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)

Saturday, February 13, 2016

Call to Adventure: When pax have to land the plane

If you've earned any kind of pilot's license, even the simplest single-engine-land license like me, you've probably thought about what you might do if called on to land a plane on which you're riding. It doesn't happen often (fortunately) but there are cases. Most common is when someone has to take the controls of a light plane after his or her spouse is out of action. But what about an airliner?

In December 2014 United Airlines passenger Mark Gongol heard such a call, because the aircraft commander had suffered a heart attack and was out of action. Gongol went forward and explained to the first officer that he had plenty of experience on Air Force jets. He helped her divert for a landing by operating the radios and acting as a backup. 

But what if both pilots are out of action, and there's no jet-rated pilot in coach or first class? Here's an interesting Quora answer, explaining how a steely-nerved passenger could land a late-model B737 in an emergency, with guidance from air traffic control:


While researching aerospace articles over the years, working with instructors in professional-quality training simulators, I've sampled a variety of jet-powered aircraft, and it was humbling!

One adventure was trying to land a simulated 737 at then-National Airport in Washington. I finally made it, but only after much assistance from a seasoned instructor. He handled the throttles so I could concentrate on the yoke, flaps, and rudder pedals, but it was still quite difficult; a critical skill turned out to be using the trim switches on the yoke. A later challenge was lining up a B-2 bomber with the refueling boom behind a KC-10 air tanker. (That simulator facility at Whiteman AFB had the strictest security precautions of any military installation I've visited, BTW.)

My takeaway: there's no substitute for small, well-timed inputs.  In the 737, the aircraft and its engines responded slowly to control changes, so it was easy to fall behind ... and fall to the ground. 

Friday, February 12, 2016

How to Park That Crane, Continued

Updating my post on the fatal crane mishap in Lower Manhattan last week ... 

The city has confirmed that the model was a Liebherr LR1300. Reporters at one of the city's press conferences asked if that meant the crane weighed 300 tons, or could lift that much; the answer is that in Liebherr's model numbers the "300" refers to the maximum hoist capacity under ideal conditions, meaning a short boom held at a high angle. It doesn't apply to the way the crane was rigged on Broadway and Worth Street, with a boom and a jib long enough to hoist HVAC gear to the top of a tall building. Here's the laydown zone (photo, FDNY):


Newsday did a good piece with interviews of crane experts on factors that investigators from the city's Department of Buildings will be checking ... things like, what operators should do to reduce the risk that a crane will overturn when lowering the boom and jib. And it may be that local wind-tunnel effects also played a role.

The proper procedure when weather-safing a long boom and jib is for the operator to run out the winch and set the hook block on the ground while the boom is still at a high angle. 

Doing that eliminates a big weight that would otherwise be hanging at the end of a very long arm as the operator lowers the structure to the street. That's a lot of leverage. 

Further, say the experts, the next smart practice is to lower the luffing jib (the smaller lattice structure at the end of the boom) into a vertical position, and only then lower the boom until the tip of the jib touches the street. The terminology makes more sense when looking at the diagram I did after the crane-overturning disaster last September in Saudi Arabia. The Liebherr that fell in KSA was a good deal bigger than the one that fell in New York, and it fell backward rather than forward, but from what I read, it had the same general rigging:


As with lowering the hook block to the street, lowering the jib goes far to reduce the crane's tendency to overturn. 

These two steps are particularly important when the crane lacks a trailer-mounted stack of counterweights. 

Due to the fatality the city's Department of Investigations will issue a report in months to come. 

Saturday, February 6, 2016

Another Large Crane Mishap, NYC

About the fatal crane accident in lower Manhattan yesterday, which happened while the operator was lowering the crane boom and jib to reduce toppling risks from a rising wind ...  From the sparse photos, this unit looks like a Liebherr LR1300, which wouldn't be counted as a supercrane. The crane was rigged for a long reach and light pick.



It was carrying a lot of mast and jib, 565 feet of it according to reports, but it must have handled such a dead load before, since crews had put the sections together on the ground, after which the operator raised it to position. 

Given that the car body flipped over on its back, I'd guess that the luffing cables didn't snap; that is, the falling mast and jib dragged the car body over on its back, with the rising counterweights providing the momentum. 

Some things the NYC investigators will look at: was there extra weight on the hook, mast, or jib that would have overbalanced it; did the pavement collapse under the front of the tracks? I assume that the crane had been sitting on timber mats, but I can't tell from the photos, which show the crane after it overturned. Mats are important to keeping big cranes upright. 

Kudos to news reporters that call this a tip-over rather than a collapse. When a structure falls intact, as this crane apparently did, I wouldn't call that a collapse. 

Second note to reporters: nearly all the photos posted are of the mast and jib in the lay-down zone. Yes, these tell us the tragic damage such a machine can cause, but it doesn't convey much information compared to a close look at the car body, undercarriage, counterweights, crane mats, and hoist rigging. 

Terminology for big crawler cranes like this is available in my post about the crane tip-over near the Grand Mosque at Makkah.

Also, here's a reposting of my item "How to Park Your Super-Crane," fixing a broken photo link.