Today's airline companies have a better chance of staying in business and
making money if the cost of maintaining their fleets of airplanes is kept low and daily
dispatch reliability from the airport gate remains high. And both of these two
keys to financial success depend a lot on how the airplanes are designed in the
first place.
All businesses have direct operating costs. In the case of airlines, they include
what carriers pay for owning their airplanes, fueling them, employing flight and
cabin crews, and other necessary expenditures to continue carrying passengers.
A big part of these costs go for maintenance. In fact, the world's airlines spend
more than $40 billion annually on their airplanes, with the typical airline spending
as much as 20 percent of its costs for keeping airplanes ready to depart on time.
"Maintenance costs are those needed to restore or maintain an airplane's systems,
components and structures in an airworthy condition," said Jim Phillips, vice
president of the Boeing 717 jetliner program, which is located at the company's
final assembly plant in Long Beach, Calif.
In developing the 717, now in regular passenger service around the world, Phillips
said the company focused on the relationship between maintenance and
reliability. "Our design team had several goals, such as reducing the number of parts, minimizing
downtime and improving access for mechanics, he said."
Steps Taken During Design
To make sure it stayed focused, Phillips said, the team carried out certain steps
during design. First, they reviewed dispatch records for Douglas-designed twinjets,
looking closely at the MD-80 fleet of more than 1,100 airplanes in service. Using
this data, the team worked to boost 717 reliability to 99.1 percent and cut
maintenance cost by 20 percent.
Next, the team set up airline advisory groups to improve the flight deck, cabin interior
and systems. Many proposals reduced maintenance and increased reliability. Two of the
groups also worked with Rolls-Royce to improve the engine.
Third, a chief mechanic was assigned to the 717-design team as an airline
advocate to ensure that all decisions considered real-world conditions.
Focus on Targets Paid Off
The fourth step looked at the causes of non-routine maintenance on previous twinjets.
For the MD-80, the team found that delays at the airport gate were attributed to nearly
1,700 airplane components. Of these, only about 100 caused half of all departure delays,
making improvement of these components a high priority.
At the same time, the team successfully retained designs on other twinjets, including the
airplane's simple and reliable primary flight controls.
Systems throughout the 717 were redesigned to simplify components and to speed up maintenance.
For example, 717 environmental controls now have 27 percent fewer line replaceable units than
the DC-9 and MD-80. The electrical system was streamlined from 60 to only nine major components, eliminating 150 wires, and the
landing gear’s steel brakes were attached with pins instead of fasteners, cutting installation time by 60 percent.
Rolls-Royce produced a 717 powerplant that is relatively easy to maintain. The engine resists
damage from foreign objects; it allows mechanics to stand on lowered cowlings to perform work
using standard hand tools; and the lengthy interval between replacement of life-limited parts lowers material costs.
Supporting the Customer
Boeing Field Service representatives help airlines introduce their new 717s into service.
They also advise carriers on how to maintain and operate the airplane, use technical
publications, purchase parts and receive training. And they work with customers on
technical problems, design changes, warranties and incidents.
The business-to-business web portal MyBoeingFleet.com offers operators access to Boeing
technical information and services. Airlines use the portal to store and retrieve data
from their maintenance, engineering and operations departments.
Operators of the 717 receive engineering, program and quality assurance support. They
also can get help in repairing, overhauling and exchanging airplane components.
The 717 Performs
So, how well is the 717 performing in daily revenue service?
"Our operators tell us the airplane is meeting and even exceeding expectations,"
Phillips said.
According to fleet dispatch statistics reported to Boeing, the 717 is beating the design
target of 99.1 percent for on-time departures. Several operators have achieved more than
99.5 percent. In fact, the 717 has achieved a monthly average of 99-plus percent dispatch reliability faster than any competing
airplane, demonstrating that it provides dependable operation for airlines and their
passengers.
The 717's excellent "out of the gate" reliability is even more impressive in light of
demanding short-haul service common to 717 operators. One customer, Hawaiian Airlines,
operates a fleet of 13 airplanes on an inter-island network of very
short-range routes with an average of 14 flights a day per aircraft.
"The 717's dispatch reliability in such challenging environments is no surprise,"
said Tom Croslin, chief project engineer, "because the airplane was specifically
designed for intensive, high frequency regional operations."
There's also good news on 717 maintenance, with data from operators showing
much lower costs compared with the DC-9. For instance, AirTran Airways reports
that it's doing better than Boeing expectations. Out-of-service time for its 717s is
80 percent less than for DC-9s. The airline's extensive maintenance inspections,
such as C-checks, are averaging three days for the 717 and 21 days for the DC-9.
The U.S. Federal Aviation Administration has extended AirTran's interval
maintenance checks, based on its good in-service experience with the 717. The
time between C-checks increased to 4,500 hours or 18 months.
AirTran reports that the 717 saves labor hours compared with the DC-9. It also
finds that C-check costs for the 717 are 10 percent of those for the DC-9.
Hawaiian has found that the 717 allows it to lower costs by taking advantage of
the airplane's digital technology to know how each system and component is
performing to anticipate problems before they happen.
Other 717 operators, such as Aerolineas Baleares, Bangkok Airways, Olympic
Aviation, and QantasLink, also have reported similar cost savings and reliability
benefits, thereby increasing their financial success in the 100-seat market.
The newest 717 customer, Midwest Express Airlines, purchased the airplane
because it "uses advanced technology, resulting in improved dispatch reliability
and significantly lower operating costs than our current fleet in terms of fuel
efficiency and maintenance," said Timothy Hoeksema, chairman and chief
executive officer. |
