After more than ten years of research, development, and certification effort, a team of highly-experienced autopilot professionals is now manufacturing and marketing the first professional, full-function, digital flight control system that is both lightweight and affordable for the light- and medium-sized helicopter fleet. No longer is system pricing beyond the cost-effective reach of this vital portion of the rotorcraft market.

All helicopter pilots now have available to them the safety enhancements and multiple flight benefits of the stability augmentation and autopilot systems utilized by pilots of the larger helicopters and virtually all fixed-wing aircraft for decades.

Cool City Avionics’ automatic flight control systems (autopilots) and stability augmentation systems (SAS and SCAS) offer the pilot the ability to more easily manage flights, while providing the passengers a more comfortable ride. SAS and autopilot systems are proven aids for reducing pilot stress and fatigue, reducing pilot workload and providing the pilot time to more easily perform flight-related tasks, all while providing an enhanced safety environment for everyone on board.

And, significantly, these are the first, and only, autopilots to be approved under the new FAA TSO-C198 and RTCA DO-325 MOPS.

The autopilot (AP) Controller is used to select subsystem functions and autopilot modes. It also is used to display function and mode annunciations and warnings via the LED lighting. The AP Controller is NVIS compatible for operations using night-vision equipment.

Small in size, the controller measures only 6¼” W X 1” H X ¾” D and it may be installed in a single or dual controller configuration without modification to the system.

The following subsystem functions are selectable from the controller:

¦AP¦ Autopilot (ON-OFF) – When AP “ON” selected, AP comes on in attitude retention mode in pitch and roll axes and “ATT” will be annunciated under HDG button
¦YD¦ Yaw Damper (ON-OFF) – Engages with AP ON – YD may be operated independently, with AP and/or with SCAS
¦FT¦ Force Trim (ON-OFF) –Only selectable when AP is ”OFF” – may be operated with SCAS and/or YD/or independently.
¦SCAS¦ SCAS (OFF-ON) – Defaults to ON at aircraft system power up – May be operated independently – Independent operation requires hands on cyclic at all time

The following autopilot modes are selectable from the controller:

¦HDG¦ Heading – follows heading bug from DG/HSI
¦IAS¦ Indicated Airspeed – samples and maintains current airspeed at engagement
¦ALT¦ Altitude Hold – samples and maintains current altitude at engagement Glide slope is armed when selected while in Alt mode if tracking the localizer GS annunciation is located under ALT button
¦VS¦ Vertical Speed – samples and maintains current vertical speed at engagement
¦LNAV¦ Lateral Navigation – senses selected navigation source such as VOR, LOC, GPSS, and Back Course Back Course (B/C) annunciation is located below LNAV button
¦VNAV¦ Vertical Navigation – mode used for WAAS GPS LPV approach

The Cool City digital flight guidance computer (DFGC) is the heart and soul of the automatic flight control system. The DFGC contains the latest in electronics technology with surface-mount printed circuit boards (PCBs), solid-state sensors, accelerometers and air transducers. Cool City uses the latest in surface-mount technology and electronic hardware to provide high reliability and RF interference resistance.

Cool City makes use of a single chassis for the electronics of the system. Each box is configured for the system to be installed; however, should you choose to update the system later, it is accomplished by the addition of the requisite internal PCBs.
Although all system PCBs are located within this one box, the autopilot and SCAS are independent and each has their own power source and internal power supply. The DFGC is tray-mounted outside the cockpit; therefore, installation in the cabin area has a very small footprint.

The tray for the DFGC contains a configuration module to store all airframe related specifics, which are downloaded by the DFGC each time at start-up. By utilizing this method, the DFGC remains generic with regards to different airframes. This allows operators of multiple helicopters to keep a single DFGC spare that may be used in many different airframe models with the same system installed. The tray also contains the air transducers; therefore, removing and replacing the DFGC does not require entry into the pitot-static system.

The DFGC contains 3-axis orthogonal, solid-state rate sensors, as well as an integral yaw-axis rate sensor and a long-term slip-skid sensor. The DFGC will interface with essentially all attitude systems for attitude data, ADAHRS from electronic flight instrument systems, AHRS, and/or the air data computer that have autopilot outputs.

