March - April 2004
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Fixed-Wing Flight Ops: Then & Now
Does Your Mission Profile Include
Rotary & Fixed:
**Surveying The Skies:
FIXED WING OPS: Then & Now
by Mark A. Forror
Although some law enforcement agencies were flying search-and-rescue (SAR) missions well before the end of World War II, the oldest aviation units in law enforcement generally can trace their histories back to the late 1940s.
America’s post-war love affair with the automobile meant that patrol cars were no longer enough to stay a step ahead of drivers on the nation’s highways. By 1949, with the helicopter still in its infancy, the speed and range of fixed-wing aircraft made the airplane ideal for patrolling long stretches of highway.
New York State Police
The Aviation Unit of the New York State Police was one of the first law enforcement agencies to use aircraft to patrol the ground. In 1939, NYSP operated a Fleet biplane as a flying club airplane that was sometimes pressed into service to search for escaped criminals. However, the club aircraft was never regarded as an official division of the state police.
The real origin of the NYSP Aviation Unit can be traced back to the 1960s. We’ve had airplanes officially since1968, and it started almost exclusively in aerial speed enforcement on the New York Throughway says Capt. Ken Rogers, the unit’s chief pilot. At first we were flying daytime VFR with a Cessna 172. Now we’re flying King Airs with sophisticated avionics and de-icing equipment.
The NYSP currently operates six fixed-wing aircraft: a Partenavia P68, a Beech King Air 350 and B200, two Cessna 206Us, and a 1967 Cessna 172H. The 172H, which is the original aircraft that started the NYSP’s Aviation Unit, has a high-performance, constant-speed propeller and a Lycoming O-360 engine. Average annual flight time on the airplanes is about 1,800 hours.
The unit has 33 pilots, with paramedics or other pilots serving as observers. The division operates 13 helicopters in addition to the six fixed-wing aircraft. Airplanes currently perform such missions as spotting forest fires upstate, executive transport, some speed enforcement, prisoner transport, and transportation of organ transplant teams to hospitals.
The fixed-wing fleet carries infrared cameras, GPS navigation, radar altimeter, scalable radios, multifunction displays, weather radar, horizontal situation indicator (HSI), TCAS, autopilot and IFR avionics suite.
Since the terrorist attacks in New York in 2001, the department has been stepping up its long-term surveillance of harbors and other areas that may be vulnerable to future attack.
Mainly we use helicopters for that, but we have used fixed-wing aircraft on occasion," Rogers says. "Every time they’ve raised alert levels, we’ve gone on active patrols, particularly in the southern part of the state.
Some of the areas targeted for heightened surveillance include railroad yards, bridges, reservoirs, airports, and power plants. The advantage of the fixed-wing aircraft over the helicopter is its endurance and fuel efficiency, which makes long surveillance missions more cost-effective, he says.
In 1949, the same year that the Nevada Highway Patrol was formed, the Texas Department of Public Safety (DPS) started with a single Navion airplane piloted by Max Westerman. A patrolman for DPS License and Weight Service, Westerman was transferred to the Texas Rangers before becoming the service’s first pilot.
By January 1953, the airplane, based in Austin, was so much in demand that the DPS added a second pilot. From 1953 to September 1967, the Texas DPS Aircraft Section remained a two-pilot operation, though the fixed-wing fleet was upgraded to two twin-engine Cessna 310s and a Lockheed Lodestar. DPS also purchased a twin-engine Cessna 320 and stationed it in Midland, Texas. In 1968, DPS lease- purchased its first helicopter, a Bell 47G.
During the 1970s and into the 1980s, DPS operated a number of different Cessna twins and single-engine aircraft. These included several models in the Cessna 400 series, single-engine 210s and 206s and even a military surplus Cessna T-41. Today, the agency’s fixed-wing fleet consists of three 210s, four 206s, and one twin-engine Turbo Commander 1000—a drug seizure aircraft acquired in the late 1980s.
The unit’s basic mission has changed from predominantly highway patrol and transport to narcotics enforcement. In 1984, DPS acquired another aircraft, a Cessna 210, which also was seized in anti-narcotics operations.
