Boeing 747-8F et I

Boeing Completes 747-8 Freighter Taxi Tests



EVERETT, Wash., Feb. 6 /PRNewswire-FirstCall/ -- Boeing (NYSE: BA) completed taxi tests on the first 747-8 Freighter today. With Chief Pilot Mark Feuerstein at the controls, the airplane reached a top seed of approximately 90 knots (103.5 mph, 166.6 kph).
"The airplane performed well," said Mo Yahyavi, 747 program vice president and general manager, Boeing Commercial Airplanes. "Based on early indications, the airplane is ready to fly."
This was the last functional test planned before first flight. The first flight of the 747-8 Freighter is scheduled for Monday, Feb. 8.

Boeing 747-8 "met or exceeded" expectations in first flight



Boeing's first 747-8 Freighter flew great and flew like a 747 in its first trip Monday, according to its pilots.

"It's a big day for a big airplane," 747 Chief Pilot Mark Feuerstein said in a post-flight news conference. "We were able to accomplish everything on the flight plan, every single test condition, and every single test condition went very well."

The pilots did tests touching all of the airplane's systems, said 747 senior test pilot Tom Imrich, who was first officer on the flight. "They met or exceeded all of our expectations."

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The pilots tested the basic handling qualities of the aircraft, checking all of the configurations at various speeds and cycling the landing gear several times, and ran into few issues, Feuerstein said. "We only had four systems-related squawks, none of which would prevent the airplane from flying again right now."

The airplane, as expected, kept it simple in the first flight, reaching a top speed of about 230 knots and an altitude of about 17,000 feet, he said. "Probably the second or third flight we'll probably start opening up the envelope and go quite a bit faster."

Feuerstein acknowledged the front landing gear bounced a bit on the landing.

"It might have been a timing issue on my part, quite frankly," he said. "I was pretty excited to land."

The aircraft now will go into a previously planned layup to ensure it's ready for high-rate test flights and should fly again in two to three weeks, Feuerstein said.

Jim Albaugh, president and chief executive officer of Boeing Commercial Airplanes, said getting the 747-8 through first flight is just one milestone.

"It does reduce the risk, but there is a lot ahead of us in terms of the flight-test program," he said.

One noticeable aspect of the airplane was its lower fuel use than existing 747s, Imrich said. The 747-8 is more efficient thanks to new wings and engines, and also has upgrades to the flight deck, flight management computer and flight controls, in addition to being more than 18 feet longer and able to carry 24 percent more cargo than the 747-400.

Despite these changes, Boeing aimed to make the 747-8 fly like earlier 747s, so pilots don't need new training. The company accomplished that, Feuerstein said.

"Any 747 crew in the world could have flown the flight that Tom and I just did," he said. "Two things haven't changed: It still looks like a 747 and it still flies like a 747 and, quite frankly, it just doesn't get any better than that."

Noting all the changes, 747 program General Manager Mo Yahyavi said: "It is pretty close to a new aircraft, but it's still a 747."

Boeing has 108 orders for the 747-8: 76 for the freighter and 32 for the 747-8 Intercontinental passenger version.

The airplane will sell well, Yahyavi predicted. "We foresee and believe that this airplane is going to be really successful in the market."

Albaugh also gave a rosy assessment of the market for the 747-8 Freighter.

"When the market comes back this is going to be the freighter that people are going to have to have," he said. "We've had a history of making a pretty good profit on our programs."

Boeing has completed initial airworthiness testing on the 747-8 Freighter, clearing the way for engineers to accompany pilots on flights and for the remaining two flight-test 747-8 Freighters to start flying, the company announced Thursday.
"This is a critical milestone in our test and certification plan," Andy Hammer, test program manager for the 747-8, said in a news release. "With the addition of the other two airplanes in the near future, the test program will ramp up significantly. We will expand the flight envelope and demonstrate the airplane's capabilities."
Since the first flight in early February, the 747-8 has flown 13 times, for 33 hours, with five different pilot. It has reached an altitude of 30,000 feet and a speed of Mach .65, and conducted initial stall tests, other dynamic maneuvers and an extensive checkout of the airplane's systems, Boeing said.
"The airplane is performing as expected in the initial stages of flight test," Mo Yahyavi, vice president and general manager of the 747 program, said in the news release. "That's a tribute to the men and women who helped design and build this airplane."
In coming weeks, the jet will to fly above 43,000 feet and Mach .97. The test program calls for around 3,700 hours of flying, with first delivery set for the fourth quarter of this year.
Boeing has 108 orders for the 747-8 -- 76 for the freighter and the rest for the 747-9 Intercontinental passenger version

