Space The Final Frontier

From new structural airframe options that add or subtract fuselage plugs or doors, to the finely detailed sculpting of plastics and polymerscarve out extra centimetres and millimetres at the front, middle and back of cabins, space has never been at so high a premium.

With airframers, interiors suppliers and airline decisionmakers boldly going where no one has gone before, the passenger experience is changing, in ways that are more and less obvious.

Airframers are adapting aircraft for new configuration options

With new airframe costs and timescales requiring serious commitment, evolved aircraft like the Airbus A330neo and A320neo, and Boeing 737 MAX and 777X are a significant part of the next decadeplus of aviation. The derivative variants of the Boeing 787 and Airbus A350 will join them.

The widebodies are larger, offering a greater number of options to adjust interiors even without airframelevel decisions. Widebody aircraft designers have the quite literal luxury of figuring out whether to put a first class shower, full double-bed suite, bar area or comfortable seating lounge at the front of the A380 upper deck. Not so much in a narrowbody.

With cabin widths of between 3. 53m (on the 737 family) and 3. 70m (on the A320 family), and the front and back of the single cabin space relatively set, the number of options are relatively fewer.

As a result, much spacesaving innovation is driven at the narrowbody end of the market, often trickling upwards to widebodies after introduction on smaller aircraft.

Where widebody size differences and space economies are likely to be driven by the choice of aircraft – does this set of missions call for an A330 or a 777? – the current set of narrowbodies offered by Boeing and Airbus are similarly-sized aircraft with similar issues likely to be solved in similar ways.

More doors means more seats. . .

One such similarity is the approach to adding capacity or enabling new internal configurations through the use of exit doors. This isn’t an entirely new innovation – notably, the Boeing 757‑200 came in two configuration options, one with a fourth door aft of the wings in addition to the standard three full doors and two overwing exits, and a stretched 757-300 was developed to add passengers.

Currently, the Airbus A321 has eight full-sized doors, compared with its Boeing 737-900ER competitor’s three doors and two overwing exits. (Boeing added a pair of Type II exit doors to the earlier, less successful 737‑900 to increase capacity. ) At the Farnborough Airshow outside London this July, both Airbus and Boeing announced incremental changes to boost seating numbers from their current core narrowbody offerings, the A320 and 737-800.

The Boeing 737 MAX 8 will follow this trend and will be offered with a mid-exit door to make the most of the often-quoted 2. 24m extra length of the 737-8 fuselage over the A320.

Where the A320neo is planned to max out at 189 passengers, the 737 MAX 8 will reach 200 passengers, slotting in above the 175-passenger mark of the standard 737-8 and below the 192-220-passenger range of the 737-9. It is unlikely, however, that airlines will fill the 737-8 with 200 passengers, since that would be the capacity threshold requiring an extra flight attendant.

Rather, the aircraft will likely see a 199-passenger layout (in all likelihood, 200 seats with one unsold), making it so appealing to low-cost carriers that industry wags have taken to referring to it as the 737-8 MOL, after Ryanair’s firebrand CEO Michael O’Leary.

Airbus is also adding an extra exit option on its four-door A321neo, this time an additional overwing door that boosts capacity to 236 on the A321, up from the 220 limit on current models – as seen on Jetstar’s aircraft with their kneecrunchingly tight 28in (71cm) pitch.

As an example of how narrowbody innovations trickle up to widebodies, the Boeing 777-9X will also have an extra 737-900ER door in the space between doors 3 and 4 on currentgeneration 777-300ER aircraft.

…yet fewer seats can also mean fewer doors

At the other end of the capacity scale, Airbus has an alternate optionvon its A321 and A321neo aircraft that disables the exit door forward of the wing, which the airframer says “creates a seamless, undivided forward cabin allowing additional seats and even more flexibility in multi-class seat arrangements. ” In particular, Airbus is aiming for “longer-range markets where high comfort standards are needed in premium class. ” In essence, those are the markets targeted by the former UK airline bmi on 154-seat A321 aircraft now operated by its purchaser British Airways on medium-haul markets in the Middle East and Central Asia from London. These A321s offer eight rows of the Thompson Vantage full-flat product branded as the airline’s Club World long-haul business class, alternating between rows of two seats and one solo “throne” seat on both sides of the aircraft. The bmi/BA implementation was the first time the Thompson seats had been chosen for a narrowbody aircraft. Crucially, though, this configuration retains the exit door in row 7, ahead of the wing.

