Boeing is facing a challenge on three fronts in 2011 as it aims to complete certification on three major programmes simultaneously - the 747-8I, 747-8F and the 787 - the first time in its history it has attempted such a demanding target.

Delays on all three projects have caused the programmes to bunch into the same calendar year, but Boeing remains confident that it can hit its deadline for each aircraft.

The 747-8I is the next programme to get under way. This will require a flight-test campaign of about 600h using two aircraft. It will start in late March, with flight-test completion in the autumn, followed by year-end certification, says Elizabeth Lund, 747 vice-president and deputy programme manager.

The first 747-8I is scheduled for a late 2011 handover to a Boeing Business Jet completion centre.

Meanwhile, Boeing is aiming for mid-year certification of the 747-8F and a third-quarter completion of 787 flight tests. "The schedule is achievable, but aggressive," says Lund.

Boeing 747-8I
Cargolux 747-8F
 © Boeing
Will Boeing be able to cope with three simultaneous certification campaigns?

"If we have a major discovery it's always a risk in a development programme, but given what we know and the learnings we've taken from the Freighter and what we've put into this programme, we believe this is a schedule we can meet.

"Many of the tests we are doing on our freighter will also give us [certification] credit on the Intercontinental. We don't have to test everything from scratch," says Lund.

Tests already completed on the 747-8F, and not required on the -8I, include the flight loads survey, artificial ice shapes testing, wake vortex, water spray and community noise testing. Still left to be completed are extreme weather tests at high winds and high temperatures.

Boeing aims to leverage staff from across the company to assist in the flight-test effort, while hiring additional personnel "to ensure we have the critical skills necessary to execute on our test commitments".

With 747-8F and 787 flight-test programmes ramping down "the size of test teams required for those airplanes decreases and we are able to redeploy test personnel to the 747-8I airplanes", says Boeing.

Boeing already has five 747-8Fs in its test fleet, with up to four 747-8Is. This is in addition to seven 787 test aircraft, which could grow to as many as nine to support systems functionality and reliability testing.

RC001, a future Kuwaiti government aircraft, is the first of two dedicated 747-8I test aircraft. It is fully instrumented and designed for flutter clearance, flight controls, ride quality, and stability and control evaluations. RC021, which will eventually be delivered to launch customer Lufthansa, will handle much of the interior testing.

A non-instrumented third aircraft will perform electromagnetic interference testing, along with lighting and in-flight entertainment validations and a fourth aircraft may be used for additional interiors testing, or serve as a back-up if other test aircraft are in planned maintenance.

Having achieved power on in November 2010, followed by factory completion in January, Mark Feuerstein, chief 747 pilot, says of RC001: "I'm a expecting a finished, tight, ready airplane to fly."

Still outstanding for Boeing are the demonstration activities to show the Federal Aviation Administration how it intends to remedy the two biggest causes of its most recent schedule slip.

The first is the incorporation of the outboard aileron modal suppression (OAMS) system to dampen out a 2.4Hz vibration in the wing that resulted in a deflection of ±2.5cm (1in). OAMS activates automatically, by using the fly-by-wire outboard aileron to dampen the vibration.

Todd Zarfos, 747-8 vice-president of engineering, says: "We know it'll work and now we just have to go through the last aspects of certification associated with that.

"We had long conversations with the FAA on whether existing [Federal Aviation Regulations] covered what we were already doing. I'll just be frank, we thought they did, they characterised it as something 'new and novel' and that resulted in the need for a special condition," he says.

Further, an underperforming actuator was replaced due to inability to handle the 207bar (3,000lb/in) hydraulic system pressure, prompting its redesign.

Zarfos says the issues were traced to pressure spikes in the hydraulic lines and he adds that engineering teams are "now in the process of correlating" the actuator underperformance and the hydraulic pressures.

Zarfos says he is "very confident" in the technical solutions to show FAA compliance, but altering the installation as the result of a kinematic evaluation of the lateral movement and wing structural dynamics.

Once certification is complete at the end of the year, Lufthansa expects to take delivery of its first 747-8I - configured with 386 seats in three classes - in early 2012.

Source: Flight International