Comments about technological history, system fractures, and human resilience from James R. Chiles, the author of Inviting Disaster: Lessons from the Edge of Technology (HarperBusiness 2001; paperback 2002) and The God Machine: From Boomerangs to Black Hawks, the Story of the Helicopter (Random House, 2007, paperback 2008)

Monday, November 22, 2010

Helicopters and High-Rise Fires: McDonnell Douglas's "rescue angel"

Here's the second part of my post on helicopters at high-rise fires. This focuses on McDonnell-Douglas's flying rescue machine. The material is adapted from my book The God Machine on the social history of helicopters.

By 1976 it was clear that helicopters responding to high-rise fires like Andraus and Joelma were having problems with unruly crowds and smoke obscuring the roof. 

One solution, it seemed to fire chiefs at the time, was to keep the rescue helicopter high above, away from fires where pilots might lose their orientation, or machines might sustain damage from heat or suffer loss of power. In 1976 the chiefs of two dozen American fire departments wrote to McDonnell Douglas Corporation and described the problem. 

The aerospace contractor came back with plans for the Suspended Maneuvering System and went on to build a prototype. The SMS was a supercharged, sixteen-passenger rescue basket designed to hang from a large helicopter at the end of a 500-foot-long steel cable. 

The SMS had a gasoline engine and adjustable air-thruster nozzles so the operator could move the basket from side to side at the end of that tether, allowing it some horizontal freedom of movement when alongside a tall structure or above a flooding river. It had a little catwalk that could be lowered to bridge the SMS and a window.

The SMS was working in prototype by 1978. Here's a link to a Pop Mechanics profile about how MD's "angel" did in the early tests. Despite their early enthusiasm, though, fire departments dropped all plans to buy them. The chief obstacle was not the rescue device itself, which worked well in tests, but the logistical demands it placed on a fire department compared to the rarity of its use. 

Any department that would be depending on the SMS would have to arrange for fast response by a big twin-engine helicopter comparable to the Sikorsky H-60 Black Hawk. That's because of the weight to be carried and the need for extremely high reliability whenever people are being hauled around at the end of a cable hooked to the belly of a helicopter. (A hair-raising subject, and one for a later post.)

Also weighing against deployment of the SMS was a scarcity of high-rise fires after the early 1980s. The frequency plummeted after big cities began requiring sprinkler systems in skyscrapers, a move spurred by the disastrous conflagrations of the Seventies. 

Sprinklers and other fire-minded measures worked so well in stopping fires before they caught that if a fire chief had authorized an SMS unit in 1980 he could have worked another three decades and retired without seeing the SMS squad go into action, even once, at a high rise fire in his city. 

Only one department, the Los Angeles Fire Department, actually readied the SMS for action. That deployment lasted less than a year. I talked to a firefighter who participated in the effort, and he said it performed much as advertised. Here's a link to an image of the SMS as displayed in the LAFD's fire museum.

Would an SMS have been of any use at the World Trade Center that morning of September 11? I believe so ... After all, the SMS was designed specifically for getting people off of high-rises on fire -- including through the windows where the roof was untenable or unreachable. Still and all, the very short time span available would have been a problem. Everything about the mobilization would have had to operate without delay or error, with all forces from the Air National Guard to the NYPD's Aviation Unit to the FDNY acting as one.

Emerging reports about reckless practices behind the recent Shanghai high-rise apartment fire (death toll now up to 58) indicate that other high-rises there are at risk until if and when safety practices are cleaned up. So that city's FD might want to look into setting up an SMS unit; for one thing, helicopters are more reliable now and have better auto-hovering controls. It could be a lot better than nothing!

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