The concept has been developed by US airline jetBlue on its transcontinental Mint A321 aircraft, where the front cabin consists of the slightly larger Thompson Vantage XL product.

JetBlue’s implementation seats 16 in Mint, with three rows of fullyflat beds with two rows of personal solo suites, plus 41 passengers in extra-legroom Even More Space seats and 102 travellers in economy at a 33in (84cm) pitch.

The unusually low density tots up to 143 seats, below the 150-seat threshold that would require an extra flight attendant, and likely at a capacity and density that would allow evacuation through three sets of doors rather than four.

Removing the extra door for these lower density aircraft would likely allow a capacity increase of at least six economy seats or two-four premium seats – a definite bonus.

New cabin monuments offer landmark space savings

Combined with the big space savings at the airframe level are the spaces within the aircraft that aren’t revenue-driven: lavatories, galleys, bulkheads, partitions and overhead bins. Developments at this scale are often evolutionary rather than revolutionary, often involving carving out previously unused or underused space for cabin facilities.

When Boeing developed the 737‑900ER as an evolution from the poorly-selling 737-900 in the mid 2000s, it created an additional 66cm by replacing the previous dome-shaped aft pressure bulkhead with a flat bulkhead. In real terms, the space usually used for galley carts was increased by 75 per cent, from five carts to eight. (And, with space-saving lavatories and multipurpose galleys, that means that other facilities can be relocated to this area. ) In an apt example of the tradeoffs involved in aircraft design, the flat bulkhead is heavier than the domed version, adding to fuel burn yet also increasing passenger numbers.

Changes can also reduce the number of facilities offered.

Consider the case of the Boeing 777-200 operated by launchcustomer United Airlines. When the aircraft was launched in a threeclass configuration nearly two decades ago, 231 passengers shared six lavatories. On the three-class version that United currently flies on 14-hour flights between Australia and the US, the airline’s two published seat maps show four or five lavatories shared between 221 or 218 passengers.

Similarly, Qantas’s recent refitting of its Boeing 747-400 fleet from four-class to three-class has resulted in an increase of 20 passengers in economy, yet the number of economy lavatories has been reduced from six to four. That’s a significantly changed passenger-to-lavatory ratio of 68:1 rather than 43:1.

And even if lavatory numbers are not reduced, new, smaller facilities are being installed on factory-fresh aircraft and during cabin refits.

Wee lavatories are flush with success

Lavatories are a number one source for extra room in the cabin.

Delta is just one of the carriers creating more space via new B/E Aerospace-designed lavatories across several aircraft types.

To start with, B/E’s Spacewall designs scallop the sidewalls of the lavatories to allow the seats in front to recline. The new lavs also eliminate counter space, move narrower sinks closer to the door, and carve out space from underneath the sink unit. How much space do the new mini-loos save? On-debut airline Delta’s Boeing 737-900s, four more seats’ worth, taking capacity to 180 passengers, while B/E advertises that overall the Spacewall systems give up to six more seats per narrowbody.

With a two-three per cent capacity boost from simply changing lavatory supplier, it’s unsurprising that Boeing selected B/E as the exclusive manufacturer of modular lavatories for 737 Next-Generation aircraft from 2012 onwards, and for the upcoming 737 MAX. Airbus has gone in-house for a solution with its Space-Flex offering. Rather than occupying the entire aft end of an A320 Family aircraft with a full-width galley, a smaller galley (wide enough to accommodate three galley carts) is placed to starboard with two lavatories relocated to the centre and port sections. Two full-sized lavatories can thus be removed to enable an extra row of seating.

An additional benefit of the Space- Flex lavatory pair is that they are convertible from two regular-sized lavatories into one larger facility for passengers with reduced mobility, similar to the convertible lavatories on widebody aircraft.

