N508SW

Unknown
Minor

Boeing 737-5H4 S/N: 24185

Accident Details

Date
Tuesday, October 31, 1995
NTSB Number
LAX96IA032
Location
LAS VEGAS, NV
Event ID
20001207X04715
Coordinates
36.080738, -115.140838
Aircraft Damage
Unknown
Highest Injury
Minor
Fatalities
0
Serious Injuries
0
Minor Injuries
1
Uninjured
96
Total Aboard
97

Probable Cause and Findings

The flying pilot's inadvertent exposure to an unidentified ground-based laser beam. A factor in the incident is the lack of appropriate standards by the FAA and FDA for laser light exposure levels to aircrew in navigable airspace.

Aircraft Information

Registration
N508SW
Make
BOEING
Serial Number
24185
Year Built
1990
Model / ICAO
737-5H4

Registered Owner (Historical)

Name
SOUTHWEST AIRLINES CO
Address
2702 LOVE FIELD DR
HDQ-4GC
Status
Deregistered
City
DALLAS
State / Zip Code
TX 75235
Country
United States

Analysis

On October 30, 1995, at 1810 hours Pacific standard time, the first officer on Southwest Airlines flight 1367 sustained an eye injury when he was struck by what is believed to be a laser beam during departure from Las Vegas, Nevada. The aircraft, a Boeing 737-5H4, N508SW, was operated by Southwest Airlines, Inc., as a regularly scheduled domestic passenger flight from Las Vegas to San Antonio, Texas. Visual meteorological conditions prevailed. The aircraft was not damaged and there were no injuries to the passengers or other crew members.

The crew stated that the aircraft departed runway 25 at the Las Vegas airport at 1808 and was climbing through 7,000 feet msl (about 4,500 feet agl) on a standard instrument departure route when the incident occurred. The first officer, who was the flying pilot, said a laser beam swept past the cockpit from his left to right and he immediately experienced eye pain and was completely blinded in the right eye. He stated that the beam seemed to come from a point about 2 o'clock low reference his visual focus, which was on the flight instruments. After image effects also induced a blind condition in his left eye. He reported that the total inability to see lasted 30 seconds, and for an additional 2 minutes, he could not focus on or interpret any instrument indications. In addition to the vision problems, the pilot said that for several minutes he was completely disoriented in his spatial relationship to the vertical. The captain was not irradiated by the beam and was able to assume control of the aircraft and continue the climb.

Many of the larger hotels in Las Vegas have some sort of outdoor laser light show or demonstration. Most of these installations have both fixed/stationary (static) beams of relatively high power and "dancing" beams of lower power, which flash about the sky in irregular patterns. The majority of the hotels with "dancing beam" shows have voluntarily placed some azimuth and elevation limits to the beam travel in response to the on-going insistence of the Clark County airport officials and the Las Vegas area ATC management. The laser apparatus in use by the hotels can be adjusted in both power output and beam divergence angles and none has devices which record the parameters emitted or times of equipment operation. Some of the hotels have elected to terminate their laser output against walls or other hard obstructions.

Recorded radar data was obtained from the FAA Las Vegas TRACON depicting the aircraft's flight and altitude track from takeoff until reaching 14,000 feet msl. The data was provided to the Safety Board's Office of Research and Engineering, which performed a trajectory and vehicle attitude study to determine the relative position of several resorts with laser shows to the position and orientation of the aircraft during its assent. The radar data study is appended to this report.

A review of the air-to-ground communications between the aircraft and Las Vegas TRACON revealed that a routine exchange was conducted at 1811:35. At 1811:51, the crew transmitted, "We like to report a strike by that laser beam climbing out of seven thousand directly into the cockpit." Correlation of the radio transmission times to the recorded radar data reveals that at 1811:35, the aircraft was reporting a mode C altitude of 6,800 feet. Around 1811:51, the mode C report from the aircraft was between 7,500 and 7,800 feet.

The radar data showed that the aircraft departed runway 25 in a westerly direction and performed a right turn in accordance with the Mead Eight Departure to a 070-degree heading while climbing to 14,000 feet. According to flight crew statements, the laser beam encounter occurred at or slightly before the aircraft passed through 7,000 feet msl (about 4,500 feet above ground) in the climb. The trajectory and vehicle attitude studies show that as the aircraft passed through 7,000 feet, the positions of several resorts relative to the aircraft were all located in the clear vision field of view of the first officer, as defined by SAE Aerospace Standard 580B. Three of the resorts (Rio, Hilton, and Stratosphere) were at a position of less than 90 degrees relative azimuth from the first officer's eye reference point. Relative position calculations show that of the three resorts at a relative azimuth of less than 90 degrees, the Rio had the shortest three dimensional distance to the aircraft at 4.7 nautical miles. The Hilton and Stratosphere were at three dimensional distances of about 7 nautical miles.