Most of the aircraft we seized were sold at auction and the proceeds went to new equipment for officers and other equipment used to help fight the war on drugs, says Pilot/Sgt. Tim Middleton.
The money is pooled in a Seized Funds account, from which various departments are allowed to draw. That money helps fund current operations, which includes criminal surveillance, traffic enforcement (spotting aggressive drivers, etc.), criminal investigations, transportation of personnel and equipment, prisoner transport, and SAR.
Nevada Highway Patrol
A division of the Nevada DPS, the Nevada Highway Patrol’s aircraft unit began in 1984 as a federally funded program dedicated exclusively to enforcing the federally mandated 55 mile-per-hour speed limit. A result of the Arab oil embargoes, the national speed limit was a fuel-saving measure imposed on all interstate and federal highways in 1974. The task of ensuring the state’s compliance with the federal law fell on the Nevada Highway Patrol. The law required 50 percent of the state’s drivers to regularly obey the new speed limit.
"In Nevada back then we had a problem with our 50 percent compliance rate," says Pilot Sgt. Pete Onorato, the NHP’s senior pilot. Enforcement was necessary so we wouldn’t lose our federal highway funding. We provided the manpower and covered the personnel costs, and the feds provided the aircraft and maintenance."
At first the unit operated a Cessna 172RG, but added a 182RG two years later. The speed-enforcement mission quickly ran headlong into regional issues. In the state’s wide-open rural areas, the 55 mph limit was the first time Nevada highways ever had a speed restriction, and enforcement officers had trouble keeping up with violators.
As recently as last year, the NHP flew 135 speed enforcement missions resulting in 4,644 citations. Although that money does not go to the NHP directly, Onorato says, it still benefits the aviation unit indirectly by freeing up state funds for law enforcement programs.
When the federal government lifted the speed restriction in 1993, it stopped funding the aviation unit, but transferred the airplane titles to the NHP on the condition that the airplanes would continue to be used for law enforcement purposes.
Today, the NHP has added a few new missions, but the unit’s basic tasking remains largely unchanged. The two principal missions are now speed enforcement and prisoner transport. How the NHP apportions its assets to each mission varies greatly by region. In Reno, about 80 percent of the missions are dedicated to speed enforcement, and 20 percent to prisoner transport. In Las Vegas, however, that ratio is flipped, with 80 percent of the missions going to prisoner transport and out-of-state extraditions. Statewide, the mix is about 60/40 in favor of speed enforcement missions.
Prisoner transports have benefited the most from fixed-wing operations. In the past, a prisoner from the eastern part of the state who was wanted on a warrant in Reno would have to be transported 400 miles by car. Prisoners were handed off from trooper to trooper as the prisoner crossed patrol divisions. With airplanes, the transport process is far less complicated, and prisoners have fewer opportunities for escape. In the past 12 months, the
NHP transported 84 prisoners statewide.
Other missions include assistance in ground pursuits, SAR, and "blood runs", or the transport of whole blood and plasma to hospitals for the benefit of critically injured patients.
The NHP’s aircraft unit continues to operate the same aircraft it started with, though the aviation division is studying the possibility of acquiring a new Cessna 206 in the near future.
Santa Barbara Sheriff’s Department
The Santa Barbara Sheriff’s Department is a relatively young operation. The aviation unit was formed in December 1996 with a Cessna 172RG seized from a narcotics bust and two military surplus OH-58 helicopters.
"The fixed-wing aircraft was mostly for patrol as a backup for the helicopters, says Deputy Dave Wight, acting chief pilot. We did some surveillance with it and we did some administrative transport with it, but it was mainly a backup for our helicopters. In February, the unit acquired a surplus UH-1 helicopter, but the Sheriff has not yet determined what its mission will be.
When the aviation unit was organized, Sheriff Jim Anderson was a private pilot, so he used the Cessna to travel to the capital in Sacramento for meetings with state officials. Since then, the Sheriff has replaced the 172RG with a Cessna 206H. The 206H is used for ground patrol support, SAR, VIP transport, surveillance and photographic missions.
