If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
|
Thread Tools | Display Modes |
#1
|
|||
|
|||
GPS missed approach question
You're supposed to go missed if you have a RAIM or GPS failure message.
But all the GPS IAP's I've seen have missed approaches that require use of the GPS to fly correctly (fly to this waypoint, then go to this other waypoint and hold). So what do you do? Use the GPS to fly the missed despite the RAIM failure (assuming the whole GPS hasn't gone belly up)? Call ATC for help? |
#2
|
|||
|
|||
"xyzzy" wrote in message ... You're supposed to go missed if you have a RAIM or GPS failure message. But all the GPS IAP's I've seen have missed approaches that require use of the GPS to fly correctly (fly to this waypoint, then go to this other waypoint and hold). So what do you do? Use the GPS to fly the missed despite the RAIM failure (assuming the whole GPS hasn't gone belly up)? Call ATC for help? This isn't peculiar to GPS approaches. What do you do on a VOR approach when the VOR fails and it's needed for the missed approach procedure? |
#3
|
|||
|
|||
xyzzy wrote:
You're supposed to go missed if you have a RAIM or GPS failure message. But all the GPS IAP's I've seen have missed approaches that require use of the GPS to fly correctly (fly to this waypoint, then go to this other waypoint and hold). So what do you do? Use the GPS to fly the missed despite the RAIM failure (assuming the whole GPS hasn't gone belly up)? Call ATC for help I have experienced a RAIM failure during a GPS approach, but the GPS was still able to provide terminal resolution guidance to the missed approach point. Another time I experienced a complete GPS failure during an approach (BK KLN-94), but in that case I requested vectors from ATC. -- Peter ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
#4
|
|||
|
|||
The GPS doesn't stop working when you get a RAIM warning. All RAIM
means is the accuracy can't be verified. I have gotten quite a few RAIM messages on my GX55, if not for the warning you would never have known it. The GPS hums along nicely. xyzzy wrote: You're supposed to go missed if you have a RAIM or GPS failure message. But all the GPS IAP's I've seen have missed approaches that require use of the GPS to fly correctly (fly to this waypoint, then go to this other waypoint and hold). So what do you do? Use the GPS to fly the missed despite the RAIM failure (assuming the whole GPS hasn't gone belly up)? Call ATC for help? |
#5
|
|||
|
|||
xyzzy wrote:
You're supposed to go missed if you have a RAIM or GPS failure message. But all the GPS IAP's I've seen have missed approaches that require use of the GPS to fly correctly (fly to this waypoint, then go to this other waypoint and hold). So what do you do? Use the GPS to fly the missed despite the RAIM failure (assuming the whole GPS hasn't gone belly up)? Call ATC for help? A Raim Warning you should still have GPS and can execute the missed. I have had a complete failure of the GPS just past the FAF and in the soup. Approach had just told me to go to advisory. My action was to level off, hit the switch back to approach, advise them of the situation and request a vector, a the while holding the final approach course. I knew I would be safe for a period of time on that course. ATC then told me I could descend 300 more feet, the ATIS had reported the ceiling should be 300 feet below me so I took a chance and broke out with the center line of the runway straight ahead of me and could make a normal landing. Scott -- -------------------- Scott F. Migaldi CP-ASEL-IA N8116B PADI MI-150972 Join the PADI Instructor Yahoo Group http://groups.yahoo.com/group/PADI-Instructors/ -------------------- |
#6
|
|||
|
|||
xyzzy wrote in :
You're supposed to go missed if you have a RAIM or GPS failure message. But all the GPS IAP's I've seen have missed approaches that require use of the GPS to fly correctly (fly to this waypoint, then go to this other waypoint and hold). So what do you do? Use the GPS to fly the missed despite the RAIM failure (assuming the whole GPS hasn't gone belly up)? Call ATC for help? As others have said, the GPS will still work, you just won't be assured of enough accuracy for the approach at MDA. You will still have plenty of accuracy for holding at the MAP holding fix, though. For holding you just need to be in the general vicinity. Also, you can continue the approach if the RAIM warning happens after the FAF. The RAIM warning means that there is a prediction of lower accuracy sometime in the future, probably after you finish the approach, unless your groundspeed is very slow. -- Regards, Stan "They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety." B. Franklin |
#7
|
|||
|
|||
"Stan Gosnell" wrote in message ... xyzzy wrote in : You're supposed to go missed if you have a RAIM or GPS failure message. But all the GPS IAP's I've seen have missed approaches that require use of the GPS to fly correctly (fly to this waypoint, then go to this other waypoint and hold). So what do you do? Use the GPS to fly the missed despite the RAIM failure (assuming the whole GPS hasn't gone belly up)? Call ATC for help? As others have said, the GPS will still work, you just won't be assured of enough accuracy for the approach at MDA. So what is meant by a GPS failure message then? |
#8
|
|||
|
|||
Stan Gosnell wrote:
As others have said, the GPS will still work, you just won't be assured of enough accuracy for the approach at MDA. You will still have plenty of accuracy for holding at the MAP holding fix, though. I think you mean only when there is a RAIM warning does the GPS still provide course navigation. When I experienced a GPS error message with the KLN-94, the GPS was completely useless and needed to be recycled before it began working again, much like a computer hard-boot. It is also worth noting that this particular error only happened this one time with the KLN94. Having a few hundred hours now behind a GNS430, I have never experienced any type of GPS system error or RAIM error with the Garmin. -- Peter ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
#9
|
|||
|
|||
Peter R. wrote:
Stan Gosnell wrote: As others have said, the GPS will still work, you just won't be assured of enough accuracy for the approach at MDA. You will still have plenty of accuracy for holding at the MAP holding fix, though. I think you mean only when there is a RAIM warning does the GPS still provide course navigation. When I experienced a GPS error message with the KLN-94, the GPS was completely useless and needed to be recycled before it began working again, much like a computer hard-boot. It is also worth noting that this particular error only happened this one time with the KLN94. Having a few hundred hours now behind a GNS430, I have never experienced any type of GPS system error or RAIM error with the Garmin. The new RNAV (RNP) criteria presume a complete loss of GPS for the missed approach. If the airspace/obstacle environment will permit a heading or track to a VOR missed approach in the event of loss of GPS, then no backup is required. If the missed approach areas are too tight then dual or triple IRUs are required. With the present RNAV (GPS) approaches the presumption is that flying headings will get you out of the woods until you can either get a vector or receive a VOR. There is some risk with this presumption. |
#10
|
|||
|
|||
On Sat, 10 Sep 2005 17:30:27 GMT, Tim wrote:
The new RNAV (RNP) criteria presume a complete loss of GPS for the missed approach. If the airspace/obstacle environment will permit a heading or track to a VOR missed approach in the event of loss of GPS, then no backup is required. If the missed approach areas are too tight then dual or triple IRUs are required. Where is that requirement spelled out for Part 91 operators using GPS (single-sensor)? I don't see it in AC90-100, but that does not deal with missed approaches. Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA) |
|
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
GPS approach question | Matt Whiting | Instrument Flight Rules | 30 | August 29th 08 03:54 AM |
Contact approach question | Paul Tomblin | Instrument Flight Rules | 114 | January 31st 05 06:40 PM |
Approach Question- Published Missed Can't be flown? | Brad Z | Instrument Flight Rules | 8 | May 6th 04 04:19 AM |
Where is the FAF on the GPS 23 approach to KUCP? | Richard Kaplan | Instrument Flight Rules | 36 | April 16th 04 12:41 PM |
Missed approach procedure... | [email protected] | Instrument Flight Rules | 39 | November 11th 03 03:46 PM |