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26 February 2010

Recent Aviation Safety Events and the Role of Sound

The past few days have seen three separate aviation safety related events that all have one surprising thing in common, sound. The most recent is the only one that was not connected with a fatal airplane crash, but could have a very significant effect on airline procedures in the future.

NTSB Recommends Routine Analysis of CVR Data
As reported by the USA Today and other media sources, (see pages 47 and 59), the NTSB made a recommendation (number A-10-29) which asks that the appropriate regulations be changed to allow airline operators to routinely "download and analyze all available sources of safety information, as part of their flight operational quality assurance program, to identify deviations from established norms and procedures; (2) provide appropriate protections to ensure the confidentiality of the deidentified aggregate data; and (3) ensure that this information is used for safety-related and not punitive purposes"

In plain English, the NTSB is recommending that airlines be allowed to review information from the cockpit voice recorder (CVR) to help improve safety. At, we're having a hard time understanding this recommendation. While reviewing cockpit conversations may provide crucial insights that may prevent future incidents and accidents, and such reviews have been used with very positive results in past accident investigations, doing so routinely may not be so beneficial. One big issue is logistical, and two immediately come to mind, how to choose what to review, and how to record the most useful information.

A bigger problem is technological. Currently, cockpit voice recorders in the US are required to at least the last 30 minutes of cockpit conversation. Some record up to two hours, and in 2012 all will be required to record for at least two hours. However, the average airliner may spend many more hours per day in the air. Even if recorders are reviewed at the end of every day, most recorders would likely have only the most recent flight, and only the last part of the flight. Unless the NTSB is also suggesting a radical change in voice recorder technology and procedures to include enhancing the capability to record all conversations all the time, it is hard to see how reviewing a fraction of routine cockpit recordings can be either useful.

The other two audio related aviation events involved two very different crashes of private aircraft. The first was the February 17, 2010 crash of a Cessna 310 into an East Palo Alto, CA neighborhood. Although all three on board were killed, and several houses severely damaged, no one on the ground was injured.

Fatal Crash in East Palo Alto
The city of East Palo Alto, where the crash occurred, uses an advanced audio detection system that allows police to quickly find the locations of gunshots. This ShotSpotter system recorded the sounds of the crash from two locations. According to the NTSB, these recordings will be used in their investigation, and is the first time that such a recording will be used for forensic purposes.

Recordings taken from two of the sensor locations are below. While they may be useful for the investigation, they also represent the sound of three people being killed and a neighborhood in peril. Both begin with the sound of a plane's engines, followed by the sounds of the aircraft hitting power lines, and then followed by crashing and banging sounds as parts of the aircraft hit homes and cars. In one of the recordings, you can clearly hear the screams and cries of terrified residents as the plane struck the neighborhood.

Sounds of plane crash alone

Sounds of plane crash plus screams of neighbors

Aerial Attack in Austin
The day after the crash in East Palo Alto, Joseph Stack, who apparently had serious tax issues with the IRS, allegedly flew his aircraft into a building housing several IRS offices, severely damaging the building and killing one person inside.

Less than 20 minutes before this crash, and less than an hour after allegedly setting his own house on fire, the pilot took off from a Georgetown Municipal airport, a small airport north of Austin, and had what sounded like a normal conversation with air traffic control.

Listen to ATC clearance for Joseph Stack (Source:

What Does It All Mean?
Audio happened to connect these three events, but the message here may not be about audio at all but about technology. As the two private plane crashes showed, technology is reaching into more and more areas of everyday life, and will likely play an increasingly important role in how the public experiences aviation safety events and variety and sophistication of data available to crash investigators.

In the case of the two crashes, the audio technology existed for different purposes and just happened to record part of the flight of an accident aircraft. It is no different than the way that security or traffic cameras near airports sometimes happen to catch a dramatic event like a plane crash. The decision of the NTSB may not represent a policy shift within the aviation community as much as it represents an evolution of how the aviation safety community views the ways that existing technologies can be used to enhance safety.

18 February 2010

Man Deliberately Crashes Plane into Building in Austin

A small aircraft crashed into an office building in Austin, Texas. The crash was apparently a deliberate act. The building contained offices of the US Internal Revenue Service (IRS), and the pilot involved in the crash had a long and contentious relationship with the IRS. The pilot, Joseph Stack, had set fire to his house earlier, and had left a detailed letter on his web site that implied violent threats against the US government.