However, the aircraft’ primary mission remains transport. The airplane is now available to any county government supervisor who requests it. Some county government officials who have used the airplane in the past include probation officers, fire department officers and planning commissioners.
Most missions are flown IFR. Both pilots and TFOs must have a minimum of 18 months field experience to be accepted into the training program. As a prerequisite for assignment to the unit, pilots must be instrument rated.
Wight says the Sheriff’s Department has considered acquiring a larger aircraft to be used exclusively for the transport of officials. Both the Sheriff and the Santa Barbara County Board of Supervisors have expressed interest in buying a Cessna Caravan or Raytheon King Air. However, recent operations and budgetary considerations have put that plan on hold for now, Wight says.
Lee County Sheriff’s Office
Two years ago, the Lee County Sheriff’s Office was an all-helicopter operation. In January 2004, the Aviation Unit flew more total hours aboard its fixed-wing airplanes, though it still operates one MD 500 and one OH-6 helicopter. The unit has learned that low-and-slow high-wing aircraft, such as the Maule, actually make better surveillance platforms than most helicopters.
"For surveillance, the fixed-wing aircraft is unmatched," says Chief Pilot Robert Roper. "It’s not going to replace the helicopter, but we’re getting more hours over the county, and that allows us to spend more time in the air without adversely affecting our budget. For the cost of one hour in the helicopter, we can fly ten hours in the Maule. We’re actually looking at expanding our personnel because of the lower cost."
In addition to its MD 500 and OH-6 helicopters, the sheriff operates three fixed-wing aircraft: two Maule single-engine airplanes, an M-5-180C and an MX-7-180A and a twin-engine Cessna 337 Skymaster. The fleet is based at Buckingham Airfield in Lehigh Acres, Florida, about five miles from Fort Myers.
"The early missions were primarily narcotics surveillance," Roper says. "We had such good success with the Maule that we started thinking about putting a FLIR on it." Today, the Lee County Sheriff’s Office uses a FLIR 7500 that goes back and forth between the two aircraft. Maule will display the Sheriff’s MX-7-180 equipped with a new FLIR 8500FW on the floor at this year’s APSA conference in Charlotte, North Carolina.
Lee County operates a FLIR 7500 with laser illuminator. The future goal, Roper says, is to have canine officers equipped with night-vision goggles (NVGs) on the ground, so that the
airplane can "paint" the suspect with the laser illuminator and direct ground
officers to the suspect at night.
"Right now, we fly predominantly during the day, but we want to expand to nighttime operations, so that we can assign TFOs full time," Roper says.
Although helicopters have come to dominate police aviation during the past couple of decades, there are still some missions that fixed-wing aircraft can do better or more cost-effectively than rotorcraft. Where range, endurance, platform stability, or maintenance and fuel costs are important issues, the fixed-wing aircraft will continue to occupy small but useful operational niches in airborne law enforcement.
Does Your Mission Profile Include Flying Low & Slow?
Learn why this flight regime can turn unexpectedly deadly.
by Mike Smotherman, FCI Training
During a recent nighttime flight in instrument meteorological conditions (IMC), a pilot flew a GPS runway 35, circle-to-land runway 17 approach, not realizing that something was terribly wrong. /p>
A witness reported that the airplane's downwind leg was two to three times closer to the runway than normal. The airplane’s turn radius to final approach was also much smaller than normal and the turn was relatively flat. The airplane appeared to be traveling at a relatively slow airspeed during the approach, and engine RPM didn’t increase during the turn. As the airplane turned toward final approach, the witness said its attitude instantaneously changed from relatively wings level to wings vertical. The aircraft stalled and stuck the ground short of the runway.
Examination of the wreckage confirmed this. The airplane impacted the ground almost vertically and, upon impact, was facing the opposite direction of the landing runway. Weather at the time included winds from 080 degrees true at six knots, visibility 2.5 miles in mist, an overcast ceiling at 300 feet AGL, and a temperature and dewpoint of 32 degrees Fahrenheit. No pre-impact mechanical malfunctions were found. The National Transportation Safety Board (NTSB) determined the probable cause of the stall/spin was the pilot’s failure to maintain adequate airspeed during the turn to final approach. Contributing factors included low ceilings and night lighting conditions.
