Tom Haines

Putting deadly August to bed

September 1, 2011 by Thomas B. Haines, Editor in Chief


August marked the anniversary of two remarkable aircraft accidents, the affects of which we feel on every flight, even 25 years later.

On August 31, 1986, a Piper Archer and an Aeromexico DC-9 collided over the community of Cerritos, California, killing all 64 on the airliner and the three occupants of the Archer. In addition, 15 people on the ground were killed and five homes destroyed and seven damaged by fire and falling debris. The Archer was squawking VFR with a Mode A (non-altitude-reporting) transponder and inadvertently penetrated the bottom of the Los Angeles Terminal Control Area (today we call that Class B airspace).

The accident led to the mandate for Mode C (altitude-reporting) transponders around Class B airspace and even beyond the Class B borders in what is known as the Mode C veil. The convulted airspace around Los Angeles is in part also a result of the Cerritos accident, as ATC attempts to separate loads of airline and GA traffic around dozens of airports.

I worked for an independent aviation magazine at the time and remember the remarkable effort by AOPA public relations staff to attempt to protect GA from onerous new regulations. Any time people on the ground are injured or killed from an aircraft accident, the potential for knee-jerk regulations escalates. Killing 15 on the ground was unprecedented. The media frenzy went on for months and AOPA staff worked admirably through it all, advocating for reasonable changes that improve safety without compromising the ability to take advantage of the versatility and utility possible with GA aircraft.

Discussions of requirements for airliners to carry collision avoidance systems was already underway, but the Cerritos accident escalated that talk. The TCAS mandate followed quickly, and today all airliners and many GA aircraft carry such systems.

Fortunately, discussions to require Mode C transponders in all types of airspace at all times–even from aircraft without electrical systems–calmed with time and thanks to AOPA’s input. The debate about the Mode C veil would continue for years before finally being implemented in the late 1980s.

However, what we learned about collision avoidance from Cerritos pales compared to what we learned about microbursts from the Delta Airlines accident at Dallas-Fort Worth International a year earlier on August 2, 1985. The Delta L-1011 was en route from Fort Lauderdale to Los Angeles with a stop in Dallas. On approach to DFW, the airliner tangled with a thunderstorm that slammed it into the ground, killing 8 of 11 crew members and 126 of the 152 passengers as well as one person on the ground. A massive investigation showed that the airplane encountered a little understood windshear phenomenon that became to be called a “microburst.” Essentially, a large burst of air near a thunderstorm that slams into the ground, robbing an airplane on approach of critical airspeed.

As a result of that accident, we soon saw the development of low-level wind sheer alert systems at major airports, more sophisticated algorithms in next-gen weather radars that look for microburst signatures, and new generation airborne weather radars that also seek to alert to microbursts and turbulence. In addition, training scenarios were established to help pilots recognize microburst situations and escape from them.

Here’s hoping we continue learning from such accidents and see no more of them.

Tags: , ,

6 Responses to “Putting deadly August to bed”

  1. Ken Howell Says:

    Rather than the “sole occupant”, as stated, there were in fact three occupants of the Piper involved in the collison over Cerritos, the pilot, his wife, and their daughter. Errors in content tend to bring into question the integrity of the whole article. A little more fact checking would be advisable.

  2. Tom Haines Says:

    Ken, Thanks for the correction. The NTSB report confirms you are correct and I have updated the blog to reflect the right information. I appreciate you pointing it out.

  3. Rol Murrow Says:


    Thanks for the reminder about the important lessons we learn from tragedies!

    I know your article had to be short but thought a few more “lessons learned” and outcomes are worth mentioning regarding the Cerritos accident:

    1) The NTSB, while finding that all the participants in the accident made mistakes, including the Aeromexico crew, the Archer pilot, and the controller, the problem was found to be the ATC system as designed and managed by the FAA. In fact the “system” was really a hodgepodge of system “upgrades,” fixes, and other band-aids that had accumulated over decades, rather than a proper system appropriate for the airspace in question – or elsewhere.

    2) FAA compounded its error almost a year later by summarily closing the VFR corridor over LAX causing a flurry of near midair collision reports and tremendous disruption of traffic throughout Southern California.

    Following a massive protest by area aviation groups FAA Administrator Alan McCartor met with users and agreed that the problem was with the system and that the closure only led to worse problems. Ultimately that dialogue, with support from AOPA, led to the system of creating user groups across the country for dealing with airspace design and implementation.

    The first was the Southern California Airspace Users Working Group, which was instrumental not only in adding new VFR routes to the L.A. airspace, but also making a number of comments regarding the Reclassification of the nation’s airspace, which were supported by AOPA and most of which were adopted by FAA.

    Keep up the good work! – Rol

  4. Jason Says:

    This was a great blog entry. I encourage you to continue this theme. For us newer pilots, we sometimes grumble about all the regulations we must learn and commit to memory. The context provided by stories like this elevates that rote memorization up to a fuller comprehension. By understanding the price paid in blood by others, I have a deeper respect for the regulations I get to safely learn myself.

  5. Michael Perdaris Says:

    I found this an interesting post. My father was in seat 28J on flight 191 and did not survive. I was 6 years old at the time. Since then, my fascination with aviation has overcome my fear of it. I am now a 3,600 hr ATP and fly professionally as a corporate pilot, and have flown as a charter pilot in King Airs and Citations. I would be interested in seeing additional space devoted to this accident, as it was a turning point in wind shear detection equipment. I have also been told that there are simulation programs based on this accident, and I would like very much to have an opportunity to experience this scenario first hand.

  6. computer support Says:

    Today, I went to the beach with my children. I found a sea shell and gave it to my 4
    year old daughter and said “You can hear the ocean if you put this to your ear.” She placed the shell to her ear and screamed.
    There was a hermit crab inside and it pinched her ear.
    She never wants to go back! LoL I know this is completely off topic but I had to tell

Leave a Reply