Any failure of external data used by the autopilot causes the DFGC to revert to the internal rate package so you do not lose autopilot functions. This reversion occurs seamlessly; however, it is annunciated on the AP Controller by the annunciation of RATE.
The DFGC has seven ‘receive’ and one ‘transmit’ ARINC 429 ports, a CAN bus port and analog interfaces for connecting to the aircraft systems. The DFGC also contains a digital data recorder function which records up to 48 channels of information in a 28-minute loop.

Additionally, the computer contains a bi-directional CAN port for diagnostics that can be used with an external recorder for continuous recording of operations for Flight Operations Quality Assurance (FOQA).

The DFGC has been tested to the latest DO-160 environmental qualifications, against HIRF and protected against lightning, to ensure it meets the standards established by Cool City and the FAA and, more importantly, the expectations of you…the customer.

To differentiate between autopilot / stability augmentation system components, Cool City uses the nomenclature of actuator for the series electromechanical devices used in the SAS/SCAS systems. The electromechanical devices of the autopilot system are referred to as parallel servos; however, in general, the terms actuator and servo are interchangeable.

Cool City manufactures two models of series actuators, a linear and a rotary series actuator. As implied in the name, the linear actuators move in and out and are installed in push-pull control tubes. The rotary actuators are used in control systems incorporating a torque tube that rotates for control travel.

The series actuator is manufactured on CNC machinery from 6061 billet aluminum for strength and corrosion protected per MIL-DTL-5541. Cool City uses a commercial, size 17 stepper motor to drive the actuator. Also, key to the structural integrity of the Cool City actuator is the dovetail mechanical joint that holds the actuator housing and the electronics box together without depending upon fasteners for strength.

The Cool City actuators are fast-action units with very limited control travel authority. In most instances, the actuators operate full travel in less than a second and have approximately 10% control travel authority. The actuators have a very high duty cycle when operating in turbulence. When quiescent or at system shut-down, the actuators automatically re-center.

The series actuator provides SAS/SCAS actions in a short, but fast motion. Mounted in the main flight control tubes, these actuators have very limited travel authority, usually less than 10 percent of full control travel. While limited in travel distance, these actuators operate at a high rate of speed. Full travel for the actuator occurs in less than one second.

For safety purposes, the actuators have an internal electrical and mechanical stop. The mechanical stop is located just beyond the electrical stop and is not reached in normal operation. Other than the obvious improvements in the aircraft stability, operation of the actuators is transparent to the pilot.

To differentiate between autopilot / stability augmentation system components, Cool City uses the nomenclature of actuator for the series electromechanical devices used in the SAS/SCAS systems. The electromechanical devices of the autopilot system are referred to as parallel servos; however, in general, the terms actuator and servo are interchangeable.

Cool City manufactures two models of series actuators, a linear and a rotary series actuator. As implied in the name, the linear actuators move in and out and are installed in push-pull control tubes. The rotary actuators are used in control systems incorporating a torque tube that rotates for control travel.

The series actuator is manufactured on CNC machinery from 6061 billet aluminum for strength and corrosion protected per MIL-DTL-5541. Cool City uses a commercial, size 17 stepper motor to drive the actuator. Also, key to the structural integrity of the Cool City actuator is the dovetail mechanical joint that holds the actuator housing and the electronics box together without depending upon fasteners for strength.

The Cool City actuators are fast-action units with very limited control travel authority. In most instances, the actuators operate full travel in less than a second and have approximately 10% control travel authority. The actuators have a very high duty cycle when operating in turbulence. When quiescent or at system shut-down, the actuators automatically re-center.

The series actuator provides SAS/SCAS actions in a short, but fast motion. Mounted in the main flight control tubes, these actuators have very limited travel authority, usually less than 10 percent of full control travel. While limited in travel distance, these actuators operate at a high rate of speed. Full travel for the actuator occurs in less than one second.

For safety purposes, the actuators have an internal electrical and mechanical stop. The mechanical stop is located just beyond the electrical stop and is not reached in normal operation. Other than the obvious improvements in the aircraft stability, operation of the actuators is transparent to the pilot.

To differentiate between autopilot and stability augmentation system components, Cool City uses the nomenclature of servo for the parallel-installed, electromechanical devices used in the autopilot systems. The series-installed, electromechanical devices of the SAS/SCAS are referred to as actuators; however, in general, the terms actuator and servo are interchangeable.

