航空電子設(shè)備-增強(qiáng)型近地警告系統(tǒng)

1、 Civil Aviation Flight University of China Enhanced Ground Proximity Warning System增強(qiáng)型近地警告系統(tǒng)Enhanced Ground Proximity Warning System(EGPWS) Civil Aviation Flight University of China The GPWS used today has limitations that may contribute to the “Late warning or improper pilot response” and “No warni

2、ng” categories. Current GPWS alerting functions reply on radio altimeters that cannot sense terrain ahead of the airplane. The result can be very short warning times for flight into quickly rising terrain. Additionally, when on approach at a normal descent rate with gear and flaps in the landing con

3、figuration, no terrain warnings are provided, because the GPWS assumes the airplane will land at an airplane. A new generation of GPWS the Enhanced GPWS (EGPWS) is designed to complement the current functions of the GPWS and provide terrain warnings in situations where the current system does not.En

4、hanced Ground Proximity Warning System(EGPWS)事故一 1995年12月20日，美利堅航空公司的一架B757飛機(jī)（965航班）墜毀于南美哥倫比亞的卡利（Cali）。飛機(jī)撞山前11秒GPWS發(fā)出了地形警告，然后墜毀于機(jī)場北38海里的12000英尺高的山上，離山頂200英尺處。 事故二 1996年4月，美國空軍的一架CT-43A運輸機(jī)墜毀于克羅地亞（Croatia）。事故處于襟翼和起落架都放下的正常進(jìn)近中，GPWS已解出了工作。 Civil Aviation Flight University of China Enhanced Ground Proxim

5、ity Warning System(EGPWS)Enhanced GPWS Features In addition to retaining current GPWS alerting functions, the EGPWS offers two new major features : Look-ahead terrain alerting. Terrain display. Civil Aviation Flight University of China Figure 9.1 Enhanced Ground Proximity Warning System(EGPWS) Look-

6、ahead terrain alerting. Terrain display. Civil Aviation Flight University of China Enhanced Ground Proximity Warning System(EGPWS)Look-ahead Terrain Alerting The EGPWS provides caution-andwarning-level alerts to the flight crew about potential terrain conflicts earlier than is possible with the basi

7、c GPWS. The alerts are based primarily on the airplane position and barometric altitude information passed to the EGPWS. Either a flight management system (FMS) or global positioning system (GPS) can provide airplane position (latitude and longitude) to the EGPWS. Figure 9.2 Civil Aviation Flight Un

8、iversity of China Enhanced Ground Proximity Warning System(EGPWS) The barometric altitude referenced to Mean Sea Level (QNH) is provided by the airplane air data system. The EGPWS uses additional air data inputs to determine the airplane flight path and orient the alerting envelopes appropriately. T

9、he terrain alerting algorithms continuously computer terrain clearance envelopes ahead of the airplane, which are vertically aligned with the airplane flight path and laterally aligned with the airplane ground track. If these envelopes conflict with data in the terrain database, alerts are activated

10、. The look-ahead caution alert is provided approximately 40 to 60 seconds before a potential terrain conflict, and the look-ahead warning alert is provided approximately 20 to 30 seconds before such a conflict. Civil Aviation Flight University of China Figure 9.2Enhanced Ground Proximity Warning Sys

11、tem(EGPWS) Civil Aviation Flight University of China Enhanced Ground Proximity Warning System(EGPWS) The alerting envelopes are sized by a look-ahead distance in front of the airplane, an altitude offset below the airplane, and a lateral distance on either side of the airplane. The look-ahead distan

12、ce varies mainly with ground speed. An additional component looks six degrees up to protect against very high terrain. This six-degree component actually looks ahead approximately twice the normal look-ahead distance. The altitude offset is normally 700 feet (213m) below the airplane. The purpose of

13、 the offset is to provide terrain alerting when the airplane has less than the normal terrain clearance. The lateral distance is 1/8 nautical mile (0.23km) either side of the airplane ground track and increase gradually out to the look-ahead distance. Civil Aviation Flight University of China Enhanc

14、ed Ground Proximity Warning System(EGPWS) In addition to the look-ahead alerting envelopes, the EGPWS has an additional element of protection, the terrain clearance floor (TCF), which addresses such cases as a barometric altitude error. The TCF is an alerting envelope around each airport based on ai

15、rplane radio altitude. On a normal three-degree glide path to a runway, the airplane will remain well clear of the TCF alerting envelope. If the airplane penetrates the TCF envelope, it is normally also penetrating the new EGPWS look-ahead alerting envelope, which is based on barometric altitude, so

16、 the look-ahead alerts would activate. However, if a barometric altitude error exists, the TCF would provide a radio altitude-based alert. Civil Aviation Flight University of China Figure 9.3Enhanced Ground Proximity Warning System(EGPWS)TCF envelopeTCF envelope EGPWS的功能 TCF包線 Civil Aviation Flight

17、University of China Enhanced Ground Proximity Warning System(EGPWS)Terrain Display The EGPWS terrain display is designed to increase flight crew awareness of the surrounding terrain and to potentially avoid terrain conflicts entirely. The terrain display can be selected manually by the flight crew o

18、r displayed automatically when a look-ahead caution or warning alert activates. The terrain is displayed on the Electronic Horizontal Situation Indicator (EHSI) or navigation display, or on a dedicated weather radar display in flight decks without map displays. The terrain is shown on the display in

