There is a common misconception in the commercial aviation industry that interiors don’t warrant the same level of scrutiny afforded other seemingly “sexier” or “important” parts of the aircraft, namely the airframe, engines and avionics.
When an engine malfunctions, for instance, the world knows in a nanosecond which company provided the engine, when it was last maintained and who handled the maintenance. Not so in the world of aircraft interiors.
“Everybody knows Boeing, Airbus, GE, Rolls Royce, and Pratt and Whitney. You see the aircraft, and who the engine manufacturer is. You can look at your safety brochure [in the seat] and see what airframe it is. Nobody knows who made the seats. Nobody knows who made the IFE,” notes Joseph Fritz, VP of research and operations for global research firm Lucintel, which released an interiors market report in February. He adds: “From my perspective – and I’m more on the mechanical side – the industry doesn’t get as caught up in a wringer when you look at interiors.”
Perhaps if we are to learn anything from this week’s events – which saw the loosening of seats on certain American Airlines Boeing 757 aircraft – it is that everyone should “get caught up in a wringer”, and start paying far closer attention to interiors engineering, certification, maintenance and installation.
Christine Negroni, who writes for The New York Times, puts it plainly in her blog FLYING LESSONS. “Airplane seats, love ‘em or hate ‘em, they’re doing the heavy lifting when it comes to improving survivability in all the ways airplanes can get knocked around; aborted takeoffs, runway overruns, turbulence, even those plane-to-plane collisions made famous on YouTube. Seat safety relies on a three-legged-stool so to speak: the seat structure, the passenger restraints and the attachment to the aircraft.”
In the case of American, the carrier has cited improperly installed saddle clamps as the root cause of the seat failure. “We believe a contributing factor is with the seat tracking and locking mechanism, not with where the work was performed,” says American. Indeed the carrier has now grounded 48 757s for further inspections, and instructed mechanics “to pay particular attention to the seat lock plunger mechanism that secures the seat to the aircraft floor”. Mechanics have begun taking steps necessary to ensure that no seat can become dislodged from its track.
But how does something like this happen? A LOPA (layout of passenger accommodation) is an engineering diagram of the aircraft’s cabin interior that includes locations of passenger and flight attendant seats, emergency equipment, exits, lavatories, and galleys. An aircraft reconfiguration project usually involves the reorganization or change to the LOPA. This is more of an exact science than it sounds.
Measurements must be precise. Seat legs must be locked at the exact spot on a seat track where there is an indentation for it. If you try to force it somewhere else, you can torque the seats to all the right tolerances and they will still eventually go loose. See the diagram to the right. “When people start moving seats around and they don’t know what they’re doing, that’s essentially what happens,” says Kosta Gianakopoulos, who serves as technical director at design firm Point Innovation.
It is perhaps somewhat ironic that American’s seat problems occurred whilst the carrier was trying to improve the passenger experience. American is reconfiguring its 757s – removing a row of Weber-made coach seats – in order to add legroom to 20 rows of seats. That’s a point worth celebrating, but not without acknowledging the precise – and taxing work – that is seat installation.
As Negroni points out in her blog: “American’s 757 troubles began because a lot of thinking goes into where we put our seats – as well it should.”