board a 717 into the short 1,500m (4,900ft) runway on the island of Chios, says Olympic cruises the aircraft at M0.76-0.77 at altitudes of 31-33,000ft. Its longest sector is the 3h Thessalonika-Gatwick service.

Olympic is so far the only European airline with JAR-145 approval to carry out both line and heavy maintenance on the 717, which is undertaken in Thessalonika. The carrier recently completed its first 717 "C" checks with Boeing engineers in attendance, and hopes to develop third-party business with the manufacturer's support as Europe's 717 fleet expands.

"Bearing in mind it is a new aircraft, overall the product support has been satisfactory," says Olympic Aviation's general manager of technical operations, Nick Demenagas. However, the airline is pushing Boeing to make more effort in markets such as Europe where only a handful of 717s have been delivered. "There are few other carriers we can call upon for help, so the major vendors need to provide better spares support in Europe," says Demenagas.

The airline utilises Boeing's two Athens-based field representatives, and has set up a rotable spares lease programme with the manufacturer at its Thessalonika base.

Olympic has also suffered the BR715's gearbox problems. "We found the initiation of a crack early on during a scheduled boroscope inspection," says Demenagas. The airline has since installed modified gearboxes with R-R's assistance, and awaits the outcome of investigations into the latest failure.

Of more concern is the airworthiness directive requiring the replacement of high pressure turbine disks by 5,100 cycles with a new disk cleared to 15,000 cycles. This will require engines to be sent to R-R Canada for repair. Demenagas is pushing R-R to have its engines repaired in Germany to speed up the process. The airline is negotiating the acquisition of a spare engine which it hopes to have in time to start sending engines for modification in 8-10 months. Otherwise Olympic faces a charge of $3,000 per day for R-R to provide support.

Demenagas says that the engine's overall performance has been satisfactory, and is pleased that fuel consumption turned out to be some 5% better than predicted.

While Olympic has not suffered the problems other operators such as Impulse have with the 717's Honeywell avionics, it says that supply of spares from the US company was a problem initially. There is still room for improvement, says Demenagas: "For example, the turnaround of the air cycle machines could be faster."

Despite the 717's success and the new hub strategy, Olympic Aviation is unable to firm up plans to expand the fleet further until the privatisation of its parent company is under way. The airline sees a need for at least two more 717s in the short term to allow it to boost frequencies, and more orders could follow depending on the Olympic group's post-privatisation strategy.

Source: Flight International