19、 dotted patterns of red, amber, and green, with the colors indicating the height of the terrain relative to the current airplane altitude . Civil Aviation Flight University of China Figure 9.4Enhanced Ground Proximity Warning System(EGPWS) Civil Aviation Flight University of China Enhanced Ground Pr

20、oximity Warning System(EGPWS) Dotted red. This pattern indicates significantly high terrain (greater than 2,000 feet (610m) above the airplane altitude), which is a potential threat if the terrain is displayed ahead of the airplane. Dotted amber. This pattern also indicates a potential threat if dis

21、played ahead of the airplane, signifying terrain extending anywhere from 500 feet (152m) below the current airplane altitude to 2,000 feet (610m) above. Dotted green. This pattern indicates terrain for which the airplane has sufficient clearance at its current altitude (500 feet (152m) or more), but

22、 which is close enough that the flight crew should be aware of its presence. Two different dot densities of amber and green increase the contouring effect of the display. Civil Aviation Flight University of China Enhanced Ground Proximity Warning System(EGPWS) To reduce clutter on the display, any t

23、errain more than 2,000 feet (610m) below the airplane is not displayed, and instead remains the background color of black. Because the terrain colors are displayed relative to the current airplane altitude, the colors will change as the airplane climbs or descends. In those areas of the world for wh

24、ich the EGPWS terrain database does not yet contain terrain data, a dotted magenta pattern will show on the display. Civil Aviation Flight University of China Enhanced Ground Proximity Warning System(EGPWS) When a caution or warning look-ahead alert is activated, the terrain display is enhanced with

25、 solid amber and red patterns . For the caution alert, the terrain creating the conflict in front of the airplane is displayed in solid amber, as well as terrain of equal or greater elevation 90 degrees left and right of the nose of the airplane. Terrain that was displayed as dotted red prior to the

26、 caution alert remains unchanged to emphasize its significant height. For the warning alert, terrain creating the conflict in front of the airplane is displayed in solid red, as well as terrain of equal or greater elevation 90 degrees left and right of the nose of the airplane. No change to the terr

27、ain display occurs with a TCF alert or any basic GPWS alert. Civil Aviation Flight University of China Figure 9.5 Civil Aviation Flight University of China Enhanced Ground Proximity Warning System(EGPWS) The captain and first officer can manually select the terrain display on Electronic Flight Instr

28、ument System (EFIS) control panel so they can monitor the terrain during a departure or approach. To ensure that terrain information is available to the flight crew, the system automatically displays the terrain when a look-ahead alert occurs. If terrain is not displayed on either the captains or fi

29、rst officers map display when a look-ahead caution or warning alert activates, terrain is automatically displayed on both map displays. If terrain is already displayed on one map display when the alert activates, it will not automatically be displayed on the other map display. Civil Aviation Flight

30、University of China Figure 9.6 Enhanced Ground Proximity Warning System(EGPWS) Civil Aviation Flight University of China Enhanced Ground Proximity Warning System(EGPWS)EGPWS Alerting Flight Deck Effects Caution Alert Illumination of the amber ground proximity light is the same as with the caution le

31、vel alerts of the current GPWS. The voice aural, terrain display and annunciations on the map display are unique to the new EGPWS. Civil Aviation Flight University of China Figure 9.7Enhanced Ground Proximity Warning System(EGPWS) Civil Aviation Flight University of China Enhanced Ground Proximity W

32、arning System(EGPWS) Warning Alert The voice aural, illumination of the red master warning light and the red PULL-UP annunciation are the same as with the PULL-UP warning level alerts of the current GPWS. The terrain display and annunciations on the map display are unique to the new EGPWS. Civil Avi

33、ation Flight University of China Figure 9.8Enhanced Ground Proximity Warning System(EGPWS) Civil Aviation Flight University of China Enhanced Ground Proximity Warning System(EGPWS) TCF Alert The flight deck effects for the TCF alert are the TOO LOW TERRAIN voice aural and illumination of the amber g

34、round proximity light (red PULL-UP light; 737 only). These indications are identical to the current GPWS caution-level alerts. 地形顯示和前視報警自動地形顯示 Civil Aviation Flight University of China Enhanced Ground Proximity Warning System(EGPWS)Flight Crew Procedures If an alert occurs when flying under daylight

35、 Visual Meteorological Conditions (VMC) and the flight crew can make a positive visual verification that no hazard exists, the flight crew should regard the alert as cautionary. Otherwise, the following procedures apply for a caution, TCF, or warning alert.Caution or TCF Alert Verify the airplane fl

36、ight path and correct if necessary. If terrain clearance is in doubt, the flight crew should perform the terrain avoidance maneuver.Warning Alert Perform the terrain avoidance maneuver immediately until the flight deck indications show that the airplane is clear of the terrain. Civil Aviation Flight

37、 University of China Enhanced Ground Proximity Warning System(EGPWS) Terrain Avoidance The following is immediately accomplished by recall whenever the threat of inadvertent contact with the terrain exists. Any of the following conditions is regarded as presenting a potential threat for terrain contact: Activation of the “PULL-UP” warning Other situations resulting in unacceptable flight toward terrainFlight Crew Procedures Civil Aviation Flight University of China Enhanced Ground Proximity Warning System(EGPWS)PILOT FLYINGPILOT NOT FLYING Disconnect autopilot. Disco