(Editor’s Note: TVB is presenting this 2003 interview with Mohammad Ayub in the wake of a
viral video showing a technician free climbing a 1,768-foot structure. Ayub was the OSHA
official who investigated several tower-related fatalities at the time. TVB
has no desire to ever report another such fatality.)
by Deborah D. McAdams for TV Technology
October 29, 2003
WASHINGTON: It beggars the imagination to think of a 1,000-foot television tower as
fragile, but last month’s tower collapse near Huntsville, Ala., was another
reminder that these structures can come down in the blink of an eye, with
tragic results. Three men working on the 985-foot WAAY-TV tower were killed
when it fell to the ground on a calm, clear afternoon.
It was the fourth fatal tall-tower collapse since Oct. 12, 1996, when a
1,500-foot tower came down in Cedar Hill, Texas, killing three people. One year
later, on Oct. 23, 1997, a 1,889-foot tower collapsed near Raymond, Miss.,
taking three lives. Last year, on Sept. 24 near Hemingford, Neb., two workers
were killed in the collapse of a 1,965-foot tower.
In each incident, a team of investigators from the Federal Occupational Safety
and Health Administration (OSHA) was sent to investigate the cause. In each
incident, Mohammad Ayub led the team. Ayub is the director of the Office of
Engineering in OSHA’s Directorate of Construction. He agreed to talk with
TV Technology about his findings.
It should be noted that while Ayub is actively investigating the Huntsville
collapse, his responses are based on the previously closed cases. OSHA’s
findings on the Huntsville collapse are not expected until early next year.
It should also be noted that Ayub’s findings point to a dearth of proper
training among tower wranglers. Subsequently,
TV Technology contacted several companies that do tower
modification and repair to inquire about training standards, and found a dearth
of responses. Understandably, the industry is mum in the wake of the Huntsville
collapse. That tower was owned by SpectraSite Broadcast Group in Irving, Texas,
and being modified by a team of SpectraSite workers. SpectraSite attorneys have
effectively muzzled the company’s officials, some of whom are considered by the tower brethren to be among the most safety-conscious in the business.
What are OSHA’s basic requirements for broadcast tower safety?
: OSHA does not have, per se, a TV antenna tower safety requirement.
All we expect is that they follow basic engineering principals and standard
practices. Any worker climbing up a tower needs to have fall protection.
Have OSHA investigators identified similar factors among the
tall tower collapses since 1996?
: Yes, we have-a lack of understanding of the behavior of the tower
on the part of the workers. They really fail to understand how the tower
behaves and what makes it stable.
Most of the modifications are being done to install new DTV antennas, and they
weigh much more than old antennas ... so the tower needs to be upgraded. Most
of the time, upgrading involves replacing diagonals, or horizontal members, and
sometimes guy wires. If they don’t understand that each member is so critical
for the stability of the tower, they will just remove a horizontal member
without using a replacement [such as] a come-along -- a wire rope -- which can
be attached to the tower to take place of the horizontal member.
They are not doing that.
Other times, they will also take away two or three diagonals at a time,
weakening the tower. They need to replace only one diagonal at a time, using
either a come-along or a frame -- a 9-by-10-foot structure that attaches to the
Is geography, season or age a factor in collapses?
All the towers have been designed up to a certain standard. Even in the face of
high wind or snow, or ice forming on the guy wires or on the structural
members, there is enough structural safety built in that it should not just
It might fail if structural members become weak due to the corrosive damage.
Then if there’s wind or ice, it might have some impact. But as a general rule,
Is the digital
television transition a factor in these tower collapses?
: Most of the modifications to the existing towers are being done
because of the new antennas, but I wouldn’t say [digital television] is a
factor in the collapses.
Do OSHA engineers regularly inspect broadcast towers?
AYUB: OSHA compliance officers only inspect if there are problems,
or if there are complaints from employees or contractors, or if there is an
Who does the broadcast tower inspections?
AYUB: Inspections are done by private consultants, hired by tower
What should all crews do before repairing or upgrading a
: They should undergo training so they can understand the importance
of each member.
They should be shown, step by step, exactly how to replace the members, and
they should be cautioned that there is no redundancy in the tower. If you take
away one member of the tower, you might jeopardize the safety of the whole
Also, they should not use a gin pole unless a structural engineer has
determined if the tower can take the load. Gin poles weigh 8 to 10 tons, and
since they are attached only on one face of the tower, a structural evaluation
(Gin poles are used to raise antennas from the ground to the top of towers.
They are about 3-by-3 feet in diameter, and can be anywhere from 80 to 160-feet
long. The gin pole is raised on another temporary structure called the “track,”
which generally weighs around 1,500 lbs.)
They must be told how high the gin pole can be raised above the track.
Sometimes, we find the gin pole has been raised too high above the track. The
top of the gin pole may have to rise 80 or 90 feet above the tower, because these
antennas are also very tall.
They have to hang the new antenna from the top of the gin pole, and then slowly
bring it down on top of the tower. In one incident that we investigated, we
found that the gin pole was raised too high above the track. It became unstable
and fell off, and the whole tower collapsed. For extending the gin pole above
track, the rule of thumb is 50-50. If the gin pole is 160 feet long, don’t
raise it more than 80 feet above the tower.
What precautions should broadcasters take to prevent tower
: One of the major problems is that consultants who design tower
modifications do not address the manner in which modifications should to be
made. This is true for all construction-for buildings, even for bridges. They
leave it entirely up to the contractor, maybe due to insurance and liability
The construction consultant who does the drawings for tower modifications
should highlight that the diagonals and horizontal members are really critical
to the tower. We have been saying this for a long time.
Most tower workers are young people, 18 to 24. A young person may feel, ‘hey,
it’s a 2,000-foot tower. If I just take away two or three diagonals, what
should it matter?’ But if there’s a big warning on the drawing, saying, ‘watch
out, these diagonals and members are very critical,’ perhaps it would drive the