The parallel servo is considered the most critical element in the autopilot system because it is the only component attached to the flight controls. Therefore, the servo capstan incorporates an internal spring mechanism and has an internal gradient that may be overridden in the case of a servo failure or the pilot’s need to “fly through” the autopilot.

The servo capstan gradient requires increasing force as you move the cyclic from the original override point. Upon releasing the cyclic, the spring mechanism will return the cyclic to the original position.

The autopilot servo is manufactured on CNC machinery from 6061 billet aluminum for strength and corrosion protected per MIL-DTL-5541. For long life and smoothness of operation, the capstan rides on straddle-mounted roller bearings. Additionally, all servo gearing and shafts are manufactured from stainless steel and the shafts run on ball or roller bearings as well.
Cool City uses a commercial, size 17 stepper motor to drive the servo. Stepper motors are not subject to “starting voltage” problems so prevalent in older systems. Also, from a safety standpoint, there is no single-point failure that can cause the stepper motor to have a “runaway”.

The parallel servo is used in roll, pitch, and may be optionally installed in the yaw axis of rotorcraft installations. The servo is connected to the aircraft’s primary control system through the use of either push-pull rods or bridle cables, dependent upon the specific requirements of the installation.

In addition to the attributes listed above, consider these additional features:

  • “Smart” servo design with precision servo position feedback
  • Servo engage-disengage mechanism tested to 500 in. lbs
  • Machined mating surfaces prevent internal contamination from external sources
  • 90° electrical connector for installation in confined areas

As with all autopilot systems, the servo is most critical to optimum autopilot performance and system longevity. Cool City has successfully subjected our servo to the most strenuous of environmental testing. We have also life-tested our servo over a half-million cycles without failure. We believe our servo is the most robust servo available on the market.

Mineral Wells, Texas – May 21, 2010 – Cool City Electronics, Inc. (CCE) announces that the Federal Aviation Administration (FAA) has informed the company of the issuance of the FAA Technical Standard Order Authorization (TSOA) for the CCE Stability Augmentation System (SAS), which consists of the SAS Computer with solid state gyros, as well as a Series Linear Actuator and a Series Rotary Actuator, both mounted in the flight control system in series with the pilot.

Cool City Avionics will be marketing this new system to the rotorcraft market, initially for the Robinson model R-44II helicopter. The SAS-100 is a stability augmentation system that improves the helicopter’s basic rate damping in turbulence by reducing the affect of high-rate upsets.

This approval by the FAA authorizes CCE to manufacture the SAS systems, however they cannot be installed in an aircraft until CCE receives further FAA approval in the form of a Supplemental Type Certificate (STC). CCE is currently in the process of securing the SAS STC for the Robinson R-44II helicopter, which is expected in the fourth quarter of 2010.

The SAS-100 system is the first CCE product to receive FAA certification. It offers roll and pitch stabilization that improves the handling qualities of a helicopter, while being transparent to the pilot.

“The receipt of the FAA TSOA for the SAS is a significant milestone in our product development program, said Jim Irwin, president and CEO. The SAS-100 is a relatively low cost way to make a small helicopter handle like a larger helicopter with more precision. We look forward to receiving the STC and beginning production of the SAS-100 systems late this year.”

Mineral Wells, Texas – May 17, 2010 – Cool City Electronics, Inc. (CCE) announces that the Federal Aviation Administration (FAA) has informed the company of the approval of their Quality Control Manual and inspection system. This approval by the FAA paves the way for issuance of the Technical Standard Order Authorization (TSOA) by the FAA for the Stability Augmentation System (SAS) components designed and built by CCE for marketing by Cool City Avionics. CCE expects FAA issuance of the TSOA within a few days.

The SAS-100 system will be the first CCE product to receive FAA certification. It offers roll and pitch stabilization that improves the handling qualities of a helicopter, while being transparent to the pilot.

The SAS-100 consists of a flight control computer with solid state gyros and roll and pitch actuators installed in the flight control system in series with the pilot.

“The FAA approval of our Quality Control Manual and inspection system is good news for Cool City, said Jim Irwin, president and CEO. We look forward to receiving the TSOA for the SAS shortly.”