Interior supplier Zodiac’s ISIS Aft Complex works on a similar principle, though without the convertible lavatory, but with additional lavatory plumbing efficiencies. Zodiac advertises that the design provides an additional 91cm of linear space for seating,which would translate to the usual three square feet footprint of a pair of standard lavatories at the rear of the cabin.

Galleys are logically evolving

Gone are the days when stewardesses – not yet flight attendants or cabin crew – prepared and carved chateaubriand in an expansive flying kitchen.

Despite the boutique flying chef offerings in international first class on airlines such as Etihad, the majority of inflight diners see pre-plated remove-and-serve food these days, if hot meals (or anything more than a bagged snack) is even offered.

When Qantas refitted its 747-400 fleet, it didn’t just cut the number of lavatories. The galley behind door 1 disappeared, and the galley behind door 3 moved from the centre section of the economy cabin to the starboard side, losing a curtained-off work area as well.

Narrowbody galleys are getting smaller, and the space allotted for cabin crew to work in them has shrunk. Many one-class narrowbody operators have removed the bulkhead on the port side of the aircraft, making seats 1A, 1B and 1C an exit row rather than bulkhead seat. The remaining forward galley in front of 1D, 1 E and 1F may be reduced from a twoside galley, with storage and work space aft of the door, to only seeing space allocated facing forwards.

Some airlines are opting out of having cabin crew serve drinks and snacks, at least partially.

JetBlue uses the half-a-row space between its premium Mint seats and the second set of doors on its transcontinental Airbus A321 aircraft to house a self-serve fridge and cabinet set that it calls the Marketplace. Economy passengers can help themselves to soft drinks and pre-packaged sweet and savoury snacks, reducing the workload oncabin crew, and even premium Mint passengers take a wander back to browse the refreshments on offer.

The space previously dedicated to galleys is even being repurposed.

LSG Sky Chefs and strategic partners Retail in Motion are offering a wireless entertainment solution where the server is encased in a galley oven insert (see Cabin Pressure, this issue).

Bulkheads are disappearing or going high-tech

As lavatories and galleys have been removed, repositioned and resculpted, the number of interior bulkheads throughout the aircraft has decreased, both in widebody and narrowbody aircraft. Australian airlines are becoming increasingly unusual in having bulkhead separators between business class and economy, though Virgin Australia’s magnetic “rope” instead of a curtain is closer to the global trend. Even airlines with partitions are starting to place seats closer to them.

Virgin Australia’s purple screens increase the feeling of space, and the cutout at foot level means more space. New safety improvements, too, are allowing closer positioning of front row seats. Head impact survivability requirements mean that passengers in bulkhead rows had to be placed far enough back for the standard 178cm crash test dummy to pivot at the hips and slam forwards without striking its head on the wall.

With new bulkhead airbags, however, head impact forces are reduced, just as in a car. In a trickledown from fully-flat business class seats, where certification has often required the use of airbags for over a decade, front row economy passengers are discovering that the bulkhead in front of them or their own seatbelts contain airbags.

Interiors supplier Zodiac has designed and is offering an airbag system integrated into the outside wall of galleys, and states that the system reduces the minimum distance from the bulkhead to the seats by 10cm. An added bonus for airlines: certification is only required once, when the galley unit is installed, rather than every time seats are changed.

Where bulkheads will remain, materials engineering advancements mean they are lighter, cheaper and more ergonomically designed. Race Completions is now offering a new welded plastic cabin partition that is a third lighter and a third less expensive than standard composite/ aluminium constructions. Literaturepockets can be recessed more easily into the molded plastic, while information placards and even safety cards can be printed onto the partition itself.

Integrated interiors packages offer engaging new options

Interiors suppliers are looking to become one-stop shops with integrated packages across the cabin.

Zodiac’s ISIS (Innovative Space Interior System) improves the passenger experience by boosting space with larger overhead bins and increased headroom, plusupdating the look of the cabin with a futuristic passenger service unit, flush joins between sections and a more modern aesthetic.

