Sunday, October 9, 2011

Fait Accompli !

ZA 001 flying over the Oregon coast during flight testing. The clean lines of the 787 are evident in the photo, as is the distinct curve of the composite wing, typical at light weights without a heavy fuel load in the wing. Photo credit Boeing

It’s done. Complete. Finished and signed off. The flight testing of the Boeing 787 has been finished after a three-year marathon. On 26th September the first 787 was handed over to launch customer All Nippon Airways at the Boeing facility in Seattle. It was flown to Japan on the following day.

It wasn’t supposed to be like this. Original Boeing plans claimed an orderly ramp-up of the 787 to first flight, an eyebrow-raising 8-month of flight testing effort to certification involving 5 aircraft, then a switch to the 747-8… Very neat. Of course, the 747-8 was only a development of the 747-400, so that should have been a piece of cake….(more at a later date on this)

(I’ve done similar flight test planning so I know that life/reality and engineering problems will inevitably play havoc with any schedule..the best laid plans of mice and men etc.)

It was an ambitious plan. For a new composite airliner, it was very optimistic.
Things started unraveling early, with fuselage barrel sections for the first aircraft delivered with temporary fasteners. World-wide suppliers turned out to have world-wide problems.
Then a weakness in the 787 wing-to-body junction caused a massive delay, due to the need to redesign and then fix the problem on the first four test aircraft.

(The first four 787s cannot be sold to the airlines as their structures are not certifiable.)

Boeing 001 eventually was cleared for flight and flew in December 2009……

According to Chuck Killberg, Chief Pilot and Director of Flight Operations for Boeing Test and Evaluation it took 210 pilots and 3000+ engineers in the Test and Evaluation group to complete the testing. It basically took six flight test aircraft working full time, and another three production aircraft which were pressed into service in the later stages of the program.

The flight testing took 1782 flights and a whopping 5049 flight hours. It included the spectacular crosswind testing at Keflavik, the tail-scraping minimum unstick speed testing (at Edwards Air Force Base) and rejected takeoffs ending up with glowing brakes. You’ve probably seen it on You-tube.

Less spectacular was the steady progression of flutter flying, which required hour after hour of painstaking testing to higher and higher speed on the first aircraft (while the rest of the fleet was restricted to a pedestrian pace as they flew about the country) The day they achieved flutter clearance was a big milestone as all the aircraft could then fly at normal cruise speeds.(This chopped an hour off the cross-country time from Seattle to Victorville)

Boeing flight testing of the 787 was carried out at Victorville in Southern California, to take advantage of the good weather, in addition to Boeing Field in Seattle and Moses Lake in Washington State. One of the prototypes is seen here at Victorville in 2010 when the flight test program was in full swing. Photo credit David Brown

Boeing 001 spent weeks at Edwards doing takeoff performance testing, mainly single-engine testing, starting in the early morning.

What is probably just as impressive is the high-altitude takeoff and landing performance testing, done at El Alto International Airport at La Paz, Bolivia by ZA 005. This airport is at a mind-blowing altitude of 13,325 feet, and the air is so thin that hotel guests are provided oxygen in their rooms at night to help them to get to sleep.

The whole program stumbled when an electrical fire on ZA 002 in October 2010 caused a halt to all flying, a big investigation and a redesign of an electrical panel (not untypical, but very public and time-consuming) with a further delay while all the aircraft were upgraded.

Among the last tests was the proving of the ETOPS performance, which involved climbing to 37,000 feet, shutting one engine down and cruising for 345 minutes on the remaining engine. Not spectacular, but one of the boxes to be checked off to certify a safe, cheap and efficient aircraft. Similarly the trials to prove cruise air nautical miles per gallon(anmpg). The 787 is claimed to be 20% better than existing airliners, so it has to be proven. I would often see one of the 787s climbing out of Victorville and heading out over the Pacific on its testing for anmpg. Not exciting or glamorous flying, but absolutely necessary to prove performance to the customer.

787 design.

The 787 is 50% composite with one-piece fuselage barrel sections which are simply bolted together, so making construction faster and simpler than conventional metal aircraft. The composite structure does not suffer from corrosion.

Passengers enjoy the benefit of larger windows (which can be dimmed with a switch) and lower cabin altitude. The air in the cabin will be cleaner and have higher humidity, so improving passenger comfort on long flights.

The wing is 7% more efficient. It is a clean wing with smaller flap and wing to body fairings, together with raked wingtips rather than the fashionable winglets. The ailerons are digitally controlled and will float upwards to offload gust loads. (in this way the structure can be made lighter, so saving 5000lbs. )

The last certification flight is complete, with the Boeing 787 seconds from touchdown in Seattle. Pilots can use the velocity vector symbol in the HUD to ensure they hit the precise touchdown point. Photo credit Boeing

The 787 cockpit is similar to that of the existing 777. In fact Boeing is offering a common 5-day course for the crew to qualify for the 777/787.

The Boing 787 Flight deck features five Multi-Function Displays and both pilot and co-pilot have head up displays directly in front of them. The cockpit layout is similar to the Boeing 777 and a common conversion course is provided for pilots new to the 777/787. Photo credit:Wikipedia

The cockpit is dominated by a total of 5 Multi-Function Displays with two Electronic Flight Bags (EFBs) as a step towards the ultimate paperless cockpit. Checklists are electronic. Conventional control columns and throttles enable the pilots to interface with the digital flight control and autothrottle systems.

Each pilot has a Head Up Display.directly in front of him. Long used by Miltary Aviation, the HUD is especially useful for approach, when its flight path vector enables precise tracking of the touchdown point all the way down to the ground.

Building on the TACS system (Thrust Asymmetry Compensation System) used for the 777, the 787 has an improved version (ITACS) which senses thrust asymmetry and moves the rudder to compensate for loss of an engine and achieve co-ordinated flight.

Engines are either the Trent or the GenX. Package A Trents gained certification on August 13, with Package B and the GenX coming later.

Noteworthy about the 787 engines is that there is no engine bleed. So engine performance is retained during takeoff. (Older aircraft suffer a takeoff performance penalty with some air bled off for the air conditioning .) As the 787 is largely electric, it has 6 generators, with two on each engine and another pair driven by the APU.

Passengers will notice the improved and spacious cabin layout.

Overhead bins have been redesigned and are larger and more convenient to use.

The 787 is QUIET. Engine nacelles incorporate low-noise chevrons to improve the acoustic performance. The 85db noise contour around the typical runway on takeoff for the 787 is significantly smaller than that produced by current jets.

The bottom line

In summary, the 787 has 20% lower fuel consumption together with 15-25% lower operating cost.
The 787-8 has 242 seats and already on the horizon is the 787-9 with 280 seats.
This will have longer range, to enable it to operate between more city pairs.

The 787-9 is two years away (flying in 2013) so in theory the flight test teams at Boeing have a chance to catch their breath. But with the Boing 747-8, KC-46 tanker and P-8I to complete flight testing, and the 787-9 flight test looming on the horizon, chance of a rest may be just a dream.

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