Number 217
July 1997
Going Global with GPS
As the cost of Global Positioning System (GPS) units decreases, more pilots are using these devices to supplement their other navigational equipment. However, problems can arise when some pilots fail to recognize that GPS is designed to be a supplemental—not a primary—navigational aid. A report from a corporate pilot illustrates: put in orbit; there were now a total of 26 satellites. My unit only showed 25. The manufacturer suggested leaving the GPS on for 45 minutes to acquire the information from the new satellite. I did so, and my unit now shows 26 satellites. The GPS positions seem correct. Conclusion: use hand-held GPS as a reference only. According to the reporter’s conversation with the manufacturer, hand-held GPS units currently in use do not have the RAIM—Receiver Autonomous Integrity Monitor— that is built into installed, IFR-certified units. The RAIM monitors the actual navaid signal, primarily on SID and STAR routes, to assure that there is adequate signal strength for navigation in the selected mode. If the signal is not sufficient, an error message will occur. This is analogous to the ‘OFF’ flag showing on the VOR receiver when the aircraft is out of range for adequate signal acquisition. Since the reporter’s GPS unit did not have RAIM capability, there was no way to know that the unit was providing erroneous information. Because of the inherent limitations of hand-held units, pilots should carry and use the appropriate charts as cross-reference material, rather than relying solely on GPS.
s I departed on an IFR flight plan with an IFR-approved
GPS. I was cleared direct to ABC, at which time I dialed ABC into the VOR portion of the GPS and punched “direct.” The heading was 040 degrees. After a few minutes, Approach inquired as to my routing, heading, etc. I stated direct ABC, 040 degrees. They suggested turning to 340 degrees for ABC. I was dumbfounded. My GPS receiver had locked to ADC, 3,500 miles away [in Norway]! Closer inspection revealed that my estimated time en route was 21 hours. I did not verify my position with the VOR receiver. I mistakenly, blindly, trusted a GPS. Now that is truly global positioning! Other reporters have found themselves somewhere other than where they wanted to be as a result of overreliance on GPS. A general aviation pilot provides an example:
s I recently purchased a hand-held GPS, and was
anxious to use my new acquisition. Without thinking (obviously!), I punched in XYZ VOR and navigated along the direct route. I did not cross-check myself with the VORs and allowed myself to invade restricted airspace. I tuned in 121.5, and received instructions and polite guidance out of my dilemma. I realize that this is a serious problem and a very stupid mistake.
GPS Water Rescue
When properly programmed and used, GPS has incredibly accurate position reporting capability, which can prove to be a lifesaver—literally. The next reporter, the pilot of a long-range amphibious airplane on a ferry flight across the Pacific Ocean, tells a “GPS-to-the-rescue” story.
Limits of Hand-Held GPS
Many hand-held GPS units have an inherent system limitation, as our next reporter discovered.
s While we were ferrying the aircraft…the left engine
began backfiring severely and would not develop [power]. Engine #2 was brought to METO [Maximum Except TakeOff] power attempting to maintain best altitude. An immediate turn was made for the nearest land, and our “Pan” emergency shifted to a “Mayday” call. After about one hour, descent into the water was imminent. The night ocean visibility would be termed zero/zero...and a standard night IFR approach was set up. After a successful night IFR water landing, we began taking on water. Seven people escaped without injury into a lifeboat. Coordination with ATC and very accurate position reporting with GPS resulted in a very expeditious rescue by the Coast Guard and a maritime vessel. We were in the ocean less than one day. Very spectacular efforts by all parties involved. May 1997 Report Intake
Air Carrier Pilots General Aviation Pilots Controllers Cabin/Mechanics/Military/Other 1798 701 69 38
s Flying VFR, using a hand-held GPS for navigational reference. While en route, position and status seemed fine. According to the GPS position, a “big airport” was getting closer and closer, but still out of the overlying Class C airspace. From a visual standpoint, the position was definitely in Class C airspace. When I landed at ABC, the GPS indicated the location was XYZ [about 40 nm west]. I turned the unit off, then back on, and the position now indicated ABC.
I called the manufacturer, which had received numerous calls about erroneous positions. A new satellite had been ASRS Recently Issued Alerts On...
