The Boeing 787: A Pilot's Dream?

 - December 29, 2017, 4:05 PM

When you first walk into the flight deck of the Boeing 787, there are a number of impressions that immediately set this aircraft apart from previous Boeing types. Most superficial, but immediately obvious to a 757 pilot such as myself, is the gray flight deck. It lends the cockpit a more modern appearance, compared with the brown of previous types.

Far more significant to the operation of the aircraft, however, are the head-up displays (HUDs) stowed flush with the overhead panel; five 15-inch multifunction displays (MFDs) dominating the instrument panel; two large tablet-size Class III electronic flight bags (EFBs) outboard of each pilot seat; and, positioned inboard of each pilot's knee, the cursor control devices (CCD) used to enter and modify data to various aircraft systems.

Two common core resources (CCR) cabinets lie hidden under the cockpit floor in the forward electronics equipment (EE) bay, further setting this aircraft apart from 20th century designs. Pilots interested in understanding this machine better can clamber up through the EE bay access hatch beneath the forward fuselage, bringing them face-to-face with the two CCRs. For those of a certain age, comparisons with Arthur C. Clark’s HAL9000 units of “2001 A Space Odyssey” fame, are hard to avoid. Close by are the four flight control electronic cabinets, which provide the pilot interface that determines how this aircraft is going to handle.

Once seated, a pilot with previous experience of other Boeing types will quickly see more of the familiar than the unfamiliar about this aircraft. The layout of the overhead panel will make any 757 pilot feel instantly at home with electrics, hydraulics, fuel, air conditioning and pressurization controls laid out from left to right. Situated in between the left and right forward instrument panels are the integrated standby flight display (ISFD), gear lever and autobrake selector. And a familiar control stand houses the speed brake lever, throttle quadrant and flap lever. The aft control stand contains three tuning control panels, integrated for all VHF, HF, satcom and cabin interphone functions in one unit. Weather radar and transponder controls are also provided for in these intuitive and user friendly boxes.

Few Touchscreen Controls´╗┐

Forward of the control stand, where you would look on previous types for the control display units (CDU) of the flight management computer (FMC), is one large MFD, which, like the other MFDs on the forward panel, is capable of displaying navigation displays (NDs), electronic checklists (ECLs), system synoptics or the interactive graphical CDUs. Being creatures of habit, most pilots would select the CDUs into these positions and this is where the 787 fun begins.

In this world of tablets and smartphones, the instinctive reaction is to press the gray line select keys on the screen of the CDU, assuming it to be a touch screen. But it isn’t, and most pilots learn to stop doing this after a few simulator sessions—although their fingerprints on the screen give them away.

On either side of the lower MFD are two multifunction keypads (MFK), one for each pilot, that contain an alphanumeric keypad, a rotary cursor control device (CCD) and a touchpad-controlled CCD. It is through these that all FMC data is entered and amended, and this does take a little getting used to. An ACARS request to operations will download the initial route to the FMC, and CDU “help” messages will instruct how to make this the active route. But thereafter, all alterations are made by typing data into the scratch pad at the base of the CDU, selecting the cursor to the appropriate screen, and either positioning it using the rotary selector or the touchpad, before entering it using the cursor select switch on the top of the rotary switch or at the side, mouselike, of the touch pad.

If the selection requires executing, this can be done either by positioning the cursor over the graphical execute light on the CDU or using the hard key on the MFK. Boeing provided several ways to do most tasks, and users discover through trial and error the way of operating they find easiest and quickest. With age, some touchpads can become either less responsive or wildly sensitive and can make for a frustrating day out. So on occasion, the rotary CCD can become the preferred method of entry as a work around.

Having programmed the FMC, the user turns attention outboard to the EFB and performance calculations. Now, the EFB is a touchscreen again, with hard line select keys around the outside of the unit, but the cursor can be used for better accuracy, especially if using the chart functions. The EFB will be familiar to B777 pilots as it is the same unit and FMC data is easily copied, ambient conditions entered and a takeoff performance calculation made. Be warned, the EFB is very slow. Patience is required, especially if you have selected all intersections and/or the runway is wet. It is not unusual to wait several minutes for speeds to be produced. Once the V speeds are calculated, they can be sent over to the FMC, which will populate the takeoff reference page and display all the relevant speeds on the PFDs. The V2 will need to be entered manually onto the mode control panel (MCP).

We are getting very close to getting under way, but one thing we need to look at before we fly is the HUD. To unstow the HUD glass combiner unit, the locking lever must be pushed to release and the HUD moved downward to click into place in front of the pilots’ seated positions. I say, into place but, you will have adjusted your seat, using the electric controls, to a position that feels familiar from experience in previous types.

But this will not allow you to see all the information the HUD can provide. To see all the required data projected from the overhead projector onto the glass combiner necessitates a specific head position. The seat needs to be adjusted until the flight mode annunciations at the top of the HUD and the selected heading at the bottom left of the HUD are in view. This will almost certainly leave you with a seating position that feels too high and too far forward. On other types without a HUD, some pilots will sit high, some low. But on the 787, there is only one position for the head, and we just have to get used to it.

