Communications ...sometimes referred to by the acronym ACARS (aircraft communications addressing and reporting system), which actually describes it well ...its purpose to communicate air to ground via predominantly three methods, vhf, satcom or hf, the data from the onboard flight management system or on-board maintenance computer.
Aircraft management systems... Monitoring the continued health of aircraft subsystems and identifying problems before they affect airworthiness has been a long-term goal of both the U.S. military and commercial aviation industry. Now, that goal has come closer to being realized with the ARINC Aircraft Condition Analysis and Management System (ACAMS), an aircraft diagnosis and prognosis system. ACAMS is unique in the industry because it offers real-time diagnosis and prognosis that accounts for subsystem or component interactions within a complex system.
ACAMS consists of onboard and ground-based elements. The onboard system collects information from numerous data sources. Proprietary ACAMS models and algorithms continually analyze these data in real time to identify and help manage anomalies that could adversely affect continued airworthiness. In certain cases, ACAMS can predict faults in the monitored subsystems before they occur.
The diagnostic and prognostic results delivered by data link service are automatically prioritized in accordance with user-specific criteria to assess the impact of fault conditions on future operation. If a critical anomaly is identified, that information is automatically transmitted to the ground crew. Aircraft maintainance and ground crews then use this information for operational and maintenance planning and take any corrective action needed.
On the ground, an off-board ACAMS combines all of the collected and analyzed in-flight data with historical information, such as component maintenance history, reliability and maintainability data, and—for commercial air carriers—quick-access recorder (QAR) and flight operations quality assurance (FOQA) data. The system analyzes these data for higher fidelity diagnosis and prognosis, helping to facilitate long-term, fleet-wide aircraft dispositioning and improve maintenance scheduling and parts supply management
Historically, navigation information was displayed on a group of instruments called the basic or primary six, which included the attitude indicator, a vertical speed indicator showing the rate of climb and descent, airspeed indicator, turn-and-bank coordinator, a heading indicator (directional gyro) showing the magnetic compass course, and the altimeter. These instruments are still used and called the primary flight display, having developed now from mechanical dials to electronic flight information displays.
The avionics displays and aircraft instruments of the future are now known as the glass cockpit and (as digital and sensor technology has advanced) include air data computers and head-up displays. This, of course coincides, with there being an increasingly unmanageable number (over 100) cockpit instruments.
In the same manner, mechanical flight control systems are being replaced by fly-by-wire and fly-by-optics.
Radar has developed with Airborne collision avoidance systems ACAS... traffic alert and collision avoidance system TCAS...
The Airborne Collision Avoidance System (ACAS II) operates software level 7
(Change 7) and is mandatory in Europe.
The software difference for the European ACAS II is consistent with the RVSM requirement of 1,000 ft separation for all aircraft flying between FL290 and FL410. The European ACAS II is designed principally to eliminate nuisance warnings when an aircraft is flying within RVSM airspace.
TCAS II operates as an airborne secondary surveillance radar that interrogates the ATC transponders of nearby aircraft. Range, relative bearing and altitude of the nearby aircraft are measured by the TCAS II system. The system provides both aural and visual warnings in the event TCAS II predicts a near miss or potential collision. TCAS II depicts aircraft with operating Mode C or Mode S transponders on one or more instrument panel displays.
TCAS II installation is mandated in United States airspace for aircraft with more than 30 passenger seats. TCAS II with Change 7 satisfies the requirements imposed by the International Civil Aviation Organisation (ICAO) called Airborne Collision Avoidance System (ACASII). ACAS has been mandated in Europe since January 2000.
TCAS-commanded avoidance manoeuvres are in the vertical plane only, so Resolution Advisory (RA) commands appear on the two vertical speed instruments or the vertical speed display fields of integrated electronic flight display systems.
TCAS:
- Enhances a crew's situational awareness of nearby traffic
- Enhances safety by detecting and displaying potential collision threats
- Computes avoidance manouvers with aural and visual commands
- Coordinates complementary commands in encounters with other TCAS II-equipped aircraft.
EGPWS enhanced ground proximity warning systems also uses the power of computing and technological advances of GPS navigation equipment.
It is common that the majority of commercial aircraft nowadays carry an Airborne Weather Radar system that is most often built into the aircraft nose. Airborne Weather Radar Systems provide the pilot with a local (ahead only) weather picture in the cockpit and allows him to identify and avoid specific, undesirable weather formations. A maximum range of 180 Nm is common although the commonly used range (as selected by pilots) would normally be in the 30 to 80 Nm range.
Mission or tactical avionics include weather systems like radar enhanced vision systems giving military pilots "eyes". Like radar, sonar is still used in airborne weaponry.
Laser and electro-optical systems LEOS have been developed by Boeing as tactical avionics used against ground targets.
Civil aviation safety legal requirements drive the market for many developments in avionics... fdrs, cvrs, elts, epirbs.
Large commercial aircraft and some smaller commercial, corporate, and private aircraft are required by the FAA to be equipped with two "black boxes" that record information about a flight. Both recorders are installed to help reconstruct the events leading to an aircraft accident. One of these, the Cockpit Voice Recorders (CVRs), records radio transmissions and sounds in the cockpit, such as the pilot's voices and engine noises. The other, the Flight Data Recorders (FDRs), monitors parameters such as altitude, airspeed and heading. The older analog units use one-quarter inch magnetic tape as a storage medium and the newer ones use digital technology and memory chips. Both recorders are installed in the most crash survivable part of the aircraft, usually the tail section.
Each recorder is equipped with an Underwater Locator Beacon (ULB) to assist in locating in the event of an overwater accident. The device called a "pinger", is activated when the
recorder is immersed in water. It transmits an acoustical signal on 37.5 KHz that can be detected with a special receiver. The beacon can transmit from depths down to 14,000 feet.
ELTs emergency locator transmitters were the first emergency beacons developed and most U.S. civil aircraft are required to carry them. ELTs were intended for use on the 121.5 MHz frequency to alert aircraft flying overhead. Obviously, a major limitation to these is that another aircraft must be within range and listening to 121.5 MHz to receive the signal. One of the reasons the Cospas-Sarsat system was developed was to provide a better receiving source for these signals. Another reason was to provide location data for each activation (something that overflying aircraft were unable to do).
Different types of ELTs are currently in use. There are approximately 170,000 of the older generation 121.5 MHz ELTs in service. Unfortunately, these have proven to be highly ineffective. They have a 97% false alarm rate, activate properly in only 12% of crashes, and provide no identification data. In order to fix this problem 406 MHz ELTs were developed to work specifically with the Cospas-Sarsat system. These ELTs dramatically reduce the false alert impact on SAR resources, have a higher accident survivability success rate, and decrease the time required to reach accident victims by an average of 6 hours.
Presently, most aircraft operators are mandated to carry an ELT and have the option to choose between either a 121.5 MHz ELT or a 406 MHz ELT. From January 1st 2005 the Federal Aviation Administration has mandated carriage of 406 MHz ELTs. Studies indicated that 134 extra lives and millions of dollars in SAR resources could be saved per year. The only problem is that 406 MHz ELTs currently cost about $1,500 and 121.5 MHz ELTs cost around $500. It's easy to see one reason for the cost differential when you look at the numbers.However, no one can argue the importance of 406 MHz ELTs and the significant advantages they hold.
EPIRBs emergency position indicating radio beacons are similar for maritime use.