27 de jan. de 2010

Helicopteros em Operações de Perseguição Policial -- Estudo Realizado pela Universidade da Carolina do Sul/EUA

Title: Helicopters in Pursuit Operations.
Series: Research in Action
Author: Geoffrey P. Alpert
Published: August 1998
Subject: Police equipment, vehicles
8 pages
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U.S. Department of Justice
Office of Justice Programs
National Institute of Justice
National Institute of Justice
Jeremy Travis, Director
Research in Action
August 1998
Helicopters in Pursuit Operations
Geoffrey P. Alpert
Advancements in helicopters and onboard auxiliary equipment have
improved the ability of police departments to fight crime and maintain
public safety. Helicopters assist police activities by providing support and
a presence in the air. They serve an important part in the advancement of
law enforcement strategies and tactics.
From their observational vantage point, the helicopter pilot or observer can
monitor a vehicle safely and provide pertinent information to ground
pursuit officers allowing them to:
o Remain in close proximity to the suspect while tracking the location and
direction without being noticed, enabling officers on the ground to take
action once the suspect has stopped or exited the vehicle.
o Assist with a call involving an officer in trouble by providing directions
and if necessary a show of force.
o Report on traffic or environmental conditions.
The versatility, range, and vantage point of the helicopter allows ground
officers to conduct pursuits more successfully, decreasing the use of
high-speed pursuits and increasing apprehension rates.
While existing information on the uses, costs, and effectiveness of
helicopters in police operations generally indicates that the helicopter can
play a valuable role, there has been no research that examined the uses and
productivity of the helicopter in pursuit operations. This research study
conducted for the National Institute of Justice addressed these issues.
This Research in Action presents findings and assessments from a study of
helicopters used in pursuit operations for the Baltimore City and
Miami-Dade County Police Departments.
The two study sites: Baltimore City and Miami-Dade County
The study focused on two geographically and demographically contrasting
sites that have been successfully using helicopters in pursuit activities.
Baltimore City is approximately 80 square miles in size and is laid out in
narrow streets. The city is densely populated, with roughly 750,000
people. The Baltimore Police Department is divided into nine police
districts and its helicopter unit is responsible for all areas of the city.
Miami-Dade County extends over approximately 2,000 square miles, with
a population of approximately 3 million people. The county covers a
variety of areas less densely populated than Baltimore City, including
rural, commercial, and residential neighborhoods.
The primary function of the Baltimore Police Department helicopter unit
is to perform routine patrol, at an altitude of 500 feet, and to respond to
calls for service. The observer in the helicopter can provide detailed
support information to ground units. The primary purpose of the
Miami-Dade Police helicopter unit is to respond to calls for service as well
as to provide a patrol function. Due to the spatial distribution of the two
jurisdictions, the helicopter's primary role in Baltimore is patrol, and
response in Miami-Dade. Both sites, however, place a high priority on
responding to calls for service from both the dispatcher and the ground
unit officers. As a result, both units play a crucial role during pursuits (see
"Helicopter Features").
Primary pursuit operations
The study looked at each site's policy for ground and helicopter pursuit
activity. Baltimore has a discouragement policy for vehicular pursuits and
Miami-Dade has a policy that only permits ground pursuits for violent
felonies. Once a ground unit initiates a traffic, investigative, or felony
stop, and the suspect refuses to pull over and begins to flee, the ground
units slow down and turn off all emergency equipment (unless the pursuit
is justified by policy) "to avoid pushing the fleeing vehicle."[1]
In most cases, unless a helicopter is available, the ground units terminate
their pursuit rather than pursue a fleeing suspect. When a helicopter is
available, the ground unit ceases its active pursuit, turns off its emergency
equipment, slows down, and continues to remain in the general area of the
suspect's vehicle. The ground unit officers rely on the helicopter crew to
transmit directions and other information to determine when to resume
pursuit activity. Both Miami-Dade's and Baltimore's ground units follow
at a safe distance so that the suspect is not aware of police presence.
In both departments, suspects are observed until they stop and exit the
vehicle, at which time ground units can move in and take the suspects into
custody. Exceptions to this practice are situations in which a suspect is
driving erratically, running through controlled intersections, or
endangering people. If any of these occur, the helicopter observer
(Baltimore) or pilot (Miami-Dade) may take the following action:
o Communicate to the ground units that the subject is accelerating fleeing
o Make the suspect aware of the helicopter's presence in hope that the
suspect will cease fleeing.
o Use the searchlight to illuminate the suspect's position during night
Neither department uses the onboard searchlight to blind a fleeing suspect
to force the individual to stop the vehicle, but maximizes on its capability
to illuminate the vehicle for the police, light an area to alert civilian
motorists of an oncoming danger, and light the roadway should the fleeing
suspect turn off the vehicle's lights. Both Baltimore's and Miami-Dade's
helicopters are equipped with a combination of crime-fighting tools--the
radio, searchlight, infrared heat sensing system, and camera--that together
are effective tactical resources available to police during patrol and
response activity.
