Aircraft Systems Integration Experience
New aircraft projects demand a higher level of integration and risk sharing by potential integrators. The system supplier should have a proven track record of performing all the required integration tasks to support a new or retrofit aircraft installation. Kidde Aerospace and Defense (KAD) has long been known as component suppliers, but is now a system integrator in its own right, and is the only fire protection supplier with all the necessary products and design disciplines to efficiently integrate such systems. This has been demonstrated on four new programs (DHC 8 400, Global Express, CRJ 700, Dornier 728 and F 22) wherein KAD is responsible for total system integration and certification of all the aircraft fire protection systems. The result is cost efficient systems with enhanced capabilities in terms of maintainability and low cost of ownership.
Aircraft Thermal Detection Terminal Lug Sensing Element (TLSE)
The TLSE is a notable development achievement, accomplished in concert with Boeing. A revolutionary design concept, the TLSE eliminated the necessity for electrical connectors, which have historically been a source of trouble in the harsh environment of aircraft engines. A closely monitored reliability tracking program conducted by KAD in conjunction with Boeing and airlines around the world generated the following data: From 1988 through January, 1996, 179,000,000 flight hours had accumulated for KAD TLSEs on Boeing 727, 737, 747, 767 and other aircraft. The TLSE experienced no false alarms and had an operating MeanTime Between Failure of 8,500,000 hours. To date, there have still been no confirmed false alarms attributable to the TLSE.
Thermal Detection Advanced Pneumatic Detectors (APD)
KAD's APDs are being offered to satisfy customers who prefer the pneumatic operating principle and/or are having problems with the design of existing pneumatic detectors in service.
The APD was initially developed by Aerosafe International (Richmond, California) by an engineering staff that had acquired a wealth of experience in pneumatic fire and overheat detection. The objective was to use their 100+ years of cumulative knowledge of metal hydrides and materials engineering experience to overcome the shortcomings of existing pneumatic detection technology. The APD is the successful result of that effort.
In 1995, KAD purchased the pneumatic detector product line from Aerosafe, and thus acquired the APD technology, manufacturing equipment and key personnel. APDs are now being produced at our North Carolina facility.
Many aircraft manufacturers and operators who use pneumatic detection are changing to the KAD APD in order to eliminate nuisance false alarms caused by exposure to the rigors of the aircraft engine environment. Still others are switching because, although they may not actually experience false alarms, the replacement rate for the older type of pneumatic detector is higher than desired (the failure mode is a dramatic change in pressure switch alarm set point, resulting in inability to meet original calibration requirements).
The APD was designed to eliminate the problems described above. After exhaustive laboratory testing to environments far in excess of those required by Federal Aviation Administration (FAA) TSO C11e, and subsequent good in service experience, the APD has become the standard by which pneumatic detectors are judged. All APDs are fully qualified to MIL F 7872C and meet FAA TSO C11e approval requirements.
Optical Flame Detection (OFD)
KAD's OFD utilizes the 4.3 micrometer (µ) infrared band to sense fires. Infrared energy generated by the excitation of CO2 molecules in a hydrocarbon fire impinges upon the sensor, which in turn produces a micro volt electrical signal. This signal is then amplified to a level that allows it to be processed. The KAD OFD utilizes digital signal processing circuitry to discriminate between the flicker from fire and background infrared sources such as a hot engine for engine compartment applications. It will also discriminate against non fire sources such as natural and manmade light.
An optional OFD design incorporates built in test (BIT) for complete detector functionality. This is accomplished by incorporating an infrared source within the sensor case. To initiate the BIT function, a 28 VDC signal is applied to the test input of the detector. At this point, the infrared source pulses heat to the sensor which in turn causes the detector to output an alarm signal.
The KAD 4.3µ OFD has been qualified to the requirements of MIL F 23447 and is FAA TSO C79 approved. This design protects the Sikorsky S 76, S 92, and the RAH 66 Comanche.