Third Boeing 747-8 Freighter Joins Flight Test

EVERETT, Wash., March 18 /PRNewswire-FirstCall/ -- The third Boeing (NYSE: BA) 747-8 Freighter, RC 521, successfully completed its first flight on March 17. It is the final test airplane scheduled to participate in the flight-test program for the 747-8 Freighter.

Piloted by Captains Paul Stemer and Keith Otsuka, with Ralph Chaffin serving as systems operator, RC 521 took off from Paine Field in Everett, Wash., completed a two-and-a-half-hour flight and landed at Boeing Field in Seattle. The airplane reached an altitude of 30,000 feet (9,144 m) and an airspeed of 245 knots, or about 282 miles (454 km) per hour. It took off at 3:27 p.m. PDT and landed at 5:58 p.m.

RC 521 has several tests scheduled in the test program, including fuel-mileage testing. The 747-8 Freighter flight-test program calls for all three airplanes to perform approximately 3,700 hours of testing both on the ground and in the air. The first 747-8 Freighter delivery is planned for the fourth quarter of this year.

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Boeing is investigating an unexpected buffet in the inboard flaps of the 747-8F, a design issue that may prompt a costly redesign and put significant pressure on the flight test schedule.

The buffet was first discovered following the first flight of the 747-8F on February 8th, when the aircraft extended its flaps to the maximum setting of 30 with the landing gear fully extended, say program sources.

Two independent program sources say landings with flaps set to 30 are being avoided until the issue is addressed.

Boeing confirmed the flaps 30 buffet, saying: "It is a discovery we are addressing. We expect to have discoveries during the tests and we then address them in due course. This is the nature of testing. It is the fundamental reason why we conduct a thorough flight-test program. You find issues and resolve them."

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The buffet, which has been described as "very apparent", has been traced to disruptive air flow coming off of the outboard landing gear doors.

Boeing ruled out a problem unique to RC501, the first 747-8F, as the same flap buffet was duplicated on RC522's March 15th first flight.

The second 747-8F test aircraft, RC521- the third to fly - made its maiden flight on March 17th.

The flaps on the 747-8F are one of the major aerodynamic changes incorporated into the latest version of Boeing's jumbo jet, with the outboard flaps single-slotted and inboard double-slotted.

By comparison, says one program source, the 747-400's flaps were triple-slotted allowing turbulent air to pass through; however, the single and double-slotted flaps provide "a lot more surface to cause a turbulent layer to form".

Unexpected structural buffet on aircraft surfaces can be common during flight testing, though the solution may vary from vortex generators to redirect the airflow or even a complete re-design of the disruptive part.

During the 777's flight test program in 1994, Boeing found the 777 discovered the aircraft's nose landing gear doors buffeted wildly when opening and closing at speed, prompting the installation of metal baffles in the nose landing gear well to redirect the airflow.

Boeing has devoted one of the three 747-8F test aircraft to addressing the flap buffet.

On March 22nd Boeing began flying RC522 with the outboard landing gear doors removed to assess the impact at the flaps 30 setting. The early flight tests confirmed that the source of the buffet was disruptive air flow from the landing gear doors. On March 23rd, RC522 flew with the upper portion of the outboard gear door re-attached.

Boeing is considering several solutions to the problem. One option involves reducing the flap extension to from 30 to 27. However, decreasing the maximum flap setting could raise the landing speed of the 747-8.

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The airframer has ruled out installing vortex generators on the inboard flaps to redirect the airflow, program sources say. The over-wing emergency escape slides on the 747-8I passenger variant could tear on the vortex generators.

The final impact of the 747-8F flap buffet is yet unclear. Sources say that without a final low-speed configuration, the aircraft cannot conduct community noise evaluations.