Effectiveness in pursuits
The primary question considered as a result of the observations of these
units was the helicopter's effectiveness in pursuit activities. Available data
permitted some basic comparisons on the reasons for pursuits and their
effectiveness. Data were collected from Baltimore from July 1995 through
June 1996 and from Miami-Dade for the calendar year 1996.
Miami-Dade helicopters were involved in 43 pursuits (see Exhibit 1). In
Baltimore, helicopters were involved in 89 pursuits. These statistics
indicate that both departments have had a high arrest-success rate for using
helicopters in pursuits.
For both helicopter units, a stolen car was the most common reason for
initiating a pursuit. There were 21 pursuits involving a stolen car in
Miami-Dade and 38 in Baltimore. In addition, there were 10 pursuits for
armed robbery or robbery in Miami-Dade compared to 9 pursuits for
similar reasons in Baltimore (see Exhibit 2). The Baltimore helicopter unit
reported that the specific type of robbery involved carjacking in 7 out of
the 9 robbery pursuits. Almost 57 percent of the pursuits in Baltimore
occurred at night. Although information on exact times for most of the
pursuits in Miami-Dade was not available, the usable data did reveal that
approximately one-half of the helicopter pursuits were conducted at night.
The most common pursuit scenario involved a helicopter following a
vehicle from which one or more suspects had "bailed-out." There were
many "pursuits" that did not involve ground units until the suspect had
exited and fled from the vehicle once it had stopped. In both units, the data
indicated that when a helicopter became involved in a pursuit, the most
likely outcome was an arrest. Both Baltimore and Miami-Dade had
additional findings that are presented in Exhibits 3 and 4.
These data also compare favorably to the results of ground pursuits.
Agencies reported that approximately 75 percent of ground pursuits result
in an apprehension.[2] Law enforcement agencies have been aided by the
versatility, vision, and speed of helicopters.[3] Additionally, both agencies
in the study reported similarities in the reasons for their initial
involvement in a pursuit.
Case studies support helicopters in pursuits
In a sample of seven documented pursuit cases from the two sites, five
involved a stolen vehicle, and six resulted in bail-out of the suspect(s)
once ground units began to follow at a distance. The helicopter aerial
surveillance allowed the ground units to follow a suspect's vehicle at a safe
distance, and in most cases without the use of emergency equipment. In
addition, the helicopter units provided the ground officers with crucial
information, such as reporting whether or not suspects were carrying
weapons. The information provided to ground units from the helicopter
flight crews was very important to officer and public safety as well as to
the immediate arrest of many of the suspects in these pursuits.
The data presented in this report demonstrate that helicopters can provide
a valuable service to law enforcement in general and to the pursuit
function in particular. The helicopter can assist ground units as a platform
from which to observe, track, and illuminate people or places on the
ground. Specifically, the helicopter serves as backup to ground units.
Flight crews can provide a perspective that cannot be achieved on the
ground. They can communicate with ground units and provide information
to direct them toward an intended position or away from a dangerous one.
The helicopter's altitude and onboard equipment, particularly the
searchlight, create a tactical advantage for the police by providing them
with assistance and aerial cover.
From its vantage point, a helicopter can be removed from direct action
while its crew can observe what is taking place below. In pursuits,
helicopters can provide important assistance without being noticed. They
can track vehicles and alert ground units to the direction, location, and any
activities that are going on in their view. This critical function allows the
ground units to turn off emergency equipment and slow down to protect
public safety while maintaining visual contact with the fleeing vehicle.
This tactical advantage has proven to be very successful in the
apprehension of fleeing suspects and the reduction of risk to the public.
Additionally, a helicopter can, at determined times, make itself known to
the suspect as a show of authority and a show of force.
Although helicopters have proven to be a credible component of pursuits,
as their role increases, it will be important to develop policies guiding their
activities, including specific circumstances when a ground unit supervisor
authorizes his or her officers to continue ground pursuit.
As part of these policy determinations, use of the spotlight during pursuits
will require structured guidelines to maintain it as an important
crime-fighting tool. Guidelines need to be based on the spotlight's effect
on the fleeing suspect and environment, to ensure that it is used
effectively, for its intended and appropriate goal, in a manner that does not
encourage a suspect to take more risks or continue dangerous actions.
Since this study is the first on the use of helicopters in pursuit, it is not
surprising that the author found a lack of recordkeeping policy in agencies
to compile and analyze their own efforts. Similarly, the study of helicopter
pursuits follows the tradition of research on ground units in pursuit.
Tracking and analyzing ground pursuits is only a relatively recent
requirement in many police departments. The Miami-Dade Police
Department is a pioneer in this area and has been keeping detailed records
on ground pursuits since the 1980s.[4] Miami-Dade has also been
maintaining similar records for helicopter pursuits since mid-1996, but
many agencies in the country still do not require a specialized reporting
form for ground pursuits.[5] (See Exhibit 5.) Future analysis would benefit
from a change in reporting and recordkeeping procedures. Linking the
reports of both ground and air units would assist in understanding the
whole pursuit picture.
1. Interview. Womack, Doug, formerly Sergeant of the Baltimore
helicopter unit, July 14, 1994.