Smoke Detection/Fire Extinguishing Class D Cargo
The FAA has released its Notice of Proposed Rule Making (NPRM). The effective date for the final rule is January 1998; all affected airplanes must be in compliance by January 2001 (3 years).
The KAD team is proposing an off the shelf package, designed in conjunction with a major U.S. airline and with beneficial inputs from a number of airlines and aircraft manufacturers. This system is currently completing component qualification and system or STC certification on 727, 737, MD 80/DC 9 and L 1011 aircraft and full scale production will begin summer 1997. The system is modular and can be adapted for any aircraft type or configuration.
For our off the shelf Class D cargo fire protection system, KAD worked very closely with a major U.S. Airline to: 1) Identify the design requirements (e.g. reliability, dispatchability, compliance with FAA requirements, and ease of retrofit); 2) Define a complete aircraft Bill of Materials; 3) Perform testing to show compliance; and 4) Obtain the necessary approvals.
Design guidance was also sought from a number of other airlines and aircraft manufacturers. This process has taken approximately 9 months of effort by a very pro active KA design team working with our team member airline and an extremely responsive FAA Certification Office. KAD has already gone through the various design iterations, lessons learned and testing anomalies that have resulted in the system we are now fielding.
A typical KAD cargo fire protection retrofit kit consists of the following equipment:
- Dual Loop Photoelectric Smoke Detectors
- Cockpit Panel, Cargo Smoke Detection
- Cockpit Panel, Cargo Fire Extinguishing
- Cargo Electronics Unit
- Extinguisher, Fire Knock Down
- Extinguisher, Fire Inerting
- Cockpit Cargo Fire Annunciators
Aircraft Fire Extinguishing
KAD offers fire suppression hardware for protection against the full spectrum of aircraft fire hazard scenarios. The technology embraces single and multi outlet spherical, cylindrical or radial tubular containers for liquid extinguishing agents, manufactured from stainless steel or titanium. It also includes solid propellant based suppression devices and dedicated electronic modules for system monitoring and control. These systems can be configured for either crew commanded or automatic activation.
Examples of KAD suppression equipment:
- Engine/APU High Rate Discharge Containers
- Cargo/Combi Low Rate Discharge Containers
- Automatic Lavatory Extinguishers
- Specialized Dry Bay Suppression Units
- Long Life Hermetically Sealed Diagnostic Devices
- Suppression Support Equipment
- Filter/Dryer/Metering Devices
- Directional Control Hardware
- Discharge and Thermal Relief Indicators
Control / Interface Electronics
Various control/interface electronics interface with sensor assemblies and in some applications, extinguisher assemblies. Some of the key features that have been or are currently being utilized include:
- Fire detection monitoring circuitry; used on all KA
- Microprocessor based control electronics and logic; this technology is used on the C 17, MD 11, B 2, 777, Global Express, and the CRJ 700.
- Data bus communication systems. MIL STD 1553b data bus is designed into the C 17 and B 2 control systems. ARINC 429/629 type systems are designed into the MD11, 777, Global Express and CRJ 700 control electronic systems.
- AFOLTS/BIT architecture; one version of this technology is used by on the C 17 Fire Detection and Manifold Failure Detection Systems, and followed Boeing's 767 AFOLTS card design.
- Extensive Built In Test features with component (LRU) fault/event location features; used on the C 17 Manifold Failure Detection system, 777 fire and overheat detection systems, MD 95 overheat system and the F 22 overheat detection system.
- HIRF/EMI/Lightning hardening of electronic systems; the more sophisticated versions are utilized on the 777, C 17, Eurofighter, and the Bombardier Regional Jet.
- Micro/miniaturization of electronics; KA has successfully deployed the use of surface mount technology on our smoke and flame detector product lines.
Other Products RE covery A nd C onditioning for H alon (REACH™)
KAD carried out the design, development, and manufacture of the REACH ™ Halon Recycling Unit. This system is the first recovery approach capable of capturing Halon 1301 with greater than 98% efficiency and then conditioning it back to D5632 95, ASTM Type 11 standards.