While RC522 is assigned to resolve the flaps 30 buffet, RC501 conducted variable center of gravity stalls. RC521 remains in post-first flight layup at Boeing Field.

Boeing is targeting the fourth quarter for certification and first delivery of the 747-8F to Luxembourg-based Cargolux, following a 1,600h flight test period and 2,100h of ground testing.

As Boeing prepares to begin the 747-8's flutter trials, it has inspected the test fleet for defective machined stringers that were found to be prone to cracking under certain loads. Meanwhile, the airframer is evaluating whether to bolster the flight-test effort through the addition of a fourth aircraft.
The area of concern centers on the upper part of the 747-8F's fuselage known as the "bonnet". The stringers, which run longitudinally along the aircraft, were inspected for thickness of the flange, which as a result over-machining can crack causing damage to the aircraft's primary structure.
Boeing has confirmed the quality issue, which originated with a sub-tier supplier to Vought Aircraft Industries. Vought builds panels for the majority of the 747-8's fuselage and empennage.
While Boeing maintains that "all three flight-test airplanes have been inspected and cleared for flight," two programme sources suggest that while the aircraft remain airworthy, constraints on g loading could impact the operating envelope of the aircraft until the issue is fully resolved.
A Boeing spokesman says he is unaware of any restrictions on the aircraft, but adds that early flight tests are still working to expand the operating envelope of the fleet.


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The same sources add that flaps 30 buffet investigation would still continue as a final fix for the landing gear door induced vibration is being resolved.
Though another source close to the manufacturing of the aircraft says that inspections will continue on aircraft in production and could create a time consuming challenge to find, remove and replace the defective stringers.
With just over two months have passed since its 8 February first flight, Boeing's new jumbo is moving into the next phase of its 1,600h flight test campaign as aeroelastic flutter tests are set get underway.
Boeing says it is "making steady progress" on the flight test campaign and the aircraft are "performing as expected" is still targeting late 2010 for handover of the first 747-8F to Cargolux.
Following flutter testing, Boeing's three 747-8F flight test aircraft will transition to Palmdale, California for the remainder of the certification campaign that will encompass a total of 3,700h of testing, including 2,100h of ground testing.
While maintaining the pace of the programme, Boeing is considering "potential opportunities to gain efficiencies", including adding a fourth flight test aircraft.
Programme sources say that the second production aircraft (RC503), which is the fifth 747-8F off the line, is the likely candidate and would be used for engineering flight tests. This aircraft's role would be supplemental, as it lacks an instrumentation suite.
Boeing says that while no decision has been made about expanding the test fleet, the addition of a production aircraft for limited testing is a normal part of certification. It adds that the move is being studied as a potential opportunity to bolster the test programme.

Boeing develops fix for 747-8's flap buffet
Boeing has developed a solution to curtail the buffeting of the inboard flaps of the 747-8F at the maximum flap.

The final fix, which resulted in a modification of the outboard main landing gear doors, puts the lower panel of the door more in line with the upper panel, which was previously rigged at a 45° angle similar to preceding 747 variants. The modifications also include vortilons on the inboard flap as well as a bullnose design on the leading edge of the upper half of the outboard landing gear door.

The buffet was first experienced when the aircraft had its gear down and flaps extended to the 30 position. Pilots reported a "very apparent" vibration that was eventually traced to the outboard landing gear door. The issue was revealed following the first flight of the 747-8F in February, later validated by RC522, the second test aircraft to fly, as a design issue.

The 747-8F features an all new super critical wing design with the original triple slotted inboard trailing-edge flap system succeeded by a simpler double-slotted design.

As its all-new carbonfibre stablemate, the 787, progresses through its certification plan with relative swiftness, Boeing's 747-8F has faced more challenges through flight-testing that could put its year-end first delivery at risk, just as assembly work begins to accelerate on the passenger version of the venerable jumbo.
RC501, the first 747-8F, departed the same runway as its 747-100 predecessor on 8 February, just one day shy of the 41st anniversary of the venerable jumbo's maiden flight.

