9近地警告系统

近地告警系统（EGPWS）
电子信息工程学院
5
GENERAL DESCRIPTION
The ground proximity warning system (GPWS) alerts the flight crew of an unsafe condition when the airplane is near the terrain. It also supplies a warning for windshear conditions. The GPWS uses global positioning system (GPS) and loadable software data bases to give the flight crew improved terrain awareness. This is done by the display of detailed terrain information for the area around the aircraft. The GPWS also warns the flight crew of an early descent. The GPWS uses aural messages, lights, and displays to give alerts in the flight compartment. The GPWS gives the pilots aural and visual warnings of unsafe conditions. The warnings continue until the pilots correct the condition.
近地告警系统（EGPWS）
电子信息工程学院
11
GENERAL DESCRIPTION
Ground proximity warning module (GPWM) Radio altimeter (RA) Air data inertial reference system (ADIRS) Stall management yaw dampers (SMYDs) Multi-mode receivers (MMRs) Flight management computer system (FMCS) Weather radar (WXR) Display electronics units (DEUs).
近地警告系统 （GPWS）
中国民航大学 电子信息工程学院
Alert system
近地告警系统（EGPWS）
电子信息工程学院
2
CFIT（可控飞行撞地）
CFIT: Controlled flight into terrain. 为民航两大 主要航空事故之一（ALA： Approach and Landing）， 为一架飞机由机师正常控制，但因为一些失误而撞上地 面、阻碍物或水面坠毁。 根据国际民航组织的统计，可控飞行撞地目前已经成为 商用喷气飞机机体损毁事故和人员死亡事故的元凶。 1974年，FAA开始对在美国空域飞行的航班上的GPWS进行 强制安装要求（Honeywell），此后CFIT事故急剧减少。 1985年后，CFIT事故每年仅发生1到2次，而强制要求安 装前每年发生7到8次。目前，全球几乎所有的商用喷气 飞机均装备GPWS。 GPWS is a system developed to help prevent CFIT accidents.
近地告警系统（EGPWS）
电子信息工程学院
7
EGPWS
Enhanced Ground Proximity Warning Systems (EGPWS), also called Terrain Awareness Warning Systems(TAWS). A limitation of GPWS is the fact that with radar altimeter information the aircraft is only capable of seeing terrain directly below. In the case of rapidly rising terrain it may not react quick enough to issue a warning in time. EGPWS corrects this problem by integrating an aircraft navigational source into the system. GPS position in conjunction with a terrain database is used to help predict terrain conflict.
近地告警系统（EGPWS）
电子信息工程学院
6
GENERAL DESCRIPTION
The enhanced GPWS function contains a worldwide terrain data base. The GPWC compares airplane position and track with this data base to find if there is a warning condition. This is the terrain awareness function. The enhanced GPWS also contains an airport data base. This data base contains terrain information for all hard surface runways that are more than 3500 feet or longer. The GPWC compares airplane position and runway location to find if there is a warning condition. This is the terrain clearance floor (TCF) function. The GPWS sends inhibit signals to the TCAS and weather radar systems when GPWS calculates cautions and warnings.
近地告警系统（EGPWS）
电子信息工程学院

4
GPWS
概念：地面迫近警告系统（GPWS, Ground Proximity Warning System），又称近地警告系统， 是防止飞机因为离地过近而发生 事故的系统，与TCAS搭配成为保 护飞航安全的两大防线。 原理：GPWS在起飞开始到降落地 面为止，持续监视飞机离地高度， 利用无线电高度表获得离地高度， 并且以电脑计算出飞机的飞行趋 势，若有危险时会以视觉与语音 警告飞行员采取避险措施。
近地告警系统（EGPWS）
电子信息工程学院
8
GPWS Modes
Mode 1 - Large descent rates Mode 2 - Too much of a closure rate when approaching terrain that is rising Mode 3 - Too much altitude loss during climbout (at takeoff or in go around) when the airplane is not in the landing configuration Mode 4 - Not enough terrain clearance Mode 5 - Too much deviation below the glideslope Mode 6 - Aural callouts when the airplane descends through selected radio altitudes Mode 7 - Warning for windshear conditions.
approach Approach Take off
<1500ft
Caution, wind shear Wind shear
10
Operation mode
Mode 1: Excessive Descent Rate(过度的下降速率)。（"SINK RATE" "PULL UP"） Mode 2: Excessive Closure to Terrain(过度的地障接近率)。 （"TERRAIN...TERRAIN" "PULL UP"） Mode 3: Altitude Loss After Takeoff(在航机起飞（Takeoff）或 重飞（Go around）爬升时航机高度值过度下降(Altitude loss))。 （"DON'T SINK"） Mode 4: Unsafe Terrain Clearance(与地障的间距不足)（未放下起 落架或襟翼小于30度等）。（"TOO LOW - TERRAIN" "TOO LOW GEAR" "TOO LOW - FLAPS"） Mode 5: Excessive Deviation Below Glide slope(仪器降落时与下 滑道（Glide slope）的误差过大)。("GLIDE SLOPE") Mode 6: Advisory Callouts(正常下降时的提醒)。(“Bank Angle” “Five Hundred” “Minimums”) Mode 7: Windshear Alerting(当飞机遭受风切变警讯)。(“Caution, Windshear” “Windshear, Windshear, Windshear”)