The FAA Las Vegas Air Traffic Hub facility maintains a log of laser activity by the known hotel emitters which is based wholly on self reports by the hotels of their activity. The Hilton Hotel reported their "Lumenaria" display (dancing beams) was turned on at 1810 on October 30th and turned off at 0200 on the 31st. The Luxor hotel reported their laser show was shut down for technical enhancements during the entire evening of the 30th. All other hotel displays were reported as operational at the time of the incident.

During the investigation, Safety Board investigators met in Las Vegas with the Society of Automotive Engineers (SAE) G-10 laser subcommittee. The subcommittee is currently helping the FAA to formulate guidelines for approval of outdoor laser light shows and related airspace compatibility issues. In addition to the SAE committee members, representatives from FAA Air Traffic (both headquarters and the Las Vegas facilities), FAA Flight Standards, Food and Drug Administration, U.S. Air Force, Clark County (both airport officials and local police agencies), several laser manufacturers and one of the hotels conducting laser shows were in attendance. In addition, the irradiated pilot and several management officials from Southwest Airlines were present.

A general briefing was conducted by the G-10 committee on the history of this problem, the work done to date with the FAA to formulate airspace compatibility guidelines and a technical overview of lasers and their hazards. Following this, the irradiated pilot gave a first hand account of his experience. A videotape made by the Las Vegas Police air unit graphically depicted several laser beam encounters. For example, one static beam from the Hilton Hotel produces a 60-foot diameter circle of light on a mountain 12.5 miles away, with a clearly defined silhouette of the helicopter visible within the circle. The police pilot who flew the mission stated that at 10 miles, looking at the beam is "like looking directly into the sun." According to the pilot descriptions of encounters, in the clear air around Las Vegas the beams are largely invisible from the air until they are suddenly encountered.

At the meeting, a list (appended to this report) of 51 prior aircraft/pilot laser irradiations over the past 2 years in the Las Vegas area was presented by the airport authority and the local air traffic facility. The Air Force representatives from Nellis AFB indicated that an equal number of events have happened to their pilots in the area. Subsequent contacts with other air carriers and military authorities have revealed incidents in Miami, Orlando, New York, Los Angeles, Mississippi, and along the Mississippi river near the Tennessee border. To date, no known permanent eye damage has resulted from an in-flight non-military laser irradiation event. According to aircrew reports, the encounters have so far consisted of everything from various levels of annoyance to startle and flash blindness effects to one or more members of the reporting crew. Several reports were noted of air carrier/military aircraft in cruise flight well above 30,000 feet encountering laser beams from Las Vegas which brightly illuminated the cockpits. Several air carrier and military pilots interviewed during this investigation stated their reluctance to officially report laser irradiation incidents for fear of potential problems with their medical certificates.

From a regulatory and licensing standpoint, the U.S. Food and Drug Administration, Center for Devices and Radiological Health, is currently the agency responsible for approving and regulating lasers used for entertainment and other displays. This is an outgrowth of the FDA's role in regulating lasers used in medical applications. An FDA representative stated that there are currently 200 active licenses for outdoor entertainment laser displays and the number is growing at an exponential rate. The FDA estimates there are over 1,200 laser manufacturers. The FDA representative to the Las Vegas meeting stated that outdoor entertainment laser displays have replaced search lights as the medium of choice for nearly everything from advertisements and store grand openings, to rock concerts and theme park entertainment shows. During the licensing application process, the FDA asks the FAA if they have any airspace compatibility objection to an outdoor laser display. The FAA must then say yes or no to the proposed license.

Chapter 34 of FAA Order 7400.2D in effect at the time of this incident contains guidelines for FAA personnel in the approval process for determination of whether a proposed outdoor laser light display is compatible with navigable airspace. The order defines two areas based in part on federal OHSA and FDA guidelines, the Nominal Ocular Hazard Distance (NOHD) and the Eye Safe Distance (ESD). NOHD is defined as the distance from the point source where the irradiance level in power and area footprint can cause permanent thermal damage to the retina. ESD encompasses all other irradiance exposures where biological damage to the eye should not occur. Approval requires only that the laser beam be classed as ESD in navigable airspace. The approval process does not consider such laser exposure effects as flashblindness, afterimage, startle and high glare conditions on pilot performance.

The U.S. Air Force Armstrong Lab at Brooks AFB...

Data Source

Data provided by the National Transportation Safety Board (NTSB). For more information on this event, visit the NTSB Records Search website. NTSB# LAX96IA032