Since that date, Boeing has flown two more 747-8F test aircraft, RC521 and RC522, both destined for Nippon Cargo Airlines, which made their maiden flights on 17 and 14 March, respectively. The company plans to add a fourth flight-test aircraft to the fleet, RC503, the second production aircraft, to bolster the pace of flight hour accumulation.
While RC503 will undergo limited engineering tests, such as high-intensity radio frequency, water spray certification, wake vortex and high-altitude landing and take-off performance in La Paz, Bolivia, the aircraft will also be used for the collection of 1,600h of flight testing and 2,100h of ground testing data.
Jim Albaugh, Boeing Commercial Airplanes chief executive, cautioned at the company's 20 May annual investor conference that the first delivery to launch customer Cargolux will take place by the end of the year, but added: "There's risk to that. Every day we're trying to build contingency, every day we're trying to make sure that we have this airplane in a position where we can deliver it at the end of the year."

Following the first flight of the RC501, it was discovered that the outboard landing gear doors caused a "very apparent" buffet in the inboard flaps at the 30 detent, requiring significant attention to identify and fix the problem. While RC501 pushed through flutter testing, following its 11 March initial airworthiness clearance, RC522 was tasked with troubleshooting the buffet, which risked a costly redesign or an increased approach speed.
While a fix was devised and tested by May, the issue served as a time-consuming exercise that diverted the aircraft away from the certification plan, even as RC501 completed key tests.
The final fix, which resulted in modification of the outboard landing-gear doors, puts the lower panel door more in line with the upper panel, which was once rigged at a 45e_SDgr angle similar to the 747 variants that preceded it.
The modifications also include vortilons on the inboard flap as well as a bullnose design on the leading edge of the upper half of the outboard landing-gear door.
With concurrent flight-test programmes under way, Boeing shifted the 747-8F's base of operations from Boeing Field in Seattle to Palmdale, California, decoupling the certification effort and providing the jumbo freighter with its own dedicated resources.
RC521 and RC522 moved to Palmdale on 9 May and 19 April, respectively. RC521 was later transferred to Victorville, California on 23 May, where it has been undergoing nautical air miles testing to evaluate the fuel performance of the four General Electric GEnx-2B engines, its primary role in the flight-test campaign.
Early indications of the fuel economy of the new engine suggest better than expected performance, although final nautical air miles performance testing continued into late June, say programme sources. Results of the engine performance are expected in the fourth quarter.
Just before nautical air miles testing was set to begin on 31 May, RC521's right outboard - the number four - engine struck a parked airport tug during towing, inflicting serious surface damage to the nacelle requiring repairs before it returned to flying on 6 June.
The US Federal Aviation Administration granted an expanded type inspection authorisation to the 747-8F on 11 June, signalling the formal start to the aircraft's certification campaign.
While based in Palmdale, RC522's tests have consisted of evaluations of the aircraft interior that have included environmental control systems testing, lower lobe and main deck cargo compartment smoke testing, internal noise measurement and fire suppression systems.
RC522 also underwent hot weather testing at Phoenix-Mesa Gateway airport in Arizona from 21-26 June.
As the 747-8F looks to the road ahead, the aircraft faces challenges to an on-time delivery, including, say programme sources, addressing a middle envelope structural flutter issue requiring structural dampening or a revised control law, as well as oscillation issues in the inboard ailerons on the new wing caused in the presence of slow pilot inputs and very high hydraulic pressure forces.
Boeing has declined to comment on these issues, saying only: "We expect to have discoveries during the tests and we then address them in due course. This is the nature of testing. It is the fundamental reason why we conduct a thorough flight-test programme."