The above scenario describes a low, tight traffic pattern in adverse weather conditions, but these conditions are not unusual for many law enforcement pilots observing targets. The temptation is great for pilots to slip into a skid to make the corner, but it can be extremely dangerous under the right conditions.
If you were on your game, had sufficient airspeed, didn’t encounter any wind shear and had luck on your side, you probably wouldn’t even know you were pushing the envelope. But the above accident illustrates just how deadly this situation can be if you’re not completely aware of your situation.
Stepping on The Ball
The NTSB’s probable cause of _failure to maintain adequate airspeed, while technically accurate, may not be very helpful to other pilots. Since the witness observed that the pilot of the accident aircraft did not use a steep bank angle to tighten his final turn, it’s a virtual certainty that he attempted a skidding turn using bottom rudder to _make the corner. Let’s look a little closer at the aerodynamic ramifications of using uncoordinated turns.
In coordinated flight, the relative wind meets a straight wing at 90 degrees as seen in diagram 1. Wing designers control stall characteristics by varying dihedral, wing twist, and so on. The stall will occur perpendicular to the relative wind, assuming a straight and symmetrical wing.
As we all learned in ground school, most straight-winged aircraft are designed to stall at the wing root, which benefits the pilot in two ways. First, the onset of the stall at the wing root provides an aerodynamic stall warning as the turbulent air hits the elevator. Second, during this approach-to-stall, the wingtips are relatively unaffected, so that the ailerons will remain somewhat effective. But what happens to our straight-wing airplane if we introduce a slip or skid by using the rudder? Do the stall characteristics change? To answer this question, we must first look at the stall characteristics of a swept wing.
Where does a swept wing stall? At the tip of the wing, because the stall generally occurs perpendicular to the relative wind as shown in digram 2. But how does this affect what we feel in the cockpit? Since the approach-to-stall starts at the tip, there will be no turbulent airflow over the elevator, hence no warning on the yoke or stick. This is why most high-performance jets will install an artificial stall warning system called a _stick shaker._ This system is basically a vibrator attached to the yoke that activates based on approach-to-stall Angle of Attack (AOA). You also lose aileron authority since the stall is beginning out on the wing tips near the ailerons.
As we yaw our straight-winged aircraft, we cause the wing to sweep back with respect to the relative wind, as you can see in the diagram.
What is normally a straight wing in coordinated flight has now taken on the characteristics of a swept wing. Since the wing tip stalls first, you will not get the normal approach-to-stall buffet on your elevator, and you will lose aileron effectiveness at the onset of a stall. The forward (right) wing in the above diagram will not stall at the same time as the aft (left) wing, causing a rolling moment to the left.
To get to the bottom of this situation for a straight-wing airplane, we first have to look at the effects of roll and AOA on the lift characteristics of an unstalled wing in normal flight.
How does a rolling moment affect AOA on the wings of an aircraft in normal flight? Diagram 4 above shows that with a left roll, the left wing is pushed down into the relative wind, effectively increasing the AOA on that wing. The right wing moves away from the relative wind, effectively decreasing the AOA on the right wing. Since we are in normal flight, increased AOA means more lift (see the lift/drag chart in Diagram 5), and thus the left roll stops due to the increased lift as soon as we remove the cause of the roll by bringing the ailerons neutral. The aerodynamic principle involved here is _positive roll damping,_ where a roll or yaw input is positively dampened back to stable flight.
Negative Roll Damping
But what happens when a rolling moment is induced during stalled flight? Diagram 5 again shows that with a left roll, the left wing is pushed down into the relative wind and increases the AOA on that wing. The right wing moves away from the relative wind, decreasing the AOA on the right wing.
In stalled flight, increased AOA means less lift, and thus, the left rolling moment will continue due to the decreased lift and will continue to roll even if the input that caused the roll is removed. The problem is that the uneven lift is now caused by the differential in AOA on the stalled side of the lift/drag curve. This is known as negative roll damping, since the roll will not be dampened out.
Now, let’s apply this concept to our mishap analysis.
