Quote: Incident one occurred in August on a westbound United Boeing 767 from San Francisco to Hawaii. A pilot-trained passenger happened to notice that three hours out, the airplane made a slow 180-degree turn back toward the west coast. Shortly thereafter, a PA from the flight deck said that the aircraft had lost all navigational capability. The crew had declared an emergency, climbed to 34,500 feet for additional separation and was aiming for California. It eventually was assigned a hard altitude and landed in San Francisco without incident. As far as I know, the incident didn't make it into the news cycle. Our correspondent told us she spoke to the crew, who said they navigated home with a whiskey compass and an iPad…in a multi-million dollar airplane with a half-million dollar glass panel. All the better reason to keep a basic text on your iPad refreshing your memory of northerly compass turning error.
Can anyone here shed some more light on this incident? It looks pretty serious and I can't find any more info about this on the internet.
fr8mech From United States of America, joined Sep 2005, 4265 posts, RR: 12 Reply 1, posted (6 months 3 weeks 4 days 21 hours ago) and read 3983 times:
A triple IRS failure? Plus a dual GPS failure? Plus a triple VOR failure (when in close to the coast)? Dual ADF failure? Unless they lost all 4 screens and their RDMI's, I just can't see that happening.
The power failure that would cause all those problems would be noticed in the back.
Methinks there was more, or more probably, less to this story.
The DC8 had a sextant hole. The classic jumbos had a hole that was called the smoke evacuation port but the urban mythology amongst the maintenance folks is that is could also be used to take sightings.
fr8mech From United States of America, joined Sep 2005, 4265 posts, RR: 12 Reply 19, posted (6 months 3 weeks 1 day 11 hours ago) and read 2835 times:
Quoting avantime (Thread starter): Can anyone here shed some more light on this incident? It looks pretty serious and I can't find any more info about this on the internet.
I'm a skeptic on this incident. So, I looked at some prints and tried to make 3ea IRS fail and both GPS fail without letting the people in the back know (i.e. dual IDG failure, with a failure of the standby buss) and I can't do it.
I'm calling BS on a story that was designed to make a point about electronics on aircraft.
KELPkid From United States of America, joined Nov 2005, 5936 posts, RR: 4 Reply 22, posted (6 months 3 weeks 1 day 7 hours ago) and read 2735 times:
Quoting HAWK21M (Reply 21): Seems very difficult to believe considering the range of navigation equipment available on the B767.
I wonder if they still carry an ADF receiver, as NDB's have been decomissioned by the droves here in the US. I realize that NDB's are still pretty common overseas, but even when NDB's were still fairly common in the US, in general aviation planes, if you had a GPS onboard, it was much more convienient and simpler to navigate using GPS overlay, especially when IFR.
If you have an ADF receiver, you can at least home in on a powerful AM radio station...
I know that other long range navigation systems (like Omega/VLF and LORAN) have been supplanted by GPS and GPS alone (well, with IRS as a backup on an airliner).
Once the aircraft was within ~130 miles of the US coast, the navigation system woud have started to pick up VOR/DME (assuming that much was operable...).
Celebrating the birth of KELPkidJR on August 5, 2009 :-)
Jetlagged From United Kingdom, joined Jan 2005, 2452 posts, RR: 17 Reply 24, posted (6 months 3 weeks 1 day 6 hours ago) and read 2701 times:
Quoting SKC (Reply 17): Maybe geographically, but quite possibly not closer when factoring in headwinds. May not have passed their equal time point, thus it was quicker to turn around and head back than to continue.
Without oceanic navigation ability, the chances of finding Hawaii are remote. However head back to the east and you will certainly find land.
Quoting KELPkid (Reply 22): I wonder if they still carry an ADF receiver, as NDB's have been decomissioned by the droves here in the US.
Not too many NDBs in the Pacific, so it's a moot point. But I'd be surprised if ADFs had been removed.
Quoting fr8mech (Reply 19): I'm a skeptic on this incident. So, I looked at some prints and tried to make 3ea IRS fail and both GPS fail without letting the people in the back know (i.e. dual IDG failure, with a failure of the standby buss) and I can't do it.
What about a loss of power to the EFIS displays, so even if the IRS and GPS were functional they wouldn't be any use to steer by. I remember a 757 that happened to in Europe many years ago, but I forget the cause. They don't like heat, an equipment cooling failure could take them out.
Quoting fr8mech (Reply 19): I'm calling BS on a story that was designed to make a point about electronics on aircraft.
Maybe it was the iPad the report mentioned they navigated with that caused the problems.
The glass isn't half empty, or half full, it's twice as big as it needs to be.
25 longhauler: That's not a DC-8 .... VC-10 maybe?
26 fr8mech: I thought about that. In fact, if this is true, it's the most likely scenario. I believe the 4 screens all live on at least 3 different busses. Very
27 Jetlagged: But it has happened to at least one 757. That wasn't over an ocean so radio navigation was still possible. I forget the cause, but it was back when g
28 Max Q: As unlikely as that is you would still have a course to steer by referring to the legs page of the FMC computer. And if ADF is fitted you can steer t
29 rfields5421: While I agree in principle - what about airline SOP. At which point does United SOP consider the navigation system unreliable. When one IRS disagrees
30 zeke: What about the QF 744 incident into BKK ? A fault with the water drain in the galley caused water to go over the avionics, getting rid basically all
31 fr8mech: I'm not saying it can't happen, I'm saying that it's highly unlikely. And, it would require multiple failures. And, chances are the folks in the back
32 rfields5421: The more I think about this, the more I'm inclined to put this into the urban legend category. Not for any of the valid reasons both against or for t
33 tdscanuck: Didn't that just take down the AC buses? They would have still had hot battery, capt DC, and standby. That would give you some (though certainly not
34 zeke: UA only do 4 flights a day from SFO to HNL, it shuld be easy to check with flight aware to see if the 124 odd flights for teh month made it to HNL. U
35 KELPkid: Seems like such a failure would be reportable to the FAA, NTSB, or both...that's been my thoughts throughout the day. In which case publicly availabl
36 longhauler: Not to mention ... on the inside, this alleged event would be HUGE, and every pilot of every B757/767 would be informed and warned ... and we haven't
37 COSPN: I dont think you have to be "pilot-trained" to notice the plane has done a 180 and heading back east...
38 zeke: Can I ask then what you were told about the S7 airlines 767 incident in October that had a similar loss of navigation and diverted Venice ? I suspect
39 Starlionblue: True. However most people would not notice.