TAKING SHAPE
As the 747-8F pushes through flight-testing, inside the Everett factory Boeing is progressing with early assembly of its first 747-8I, the 467-passenger version of the jumbo.
Mohammed "Mo" Yahyavi, vice-president and general manager of the 747 programme, aims to have the development of the 747-8I progress smoother than its freighter sibling that is now in flight-testing.
To avoid the issues encountered on the 747-8F, Yahyavi transformed the process for how the engineering drawings are released. The technique, called non-recurring product development, is "nothing special in how you release the drawing". Yahyavi says "the processes are well disciplined. That takes you from the initial definition of the drawing to the final release, step by step. So you know exactly how the drawing is informed and if there are any issues in between these tasks, you would know it right away."
He adds: "You don't fall behind and have a trickle effect on the following drawings, and then the following drawings," which was an issue that delayed the engineering development of the 747-8F for nearly a year as design changes stacked up.
As of 21 June, Yahyavi says the 747-8I airframe engineering team has achieved 100% on-time design release for the previous 76 weeks using this technique, which was honed on the P-8A Poseidon, a programme he left to take the reins of the 747 in February 2009.
Additionally, Yahyavi's engineering team completed 100% design release on the 747-8I in the third week of June, a total of about 10,600 drawings for the new aircraft. Yahyavi says the new technique has been so successful it is being expanded to new development programmes.
Assembly for the new airliner, 5.6m (18ft) longer than the 747-400, began with the arrival of the Section 41 forward fuselage and cockpit from Spirit AeroSystems in Wichita, Kansas.
The 9.6m panels for RC001 that make up the nose and forward upper cabin and flightdeck were loaded into the assembly tool on 14 June, marking the first steps toward assembling the first 747-8I.
Yahyavi says the sections came in with virtually no travelled work and part shortages, and very minimal quality issues, a "major, major improvement" over the same Section 41 for the first 747-8F.
As of late June, RC001's left wing was in major assembly, while the right was in component build-up.
The first 747-8I, the 1,434th 747 to be built, will be one of two flight-test aircraft used in the certification campaign expected to kick off in early 2011, following a January roll-out. The second aircraft, line number 1,435, will eventually be delivered to Lufthansa, which has 20 on order.
First delivery of the 1,436th 747, the first production 747-8I, for a VIP customer believed to be a Middle East head of state, will be handed over to a completion centre for outfitting in the fourth quarter of 2011. Lufthansa expects its first 747-8I in early 2012.

FARNBOROUGH -- Since its first flight in February, Boeing's 747-8F flight test program has
completed roughly a third of its 1600h flight test campaign, though steady momentum has been elusive, as the new jumbo freighter has encountered one time consuming technical issue after another.

The sum of three main issues, including two more recent ones, have eaten Boeing's remaining margin, causing Boeing Commercial Airplanes president and CEO, Jim Albaugh, to caution that "The entry into service could slip into 2011."

With the landing gear door flap vibration issue now resolved, flight test challenges have given way to troubleshooting two primary issues.

The first centers on the aircraft's inboard ailerons and the power control unit that drives them. Boeing found that when a pilot makes a slow input on the jumbo jet's controls the high pressures in the hydraulic system cause an oscillation, requiring a fix in the actuator, according to two 747-8 program sources.

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The second, the freighter was found to encounter a structural flutter at mid-weight near cruise speed, requiring engineers to dampen out the aeroelastic vibration. Options for resolution include adding structure to the wing or potentially developing a new control law to avoid the condition.

RC501, the lead flight test aircraft based at Boeing Field in Seattle, has for the last month and a half has been dedicated to trouble-shooting both issues. Programme sources say the company aims to complete resolution on the flutter issue by the close of the month.

Boeing declined to address the specific issues encountered by the program, though the company continues to caution that while first delivery to Cargolux remains "at risk", certification is remains targeted for year end, adding:

The 747-8 Freighter flight test development program is a dynamic process of performance demonstration, validation and issue identification and resolution. To date, we've flown approximately 550 hours and completed substantial airworthiness, aerodynamic performance and systems testing. Over the course of testing, technical issues are discovered and resolved. As we advance toward completion of flight testing, fewer and fewer discoveries are expected. As we have previously demonstrated, when an issue arises, we address it immediately.

With five months to go in that goal, Boeing's remaining flight test margin is virtually gone, with the company's Flight Operations, Test & Validation organization looking for ways to find - or create - contingency where available. Boeing has already opted to grow its flight test fleet from three to four, with the addition of RC503, which may fly before the week is out, heading immediately into high intensity radiated field (HIRF) testing in Arizona.

Compared to its composite stablemate the 787, which has progressed more swiftly through its flight test campaign, 747-8F has struggled to find its footing along side the company's flagship program. While still technically a derivative aircraft of the 747 family, the aircraft's all-new fly-by-wire wing, engines and avionics, make it a significantly different aircraft from the variants that preceded it.