Engine failures in an MD-80 and an MD-88 Parachute jumping activity near a Nevada arrival route Erroneous computerized groundspeeds at a Utah Center BAe-31 engine reversal due to propeller governor failure Autopilot and elevator trim malfunctions on a Beech King Air
A Monthly Safety Bulletin from The Office of the NASA Aviation Safety Reporting System, P.O. Box 189, Moffett Field, CA 94035-0189 http://olias.arc.nasa.gov/asrs
TOTAL
2606
飞行翻译公司 www.aviation.cn 本文链接地址：美国ASRS安全公告CALLBACK cb_217.pdf
July 1997
Going Global with GPS
As the cost of Global Positioning System (GPS) units decreases, more pilots are using these devices to supplement their other navigational equipment. However, problems can arise when some pilots fail to recognize that GPS is designed to be a supplemental—not a primary—navigational aid. A report from a corporate pilot illustrates: put in orbit; there were now a total of 26 satellites. My unit only showed 25. The manufacturer suggested leaving the GPS on for 45 minutes to acquire the information from the new satellite. I did so, and my unit now shows 26 satellites. The GPS positions seem correct. Conclusion: use hand-held GPS as a reference only. According to the reporter’s conversation with the manufacturer, hand-held GPS units currently in use do not have the RAIM—Receiver Autonomous Integrity Monitor— that is built into installed, IFR-certified units. The RAIM monitors the actual navaid signal, primarily on SID and STAR routes, to assure that there is adequate signal strength for navigation in the selected mode. If the signal is not sufficient, an error message will occur. This is analogous to the ‘OFF’ flag showing on the VOR receiver when the aircraft is out of range for adequate signal acquisition. Since the reporter’s GPS unit did not have RAIM capability, there was no way to know that the unit was providing erroneous information. Because of the inherent limitations of hand-held units, pilots should carry and use the appropriate charts as cross-reference material, rather than relying solely on GPS.
s I departed on an IFR flight plan with an IFR-approved
GPS. I was cleared direct to ABC, at which time I dialed ABC into the VOR portion of the GPS and punched “direct.” The heading was 040 degrees. After a few minutes, Approach inquired as to my routing, heading, etc. I stated direct ABC, 040 degrees. They suggested turning to 340 degrees for ABC. I was dumbfounded. My GPS receiver had locked to ADC, 3,500 miles away [in Norway]! Closer inspection revealed that my estimated time en route was 21 hours. I did not verify my position with the VOR receiver. I mistakenly, blindly, trusted a GPS. Now that is truly global positioning! Other reporters have found themselves somewhere other than where they wanted to be as a result of overreliance on GPS. A general aviation pilot provides an example:
s I recently purchased a hand-held GPS, and was
anxious to use my new acquisition. Without thinking (obviously!), I punched in XYZ VOR and navigated along the direct route. I did not cross-check myself with the VORs and allowed myself to invade restricted airspace. I tuned in 121.5, and received instructions and polite guidance out of my dilemma. I realize that this is a serious problem and a very stupid mistake.
GPS Water Rescue
When properly programmed and used, GPS has incredibly accurate position reporting capability, which can prove to be a lifesaver—literally. The next reporter, the pilot of a long-range amphibious airplane on a ferry flight across the Pacific Ocean, tells a “GPS-to-the-rescue” story.
Limits of Hand-Held GPS
Many hand-held GPS units have an inherent system limitation, as our next reporter discovered.
s While we were ferrying the aircraft…the left engine
began backfiring severely and would not develop [power]. Engine #2 was brought to METO [Maximum Except TakeOff] power attempting to maintain best altitude. An immediate turn was made for the nearest land, and our “Pan” emergency shifted to a “Mayday” call. After about one hour, descent into the water was imminent. The night ocean visibility would be termed zero/zero...and a standard night IFR approach was set up. After a successful night IFR water landing, we began taking on water. Seven people escaped without injury into a lifeboat. Coordination with ATC and very accurate position reporting with GPS resulted in a very expeditious rescue by the Coast Guard and a maritime vessel. We were in the ocean less than one day. Very spectacular efforts by all parties involved. May 1997 Report Intake
Air Carrier Pilots General Aviation Pilots Controllers Cabin/Mechanics/Military/Other 1798 701 69 38
s Flying VFR, using a hand-held GPS for navigational reference. While en route, position and status seemed fine. According to the GPS position, a “big airport” was getting closer and closer, but still out of the overlying Class C airspace. From a visual standpoint, the position was definitely in Class C airspace. When I landed at ABC, the GPS indicated the location was XYZ [about 40 nm west]. I turned the unit off, then back on, and the position now indicated ABC.
I called the manufacturer, which had received numerous calls about erroneous positions. A new satellite had been ASRS Recently Issued Alerts On...
Engine failures in an MD-80 and an MD-88 Parachute jumping activity near a Nevada arrival route Erroneous computerized groundspeeds at a Utah Center BAe-31 engine reversal due to propeller governor failure Autopilot and elevator trim malfunctions on a Beech King Air
A Monthly Safety Bulletin from The Office of the NASA Aviation Safety Reporting System, P.O. Box 189, Moffett Field, CA 94035-0189 http://olias.arc.nasa.gov/asrs
TOTAL
2606
飞行翻译公司 www.aviation.cn 本文链接地址：美国ASRS安全公告CALLBACK cb_217.pdf
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