Stack's house caught fire at about 9:15 a.m. According to the FAA, the plane, a single-engine Piper Cherokee PA-28-236 Dakota (N2889D), took off from the Georgetown, TX municipal airport at 9:40 a.m. The crash site was about 20 miles (32km) SSE of the airport and the crash happened at about 10 a.m. The pilot and one person in the building were killed in the crash. At least one person in the building was seriously injured and airlifted to a burn center in San Antonio. About a dozen other building occupants were injured.

Austin police chief Art Acevedo stated that the crash “appears to be an intentional act, appears to be by a sole individual, and it appears this individual was targeting federal offices inside that building.” Numerous witness accounts were also consistent with a deliberate flight into the building.

Relevant Airline Security Issues
After the attacks of 9/11, the US government added multiple security measures affecting commercial airliners and private aircraft. While private aircraft face significant restrictions in the airspace around some areas, most notably the Washington, DC area, most areas have had no significant changes in procedures.

The airport used by Joseph Stack is a general aviation airport, and like most such airports there is no permanent security provided by TSA or any other federal agency. When the control tower is closed and the gates of the airport are closed, there is a system in place to allow anyone to gain access to the airport simply by driving through an automated gate. Security is mostly in the hands of airport users, who are encouraged to report unusual security situations.

Listen to ATC clearance for Joseph Stack (Source:

Notable Crashes of Small Aircraft into Buildings
12 September 1994 - After spending an evening with his brother consuming alcohol and smoking crack cocaine, Frank Eugene Corder, who was not a licensed pilot, stole a Cessna 150 and crashed into the South Lawn of the White House complex, with some parts of the airplane hitting the White House residence and causing minimal damage. Corder was killed, and no one else was injured.

5 January 2002 - A 15-year-old boy, who was not a pilot, stole a Cessna 172 and flew it into an office building in Tampa, FL. The pilot was killed and no one else was injured.

18 April 2002 - A Rockwell Commander 112 aircraft crashed into the Pirelli Tower in Milan Italy, killing the pilot and two others in the aircraft. A suicide was suspected, but not conclusively proven.

11 October 2006 - An aircraft carrying New York Yankees pitcher Cory Lidle and his flight instructor crashed into a 50-story building located in the upper east side of Manhattan. One person on the ground sustained serious injuries, two people on the ground sustained minor injuries, and the airplane was destroyed by impact forces and post crash fire.

Austin, Texas office building before the crash

Austin, Texas office building after the crash

Aerial view of crash site

Fire rages at crash site

Video of Still Smoking Building

Photo Credits: Jeff Lake, Austin American-Statesmen, Google Earth

09 February 2010

The PBS Frontline Story "Flying Cheap" Airs Tonight

Tonight, the PBS show Frontline will air an airline safety oriented episode, "Flying Cheap," that focuses on the factors that led to the February 2009 crash of a Continental Connection airliner near Buffalo, NY. The flight was operated on behalf of Continental by Colgan Air, a regional carrier that flies routes under contract for US Airways, United and Continental.

This show provides a glimpse into the lives of regional airline pilots through interviews with former Colgan Air pilots. The overall argument of the show is that the rise of regional air carriers has benefited airline passengers by driving down prices, but at the possible cost of increasing safety risks.

Broadcast times will vary, so check out your local broadcast or cable listings. If you dont' have access to PBS, you can also visit this episode's web site out the PBS's web site for this episode. You can see an 11-minute excerpt from the show below:

Related Resources details on the Continental Connection crash
NTSB Conclusions on the causes of the Continental Connection crash article on how much money pilots make
LA Times story on overworked and underpaid pilots

08 February 2010

Possible Major Security Breach at JFK - Stowaway Found in Wheel Well

A mechanic at Tokyo's Narita airport found the dead body of an apparent stowaway in the wheel well of a Delta Air Lines 777 that had recently arrived from New York's JFK airport. According to CNN, Delta Flight 59 had departed JFK at about 12:53 pm on Saturday February 6th, and arrived in Tokyo at 4:46 pm local time on Sunday. According to the Mainichi Daily News, the body was found about 80 minutes after the airplane landed. There was no identification on the body, and Japanese authorities are trying to identify him. The body reportedly had no visible injuries except for signs of frostbite.