The manufacturer calls it a “complete reimagining” of the narrowbody interior, and that’s especially true for the A320 Family, which doesn’t offer a linefit equivalent to the Boeing Sky Interior update to bins, lighting and overall appearance. But even more meaningfully, ISIS slashes the number of parts required from 11 to four, simplifying and speeding up install and maintenance.

The 757 answer might resolve other next generation questions too

In the medium term before the next generation of narrowbody aircraft is developed to succeed the Boeing 737 MAX and A320neo, it’s likely that a replacement for the continuing missions of the Boeing 757, and particularly the 757-200, will need to be developed.

The 757 was first flown 32 years ago and last produced in 2004, yet there is still no direct replacement option for a decent number of key long and thin routes that demandat least a standard of fully-flat beds such as the B/E Aerospace Diamond seat.

Clever adaptation of an existing narrowbody could be the answer.

The A320 family’s higher ground clearance offers more engine options than the 737 family, making it more feasible that a combination of airframe and interior configurations could fit a replacement niche, even if not offering precisely the same number of seats.

Premium narrowbody services are prospering, showing airframers and interiors suppliers a market for efficient, lower-density aircraft dedicated to niche missions. And airlines want commonality with existing narrowbody fleets for maintenance reasons.

In addition to jetBlue’s 143- seat Mint A321s, American Airlines offers a three-and-a-half class service on 102-seat A321 aircraft with its transcontinental routes between New York and Los Angeles or San Francisco. Ten fully flat Zodiac Cirrus seats with direct aisle access provide a worldbeating domestic premium service in a 1-1 configuration, with 20 B/E Aerospace Diamond seats offering a fully flat seat in a 2-2 layout.

Spacious Main Cabin Extra and regular economy seats make up a surprisingly small proportion of the seats on board.

Those B/E Diamond seats are the same as international business class on Delta and United Boeing 757-200s that also operate on transcontinental routes, but are less premium-heavy. United’s aircraft have 169 seats, with Delta’s accommodating one fewer at 168.

Both airlines offer 16 seats in their business cabins, 108 in economy and 44 (Delta) or 45 (United) in extra-legroom Economy Comfort and Economy Plus.

It’s not a galaxy away from British Airways’ OpenSkiessubsidiary, which operates three Boeing 757-200s in high-premium configurations between Paris and New York JFK with just 112 or 114 passengers on board. As a result, OpenSkies can seal off one of the two overwing emergency exits on two of its three aircraft (which have three full-sized doors), and dispense with the overwing exits entirely on the other 757, which has a fourth door aft of the wing.

British Airways has retired the rest of its 757 fleet, and seems to be taking a wait-and-see approach to what’s next for OpenSkies. The natural answer would seem to be an aircraft offering commonality with its existing A318, A319, A320 and A321 fleet.

The trick to answering the longlived 757 question will be getting the right mix of passenger numbers, seat weights (especially in premium classes), lavatory and galley facilities, fuel burn efficiencies and range improvements to make the numbers work. It might require a slightly differently sized member of one of the narrowbody families to be optimised for the missions.

Using the A320 family as an example, with the flight attendant thresholds at 150 and 200, there is an opportunity for new variants between the A319 and A320, and between the A320 and and A321 – an A319. 5 and/or A320. 5, perhaps? Demand for that new variant to replace the 757, plus demand for narrowbodies increasingly optimised for crew and premium cabin efficiencies in other niches, could well combine to make a profitable aircraft subtype. Airbus might need to add as little as a metre or so to the A319, A320 or A321 – or Boeing to the 737 MAX 7, MAX 8 or MAX 9 – in order to make the optimisation work.

Even if the premium market doesn’t provide enough potential sales demand to make a return on investment, how long can Airbus allow the 737-8 MAX to have a ten-seat advantage at the LCCpitched end of the market? It is seemingly unlikely that an extra 10 seats can be carved out of the A320’s shorter fuselage, even at significantly reduced pitches of under 28in (71cm).

Regardless, the industry can expect a continuing journey of space-saving improvements both within and outside the aircraft, first focusing on the narrowbody market and then moving upwards towards widebody fleets.