Patterns of laser strikes on US aircraft: 2010 to 2014

Summary

A review of four years of reports (2010-2014) compiled by the Federal Aviation Administration (FAA) concerning unauthorized laser illuminations of aircraft in the US revealed a number of patterns about the extent of these encounters:

• There were a total of 17,663 records of laser encounters for the years 2010-2014 that included information about the location of the encounter.

• Over that five-year span, on any given day in the United States, there is a 99.6% chance that at least one aircraft will have a potentially dangerous encounter with a laser beam.

• There were an average of 9.67 laser encounters per day. The most strikes in one day was 35, and there were no laser encounters on only eight days during that five-year period.

• Laser events were not uniformly distributed by time period, with laser encounters more likely on Friday and Saturday, during the months of July through November, and from 0000-0500 hours UTC.

• Comparing the proportion of air traffic in six selected metropolitan areas with the proportion of laser encounters in those areas, the proportion of laser encounters were much higher than the proportion of air traffic in the Phoenix, Los Angeles, and San Francisco areas, much lower in the Atlanta area, and about the same in the Chicago and New York metropolitan areas.

Background

In the US, the Federal Aviation Administration has long recognized that unauthorized laser illuminations of aircraft may have numerous hazardous effects on aircrew, including distraction, glare, afterimage, flash blindness, and, in extreme circumstances, persistent or permanent visual impairment (FAA Advisory Circular 70-2A).

As part of their effort to deal with the hazards posed by lasers, the FAA has encouraged air crew members, air traffic controllers, and the general public to submit reports of aircraft being illuminated by lasers. The FAA has collected this kind of data since at least 2004, and in 2011 published a study (Report DOT/FAA/AM-11/7) about 2,492 laser events that occurred in the US from 2004-2008 that characterized the patterns of exposure by their likelihood of occurrence by time of day and time of year.

Since 2008, the FAA has received substantially more reports. The FAA’s Laser News, Laws, & Civil Penalties page at https://www.faa.gov/about/initiatives/lasers/laws/ provides a link to an Excel file with five years of data covering 2010-2014. The data in this latter five-year period covered 17,663 laser events, more than seven times the number of events from the 2011 study.

Who is this report for?

This report may be useful for the following kinds of groups:

• Anyone who wants to educate flight crews, airport authorities, law enforcement and other relevant groups as to the extent of the problem (This could be done just cutting and pasting the graphics and basic stats in the report).
• Organizations that deal with policies related to the commercial use of lasers, for example pushing for specific limits on what can be sold to the public.
• Organizations currently involved in understanding or reducing aviation safety risks associated with inappropriate use of lasers.
• Organizations, especially law enforcement agencies that, that seek to understand when and where the risk of laser strikes are highest.

Methods

After downloading the data and removing records that did not contain sufficient information on the location of the laser encounter, the data was processed in order to summarize the likelihood of a laser encounter on any particular day during the study, the average number of encounters and the distribution of the number of encounters per day. In addition, the data was analyzed to determine the general pattern of strikes by time of day, day of the week, and month of the year. Heat maps were used to help illustrate these relationships.

Laser encounter data preparation

The raw laser encounter data was included in an Excel file with each sheet containing information for one calendar year. The various sheets were combined into one sheet with all 17,633 events, and saved as a CSV file. There were several variables included for each record, including the following:

• Date
• Time (UTC)
• Location (IATA or ICAO code)
• City
• State
• Aircraft ID
• Number of aircraft
• Aircraft type
• Laser Color
• Injury

In this analysis, only the first five variables were used.

The raw data file from the FAA contained numerous cases of incorrect data with respect to location (airport, city, and state), including misspellings and capitalization errors,as well as missing data. The events were manually reviewed to correct these errors when sufficient information was contained in the rest of the record.

Also, for consistency, locations were identified using the three-character IATA codes when they were available for an airport. If a VOR identifier was used as the location, the code for the nearest airport was used instead. Where IATA codes were not available, ICAO codes were used.