The wheel well area of the 777, like that of most jet airliners, is unpressurized and unheated. Temperatures can fall well below -40 degrees during a flight, and can stay that low for several hours. Also, there is not enough oxygen at high altitudes to prevent hypoxia, and that alone can be fatal.

There is no way to access the 777 wheel well from the passenger cabin, and it is highly likely that the stowaway got into the wheel well at a previous departure airport. If that airport turns out to be JFK, this represents a very serious breach of security because it demonstrates that it is possible for someone to get close to an airliner on the ground without being stopped by security or by other airport staff. As is the case with entering the secure part of an airport terminal, no one is allowed to access to the airport apron or runway areas without authorization and without passing through some kind of security.

If it turns out that the stowaway got into the aircraft at a prior departure airport, it would still represent a potentially catastrophic lapse of security since it would imply that routine maintenance and security checks between flights would have been unable to find something as large as a man that was hidden in a wheel well.

So far, Delta, the airport authority that runs JFK, and the US Department of Homeland Security have not made any formal statements about this apparent security matter.

Reports of stowaways in jet airliner wheel wells are fairly common, typically involving someone from an economically challenged country attempting to fly to western Europe or North America. Unlike fatal events involving passengers, crew members, or airport ground personnel, deaths to stowaways are not routinely tracked by national or international civil aviation authorities. Given the heightened danger from individuals and groups intent on destroying airliners, it would make sense to treat all stowaway events as serious security matters that should be both tracked and investigated by the appropriate authorities.

Related article from Business Week

03 February 2010

NTSB Blames Crew in February 2009 Buffalo Crash

During a public meeting on February 2, 2010, the NTSB adopted a report on the February 12, 2009 crash of Continental Connection flight 3407 that determined that the captain inappropriately responded to the activation of the stick shaker, which led to a stall from which the airplane did not recover.

The aircraft was a Bombardier Dash 8 (N200WQ), and was flying as a Continental Connection aircraft, though it was operated by Colgan Air. On the night of February 12, 2009, it was on a scheduled flight from Newark, NJ to Buffalo, NY and crashed in a residential area about five miles (8km) from the airport. One house on the ground was destroyed. All 45 passengers and four crew members were killed, along with one person on the ground.

Their report stated that during approach, when the stick shaker activated to warn the flight crew of an impending aerodynamic stall, the captain should have responded to the warning by pushing forward on the control column. However, the captain inappropriately pulled aft on the control column and placed the airplane into an accelerated aerodynamic stall from which the crew could not recover. The NTSB also identified as probable causes the flight crew's communications procedures, the captain's ineffective management, and the airline's procedures for airspeed selection during approaches in icing conditions.

This investigation has generated substantial public interest over the past year in part because of issues, that may have contributed indirectly to this accident, including crew fatigue and the related issue of pilot pay. The captain commuted hundreds of miles and the first officer commuted from the other side of the country prior to reporting for duty, and the NTSB concluded that both pilots used an inappropriate facility during their last rest period before the accident flight. The NTSB also concluded that the pilots’ performance was likely impaired because of fatigue.

The synopsis of the accident investigation report is currently available, and the full report will be available in a few months. In the meantime, the public can review a wide variety of information, including the public docket, which contains testimony, exhibits, and other information used by the NTSB during the investigation.'s Initial Report on this Accident
Audio: MP3 | VideoiPod/MP4 | WMV | Google Video | YouTube

NTSB Accident Animation
The following NTSB animation of the last few minutes of the flight shows excerpts from the flight data recorder (FDR), the cockpit voice recorder (CVR) transcript, recorded radar data, and aircraft performance data. The audio portion of the video is from air traffic control communications, and does not include audio from the cockpit.

Additional information about this event
Synopsis of NTSB accident investigation
NTSB press release on the accident report
NTSB public docket on the investigation
Colgan Air input to the NTSB investigation
Previous Continental crashes
Other Dash 8 events
Continental Airlines Wikipedia page
Continental Express Wikipedia page
Continental Connection Wikipedia page
Continental fleet
Continental Express fleet
Colgan Air fleet YouTube channel