I did some more digging, and unbelievably, it appears everything was actually real, except where they let the bus down on the rooftop (and the crash into the building was faked of course too, as per the photo in the question).
Jeff Mann, who collaborated with director Dominic Sena on Gone in 60
Seconds (2000) and many of his music videos and commercials, was
instrumental in creating the film's finale - an incredible stunt
involving a Sikorski helicopter and a bus full of hostages. "At the
climax of the film, Gabriel has loaded the hostages on the bus and
they are surrounded by SWAT teams," Mann explains. "There doesn't seem
to be any way out. I envisioned a spectacular escape that Gabriel and
his operatives would have planned months before. This massive sky
crane appears like some huge insect and swoops down, plucking them off
the ground and depositing them on the roof of a skyscraper. "
At the time Mann pitched the idea to Sena, they didn't know if it was
actually feasible to do the scene physically. "When we started to do
the research," says Mann, "we were taking a 7,000-pound liberty. "
Mann met with representatives from Erickson Sky Crane, a firm that
specializes primarily in putting out fires, transporting lumber and
positioning large air conditioning units on very tall buildings. To
execute such tasks, the company designed a custom rig that
counter-balances and stabilizes heavy equipment so it doesn't twist
dangerously while being hoisted through the air.
After numerous discussions, the filmmakers decided that it was
feasible to fly a bus through downtown L. A. using the special crane,
but there were too many liabilities and insurance issues to set the
bus down on an actual rooftop. After initially considering a graphic
solution, it was decided it would be simpler to build a rooftop set.
Mann created an exact replica of a downtown rooftop and built it in
the mountains above Chatsworth. One of the considerations in choosing
the location was that they needed a clear vista looking west and
In order to pull off the unprecedented flying bus stunt, explains Boyd
Shermis, "We did a pre-visualization of the bus's flight path by
creating a very detailed version of the area, in a virtual sense, so
we could literally put ourselves on top of any number of buildings
along that pathway and know exactly what we were going to see and how
we could place the cameras. "
Shermis placed a virtual camera on just about every rooftop along the
bus's flight path and was able to give director Sena a range of
options in terms of their positions and lenses. "There were legions of
cameramen," says Sena. "It was sort of like Napoleon's army. We had 14
or 16 cameras shooting at a time. "
The day finally arrived and the filmmakers' dream became reality. The
massive sky crane sat in a downtown parking lot as the crew looked on
expectantly. As the rotor blades began to rotate, an ungodly noise
filled the air and spectators covered their ears. The huge machine
slowly rose and dust and debris filled the air. It hovered above the
bus as the cables were attached. As it swept by base camp, a violent
wind buffeted the onlookers and they turned away covering their faces
trying to stay upright as the wind reached almost hurricane force.
"This thing would knock you to the ground and just hold you there,"
Sena notes with a laugh. "The rotors seemed to be about 80 feet
across, and the rotor wash was devastating if you were under it. I
made the mistake of doing that once as it was hovering to take off on
North Hope, and it just sucked the breath out of my lungs. "
The following Sunday, the bus was hoisted up from the 1st Street
Bridge and flown through the downtown streets of Los Angeles. It was
lifted to building height, which is about 15 stories from street
level, and traveled down the street in close proximity to the adjacent
buildings, sometimes with a mere 40 inches on either side. Cameras
were set on platforms on the edges of skyscrapers and as the sky crane
made its turn, the bus swung in a curve within a few feet of the lens.
"This is a sequence that could have been done with CGI, but we felt it
was important to actually do it live; nothing like this has ever been
seen before, and that cutting-edge feeling was what we were after with
this movie," Silver enthuses. "We wanted to make it bigger, better,
more exciting and thrilling and give people a real wild ride. And if
we've done that, then we've done our job. "
Safety was obviously the primary concern, and although the majority of
the flying bus sequence was a physical effect, some elements were
turned over to the visual effects team. There was a certain amount of
blue screen work involved, mainly for the interior of the bus and the
view from inside the bus. (In the story, the hostages are still inside
the bus when it is airlifted through the canyons of the city. ) A blue
screen was erected at the TWA hangar at Los Angeles International
Airport to accommodate the huge set. The bus was hung 60 feet off the
ground from a crane so it could swing free.
The interior shots presented a challenge for stunt coordinator and 2nd
unit director Dan Bradley. "What I needed to do was to match the
energy inside a bus flying throughout downtown L. A. in a hostage
situation," Bradley relates. "We needed people to react in broader
ways. " Bradley spent days working out the logistics with special
effects coordinator Michael Meinardus.
One of the most important things to determine was how much weight the
bus would hold. "We did test after test," says Bradley. "As the bus
dropped, everybody goes weightless and we needed to create that
effect. As the bus traveled through its arc, they got a lot of
negative and positive G's, floating out of the seats, starting to
crawl back. Then when it hit the bottom of the arc, they're turned
upside down. It's very disorienting. "