On the 25th of September, 1978, Pacific Southwest Airlines Flight 182 was getting ready to land
at San Diego International Airport. Its journey thus far had been uneventful. The day was
bright and clear, the pilots were in good spirits, and the aircraft was functioning
perfectly. Before it could safely come in to land, however, a tiny misunderstanding
and a brief lapse in protocol would lead to an incident that would claim the lives of
everybody on board, along with several others on the ground below.
Pacific Southwest Airlines Flight 182 – a Boeing 727 with 135 people on board – had
originated in Sacramento early that morning. At 09:00am, after a brief stopover in Los
Angeles, it was cruising through a clear blue sky towards San Diego International Airport
(which was, at the time, known as Lindbergh Field). Given that the airport had only a
single runway, the sky above it was a relatively busy bit of airspace, often occupied by multiple
aircraft circling while they waited for a chance to land.
On this particular day, Flight 182 was sharing the airspace above San Diego with at least
one other craft – a small, privately-owned Cessna 172 Skyhawk, with a learner pilot at
the controls. Under the supervision of a trained instructor, the student was practising instrument-only
landings. This involved repeatedly circling and approaching the runway to gain experience
of trying to land without visual input – something which pilots need to be able to do in in foggy
or otherwise low-visibility conditions. In order to simulate these low-visibility conditions,
the student pilot was wearing a hood – a darkened visor that allowed him only to look
at the instruments, and blocked his view through the windows of the aircraft.
It so happened that the paths of Flight 182 and the Cessna brought them into close proximity.
At 08:59am, San Diego Approach Control contacted the cockpit of Flight 182 and informed them
that a Cessna aircraft was in their vicinity. About 20 seconds later the First Officer and
Captain both confirmed that they could see the Cessna, and were told by San Diego Approach
Control to keep it in sight. The exact words used by San Diego Approach
Control were “maintain visual separation”. This specific instruction was important. In
telling the pilots of Flight 182 to maintain visual separation, the controller made them
responsible for keeping the Cessna in sight at all times, and manoeuvring their aircraft
to avoid it. However, cockpit voice recorder data shows
that the pilots of Flight 182 quickly lost track of the Cessna. While busy with other
flight duties, they briefly looked away… and by the time they looked back they found
it difficult to spot the Cessna against the patchwork of houses below.
Just seconds later the tower again warned the pilots of Flight 182 about the presence
of the Cessna. The Captain and the First Officer briefly debated the positon of the smaller
plane. “Is that the one we’re looking at?” said the Captain.
“Yeah,” replied the First Officer. “But I don’t see him now.”
Not being able to see the Cessna was significant. Since they couldn’t pinpoint it, they couldn’t
readily maintain visual separation. They should, therefore, have immediately informed the tower
that they had lost sight of the smaller aircraft. As the Captain of Flight 182 tried to do just
this, a fatal miscommunication occurred. The Captain radioed the Tower with the words,
“I think he’s passed off to our right.” Passed. The past tense here indicated that
the Cessna had left his field of view, and that he no longer had sight of it.
Thanks to a burst of radio static, however, the tower controller heard something altogether
different. “I think he’s passing off to our right.” The present tense gave the impression
that the Cessna was still within sight, and that as such the pilots of Flight 182 were
still able to maintain visual separation from it.
This simple difference informed what the tower controller did next. When a proximity alarm
sounded, he cancelled it. After all, as far as he was aware the pilots of Flight 182 were
still able to see the Cessna, and were maintaining a safe distance from it. The controller made
a courtesy call to the Cessna to let them know that this was the case, but provided
no further guidance for Flight 182. There was, at this stage, some uncertainty
in the cockpit of Flight 182… but in the absence of any further guidance they continued
with their landing. As they descended towards the runway, they unknowingly overtook the
Cessna. The small craft was no longer visible to them, and neither could the occupants of
the Cessna see the jet bearing down on them. Moments later, the two planes collided in
mid-air. The Cessna was severely damaged in the collision,
and dropped straight downwards, smashing into a road below with the loss of both people
on board. Meanwhile Flight 182 burst into flames. As the pilots fought for control their
last few words were caught by the cockpit voice recorder. The Captain radioed Lindbergh
Tower, informing them that they were about to crash, and also used the intercom to order
passengers to brace themselves for impact. Seconds later the cockpit voice recorder captured
one final utterance before power was lost – a voice, which might have belonged to
any of the men in the cockpit – saying the words, “Ma. I love you.”
While the Cessna had crashed in the middle of a road, Flight 182 instead ploughed into
a street of houses, resulting in total destruction. The impact was followed by a huge firestorm,
which swept through the quiet residential area. Every single person on board Flight
182 – 135 people in total – was killed on impact. Seven further people on the ground
were also killed, and nine were severely injured. The incident was particularly devastating
for Pacific Southwest Airlines. In addition to the pilots in the cockpit, 29 other Pacific
Southwest pilots and staff members were on board Flight 182. The loss of so many colleagues
in one incident was devastating for everyone who worked at the airline.
The incident was also an extremely shocking one for residents in the area that was hit
by Flight 182. The absolute devastation had come from a clear blue sky, entirely without
warning, and struck a relatively peaceful and sleepy neighbourhood, turning it into
a warzone. In addition to the casualties from the disaster, 22 homes were destroyed, and
many people suffered significant psychological trauma.
The investigation which followed was long and painstaking. Its eventual conclusion was
that there had been mistakes on several fronts. The root cause of the disaster had been the
misunderstanding between the pilots of Flight 182 and the controller on the ground – a
misunderstanding that could have been avoided by a strict adherence to protocol, or by the
use of radar equipment that was already available at the airport.
As a result of the accident, the airspace around San Diego International Airport was
reclassified, with all air traffic that entered it now guided by radar. It was also one of
several incidents which contributed to the development and widespread use of the Traffic
Collision and Avoidance System. Installed on almost all aircraft above a certain size
the TCAS detects when a collision might be imminent, and provides an audible alarm for
pilots, along with instructions on how to avoid it.
A small memorial plaque to those who lost their lives in this disaster is located in
the San Diego Aerospace Museum. As a further legacy, the incident is now used as a case
study in the teaching of new pilots, vividly illustrating the importance of communication
and visual separation procedures. The collision of two aircraft in flight is
not a unique accident… and, especially around busy airports, it is more difficult to avoid
than one might imagine. With each incident that occurs, however, we learn more about
and put in place more measures to make it less and less likely. Although it’s too
late for the mistakes which lead to the crash of Flight 182 to be rectified, they can at
least not be repeated.