According to the accident report, the aircraft was in a left turn to final. As the pilot slipped into a skid using left rudder to make the tight turn, the receding wing on the left probably stalled while the advancing wing was still flying.
Now enter negative roll damping. The uneven lift due to negative roll damping caused a rapid rolling moment to the left, in the direction of the applied rudder. Once the roll started, it continued despite removal of the left rudder input that caused the roll because the ailerons were no longer effective.
The quickest way for the pilot to correct this left rolling moment would be to push directly forward on the yoke, which decreases the AOA. The decreased AOA puts the aircraft below stalled AOA and back into normal flight, immediately stopping the roll because of positive roll damping. The pilot could then roll the aircraft back to level flight with the ailerons and recover from the dive, altitude permitting.
If you’ve never experienced an uncoordinated stall, you should definitely practice these with an instructor who has expertise in this area. It could save your life and aircraft.
Mike Smotherman is director of flight training and a check pilot at FCI Training, Mesa, Arizona. He also is an air combat and EMT trainer.
Rotary & Fixed
It is the challenge of law enforcement today
to make sure needs are met with
competence and confidence.
by Nat McClain, Sr.
Chief Pilotbr> Jacksonville (FL) Sheriff’s Office
As a 32-year veteran of law enforcement with 20 of those years in law enforcement aviation, I have experienced the expansion of aviation from an observation platform of reciprocating helicopters and small fixed-wing airplanes to tactical operations with turbine helicopters and mid-sized turbo-props and jets.
The potential for effective aviation operations has existed since the Wright Brothers. However, implementation is a matter of public awareness and operation skills. It is the challenge of law enforcement today to make sure that both needs are met with competence and confidence.
For most Sheriff’s offices, there is a public requirement to provide expeditious transportation of personnel, fugitives and convicts across the nation. Whether this task is performed by commercial or private means, it becomes the mission of those that are planning for the future of the aviation fixed-wing operation. Expense is always the bottom line, however, the administrator has to take into consideration the cost of safety, convenience, and control of the situations that dictate our overall effectiveness.
For those of us who have been in the business of fixed-wing flight operations for any length of time, there has been a reconciliation of needs met by the cost of owning, maintaining and operating fixed-wing aircraft. For some, a small single-engine aircraft will adequately supplement their transportation needs. For others, there is an apparent need to deploy larger multi-engine aircraft with the capability of negotiating changing weather conditions over greater distances and faster speeds.
I once heard and remembered the following axiom, Only a well designed aircraft, properly maintained, and flown by a competent pilot is acceptably safe. This equates to a unit’s need to understand the mission and to be willing to meet those needs by appropriately equipping and staffing its aviation unit. The Jacksonville Sheriff’s Office in Florida has grown from small fixed-wing aircraft to larger twin-engine aircraft. The largest at this time is the C-12 (King-Air B200). Each aircraft not only brought to our unit unique flight abilities, but also unique skill requirements.
In 1979, regretfully we lost three officers due to a mission mishap in the crash of our Cessna 411. The response to that incident by our department was a categorical disapproval of twin-engine aircraft. It was not until March of 1993 that Chief John Rutherford (now Sheriff) initiated the move to reinstate the use of multi-engine aircraft, thereby increasing flight operations and capabilities commensurate to the overall transportation needs of our community.
Departments that properly access their mission will equip themselves with the appropriate aircraft, considering the maintenance and operational skills required to operate safely and efficiently. The administrator needs to be able to move on a moment’s notice with little or no restrictions. Most flights can and will be conducted with few layovers. However, when there is a layover, the flight moves on the following day at the discretion of the administrator.
Owning and operating aircraft versus contracting personnel for prisoner transportation has enabled our department to move more appropriately and cost effectively. Prisoners who are transported by law enforcement aircraft are more secure and pose much less threat to society.
Complex aircraft are not designed to be expensive; they are expensive because they are complex. However, complexity to the aviation community means safety due to more redundant and reliable systems. Keeping the homeland secure is a task that partly depends on efficient up-to-date aviation operations. Pro-active planning and implementation is critical to the overall outcome of efficient public safety. I believe the appropriate use of fixed-wing aircraft will ensure that outcome.