2. Alpert, Geoffrey, Dennis Kenney, Roger Dunham, William Smith and
Michael Cosgrove. Police Pursuit and the Use of Force, Final Report,
Washington, D.C.: U.S. Department of Justice, National Institute of
Justice, 1996, NCJ 164833.
3. McGowan, Robert. "Police Helicopters," Police Chief, (February
1978a):45:57-60, 81 and (March 1978b):45:56-59.
4. Alpert, Geoffrey and Roger Dunham. Police Pursuit Driving. New
York: Greenwood Press, 1990.
5. Kenney, Dennis and Geoffrey Alpert. "A National Survey of Pursuits
and the Use of Police Force: Data from Law Enforcement Agencies."
Journal of Criminal Justice, (1997): 25:315-323.
Selected Bibliography
Alpert, Geoffrey, Dennis Kenney, Roger Dunham, William Smith and
Michael Cosgrove. Police Pursuit and the Use of Force, Final Report,
Washington, D.C.: U.S. Department of Justice, National Institute of
Justice, 1996, NCJ 164833.
Alpert, Geoffrey and Roger Dunham. Police Pursuit Driving. New York:
Greenwood Press, 1990.
Bureau of Justice Statistics. Local Police Departments Survey. U.S.
Department of Justice, 1993.
Dade County Public Safety Department. Slow Take-off and Landing
Aircraft (STOL) Report. Dade County Public Safety Department, 1971.
Defoor, Ken."Houston Police Department's Eye in the Sky." FBI Law
Enforcement Bulletin, (1981):50:2-4.
Hoffman, Carl. "The Helicops."Air & Space, (November 1996):24-33.
Kenney, Dennis and Geoffrey Alpert. "A National Survey of Pursuits and
the Use of Police Force: Data from Law Enforcement Agencies." Journal
of Criminal Justice, (1997):25:315-323.
Kincaid, James. "Light Helicopters in a Police Role." Paper Presented at
the International Association of Police Aviation Units. Gatwick, England,
September 1995.
McGowan, Robert. "Police Helicopters," Police Chief, (February
1978a):45:57-60, 81.
McGowan, Robert. "Police Helicopters." Police Chief, (March
McGowan, Robert. "Police Helicopters." Police Chief, (April
McLean, Herbert, "Flight Operations," Law and Order, (July
Morris, Cole. "Helicopter Support." Law and Order, ( 1995):43:58, 65-66.
Morrison, Richard. "Getting Up in the Air: Starting an Aviation Unit."
Law and Order, (July 1994):42:60-63.
Pauley, Nicholas. "Pennsylvania State Police Aviation Division-Ten Years
Old." Law and Order, (September 1979):27:44-49.
Simonsen, Clifford. "Helicopter Patrol." Police Chief, (October,
Stone, Alfred & Stuart DeLuca. Police Administration: An Introduction.
New York: John Wiley & Sons, 1985.
Yates, Tom. "Eyes in the Sky." Law and Order, (July, 1994):42:65-69.
Helicopter Features
The Baltimore City helicopter unit was formed in November 1970. Since
its inception, the helicopter unit has used the same model Schweizer
300-C helicopter. According to the pilots in the unit, it is easy to
maneuver, has 360-degree visibility, and a relatively small rotor. These
features allow the helicopter unit to patrol in all parts of the city. The
Schweizer 300-C, however, is limited to 600 pounds and is therefore
restricted to two passengers (pilot and observer), whose total weight
cannot exceed 380 pounds.
The Miami-Dade aviation unit was established in 1959 as the Sheriff's Air
Patrol. Currently, the aviation unit owns four Jet Long Ranger Helicopters
(B206L-4). The Rangers are considerably larger than the Schweizer
300-C, holding up to seven people and equipment. The Miami-Dade Unit
flies a helicopter larger than the Schweizer 300-C because they perform a
variety of functions, including transportation and disaster assistance.
The helicopters used in both units are equipped with support equipment
and crime-fighting tools that assist the officers with their mission as a
patrol or response vehicle. The Baltimore Schweizers have VHF
transceivers with which the pilot communicates with Air Traffic Control
(ATC). They are also equipped with a siren, public address system, police
radios, searchlight, and an infrared heat sensing system. The Miami-Dade
Jet Rangers also have VHF transceivers, a public address system, police
radios, searchlight, and an infrared heat sensing system.
Dr. Geoffrey P. Alpert is Professor of Criminology at the College of
Criminal Justice, the University of South Carolina. Dr. Alpert has
conducted research on police pursuits and police use of force for more
than 15 years.
This study was performed under NIJ grant 93-IJ-CX-0061, awarded to the
University of South Carolina. Points of view in this document are those of
the author and do not necessarily reflect the official position or policies of
the U.S. Department of Justice.
The National Institute of Justice is a component of the Office of Justice
Programs, which also includes the Bureau of Justice Assistance, the
Bureau of Justice Statistics, the Office of Juvenile Justice and Delinquency
Prevention, and the Office for Victims of Crime.
NCJ 171695

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