The electronic checklist must be reset before every flight, and once completed, in normal operations it is reasonably intuitive. The ECL senses control positions. If they are in agreement, the item on the checklist appears in green. Other non-sensed items need to be selected using the cursor. For example, the single item “Before takeoff checks” read, “Flaps” and if the flap setting selected is in agreement with the takeoff calculation in the EFB, then it appears in green and the pilot monitoring (PM) can announce, “Before takeoff checklist complete”.

Time To Fly

It is probably fair to say that Boeing has gone out of its way to not reinvent the wheel when it comes to the handling of the 787. First evidence of this is that the pilots still get a conventional yoke, although type rating commonality with the 777 almost certainly has a lot to do with this decision. The only unfamiliar switch on the yoke is the de-clutter mode for the HUD, next to the autopilot disconnect switch. It selects a mode useful for crosswinds and autolands and is useful early in training to become familiar with these switches to avoid inadvertent autopilot disconnect.

The yoke contains two conventional-looking stabilizer trim switches, but the philosophy of operating these switches is worth understanding before we fly. On the ground, moving both switches directly moves the stabilizer to the required setting for takeoff, as indicated on the engine indicating and crew alerting system (EICAS). In the air, in the normal flight control system mode, the trim switches select the trim reference speed into the primary flight computers.

So, let’s think how this affects the handling practically during a takeoff. Using the HUD to pitch the aircraft symbol up to the initial climb reference line calculated from performance data, we should arrive at a speed in the region of V2+15 knots after a pitch rate of approximately 2.5 degrees per second. If we select the trim switches, this speed is selected into the PFCs, and the elevators are moved to ensure that if you release force from the yoke, the speed will be maintained. The stabilizer will now move automatically to streamline the elevators.

When we reach our acceleration altitude, if we lower the nose to accelerate and do not move the trim switches, we will feel a progressive nose-up out-of-trim force as we move away from our previously selected trim speed. In theory, one could accelerate the aircraft to flaps-up speed—around 230 knots—holding this nose up force, which would by now be quite considerable. Then one press of the trim switches on the yoke would set the trim speed, and we wait for the elevator to reposition and all force to be removed.

In practice, one press of the trim switch for every 10-knot increase in speed will maintain the aircraft in trim as we accelerate. In normal mode, this works for all configuration changes, whether we are deploying flaps, speedbrakes or gear--or if we’re  adding or reducing thrust. As long as the speed remains constant, then the aircraft will remain in trim.

This system is relatively transparent for most of the flight regime but is very apparent in certain configurations. Those familiar with previous Boeing twins will be used to reducing pitch attitude when selecting flaps beyond five degrees to prevent a climb, for example approaching the glideslope. On the 787, flying with reference to the flight path vector on the HUD, on selecting flaps 20, no pitch input is required. But you will notice the pitch attitude reduce to one degree, from around five degrees, to maintain the current trimmed speed. When you first see this, it can be a little disconcerting, but you quickly get used to it.

One Engine Out

Single-engine handling also benefits from the advances in the flight control system. The most demanding maneuver most pilots are tested on in the simulator today is the “engine failure on takeoff” scenario, as it has been since twin-engine aircraft became commonplace. During the takeoff roll at speeds above 60 knots, the 787 flight controls will input the majority of rudder deflection required to keep the aircraft on the centerline. And the back-driven rudder will move to enable both pilots to recognize the failure. The pilot is still required to put in additional rudder, and this is essential to effecting a successful maneuver because the 787 wing is so efficient.

If any yaw is allowed to develop during takeoff, the aircraft will roll toward the direction of yaw and the heading will change significantly. That said, with the correct amount of rudder, the engine-failure characteristics are benign. Once the aircraft is off the ground, the pilot has to remember how the flight controls will look with all the yaw caused by the engine-out. Also, pressure on the pedals must be removed to allow the rudder to move automatically. The rest of the approach is flown almost identically to the twin-engine approach, with no manual rudder trim being required. 

Envelope protection is another huge advantage of digital fly-by-wire controls, especially in reducing the potential for upsets, currently the number one threat in commercial aviation. The 787 provides bank-angle, overspeed and stall protection in normal mode, all of which pilots find intuitive. Rather than restricting the flight envelope, the 787 will modify control inputs to assist the pilot in avoiding excursions from the norm, restricting the ability to trim into high- or low-speed corners of the envelope. In the case of excessive roll, 35 degrees or more, it produces a roll force toward wings-level that can be overridden, if so desired.

So, in conclusion, is the 787 a pilot’s dream?

In its primary role of transoceanic, long-haul flying, the answer is most certainly yes. Data transfer within the aircraft and to external agencies is effortless, and the cockpit environment is pleasant and quiet. In the pattern, the 787 is a sophisticated aircraft, but one that flies like most conventional aircraft before it.

It has the unarguable safety benefit of envelope protection that still leaves complete control in the hands of the crew. It is relatively easy to hand-fly, as most of the undesirable aerodynamic traits associated with low-slung engines have been virtually programmed out, but it is still quite obviously a digital airplane. Some pre-smartphone era pilots might still hanker for the days when computers played no part in the flight controls of their aircraft. But the end product is, without doubt, perfect for the 21st century. The 787 might not handle like every pilot’s definition of a dream, but it might be that the definition of a pilot’s dream has just changed for the better.   

Richard Ward has logged more than 17,000 hours in airplanes and helicopters and currently is a type rating examiner in the 787.