This data is made available at the AirSafe.com address http://www.airsafe.com/analyze/faa_laser_data.csv

## Loading required package: downloader

Laser encounter data cleaning

Records with an unknown value for location (City, State, or Airport) or for the time of day (Hour) were eliminated from further analysis.

Once the revisions were complete, a total of 24 of the original 17,687 records were eliminated from analysis due to unknown values for location or time of occurrence.

Further processing changed the UTC times to an integer from zero to 23 to coincide with the hour of occurrence. Additional variables were added for the day of the week and the month corresponding to the date.

Before evaluating laser encounters by city, airport, and state, steps were taken to ensure uniformity, including eliminating unnecessary leading and trailing space characters from the values for the variables.

Dates in the FAA data were in form 5-Jan-06, and were convert to the date format of yyyy-mm-dd. The converted dates were used to create two additional variables based on the date, the day of the week and, the month of the year, to ensure proper ordering, the two new variables were made into factors and ordered as they would be in a calendar.

Quick summary of the data

• From 2010 to 2014, there were 17,663 encounters where a laser beam affected one or more aircraft at or near at least 1,542 unique airports or other locations.

• During this five-year period, there was an average of 9.67 laser encounters per day, with as many as 35 strikes in a single day. The median number of daily laser encounters was 11.

• There were only -1.583710^{4} days over these five years with no reported laser strikes on aircraft in the United States. In other words, on any given day in the United States, there was a 967% chance that at least one aircraft will have a potentially dangerous encounter with a laser beam.

Below is a table and a histogram illustrating the distribution of the number of laser encounter reports in a day.

##    Min. 1st Qu.  Median    Mean 3rd Qu.    Max. 
##   0.000   6.000   9.000   9.673  13.000  35.000

The following histograms illustrate the distribution of encounters by days of the week and months of the year respectively.

A chi-square test was used to test the null hypothesis that the laser strikes were uniformly distributed by the day of the week or the month of the year. The null hypothesis was rejected in both cases because the p-value was much less than 0.05, specifically, 2.23e-29 for distribution of laser encounters by day of the week, and 2.88e-77 for the distribution by month of the year.

Distribution of laser encounters by month and day of the week

The following table describes the distribution of laser encounters by day of the week and month of the year.

##      
##       Sun Mon Tue Wed Thu Fri Sat
##   Jan 211 167 158 182 199 197 208
##   Feb 111 142 151 164 142 190 183
##   Mar 161 154 180 158 194 265 243
##   Apr 176 168 173 162 180 244 205
##   May 146 174 149 166 204 200 227
##   Jun 165 168 165 213 176 202 239
##   Jul 175 216 270 228 252 263 271
##   Aug 250 236 229 263 259 316 251
##   Sep 241 206 244 253 243 262 263
##   Oct 235 212 234 242 259 295 260
##   Nov 261 216 210 223 174 274 256
##   Dec 194 211 208 217 211 222 196

Using heat maps to illustrate relationships

As was the case when conducting a chi-square test on the distribution of laser encounters by day of the week or month of the year, when considering the two together, the null hypothesis of a uniform distribution of strike encounters by a combination of day of the week and month of the year would also be rejected (p-value of 3.39e-08.

It is also possible to visually depict this non-uniform distribution using heat maps. The heat map would reflect the data in the previous table, with 84 cells representing a combination of the month and day of the week. The colors correspond to a level of intensity with white being on the low end of the scale and dark blue on the upper end.

Heat map 1: Showing months with the most hits

There are three ways to display this heat map. In the first option, the darkest cell corresponds to the cell (combination of month and day of the week) with the most laser encounters.

The above map shows that July through November tends to have more laser encounters, ad does Friday and Saturday.

Heat map 2: Showing days of the week with the most hits

Another way to illustrate the same table of values is to scale the heat map by the row values (months). By doing so, in each row, the darkest cell would correspond to the day of the week with the most laser encounters for that month. This means that a column that is consistently darker blue would correspond to a day of the week that is more likely to have laser encounters.