Air India at JFK...gone with the wind..!?
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Did they always have the raw data ILS available? If yes the story should be much less thrilling.
A comment about climbing to save gas while holding - the gas you burn to climb is often greater than you’ll save at the higher altitudes. Performance charts show a savings of of roughly 120-200 lbs/hr per hour by climbing from 5,000to 10,000. That’s roughly 25-40 lbs/hr saved for each 1000’ of climb. Based on simple observations from enroute climbs the fuel burned (300-400 lbs for 2000’??) to move the airplane 2000’ higher would take hours and hours to recuperate.
The old thinking of staying high to ‘save gas’ in holding is frequently inappropriate. A 777-300 most efficient holding altitude is around 15,000’. Other jets are similar.
A comment about climbing to save gas while holding - the gas you burn to climb is often greater than you’ll save at the higher altitudes. Performance charts show a savings of of roughly 120-200 lbs/hr per hour by climbing from 5,000to 10,000. That’s roughly 25-40 lbs/hr saved for each 1000’ of climb. Based on simple observations from enroute climbs the fuel burned (300-400 lbs for 2000’??) to move the airplane 2000’ higher would take hours and hours to recuperate.
The old thinking of staying high to ‘save gas’ in holding is frequently inappropriate. A 777-300 most efficient holding altitude is around 15,000’. Other jets are similar.
As a rule of thumb, we used to reckon (on the DC-10) that if you were contemplating a 2,000 foot step climb, you would have to be up there for at least one hour to actually save any fuel. Incidentally, I was based at JFK for 3 years and I think that the crew and ATC both did a good job.
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JW - I’ve timed the fuel flow before and after the climb, checked the performance pages, noted the average fuel burn during the climb, timed the climb, etc.
I estinated the time to payoff is about 45 minutes. So we’re in the same ball park.
I estinated the time to payoff is about 45 minutes. So we’re in the same ball park.
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Did they always have the raw data ILS available? If yes the story should be much less thrilling.
1. They made a comment along the lines that it would not “lock on”, and
2. They reported 2 RA’s failed.
Join those dots.
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Quite disturbing.
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If anyone cares: The webtrak clearly showed they did a step down approach with level-offs consistent with an LNAV approach.
(webtrak with noise monitors showing radar data of the new york area: http://webtrak5.bksv.com/panynj)
What he probably meant they flew a LNAV/VNAV approach crosschecking with the ILS readings.
(webtrak with noise monitors showing radar data of the new york area: http://webtrak5.bksv.com/panynj)
What he probably meant they flew a LNAV/VNAV approach crosschecking with the ILS readings.
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The low cloud ceiling was the issue and thats why they were apparently unable to conduct an ILS approach down to landing. Not a question of raw data but the fact that with the low ceilings they needed to conduct an auto land and with the failures on board they were unable to do that and hence were looking for a place to approach where the ceiling was better so that they could possibly sight the runway at minima and continue to a safe landing.
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What he probably meant they flew a LNAV/VNAV approach crosschecking with the ILS readings.
And there is nothing wrong with that (to CAT I) providing the raw data is monitored.
Now, maybe I’m being biased by what I would do in that circumstance, because that is certainly what I would do in that failure scenario!
ILS in LNAV/VNAV will get you lower than any other RNAV approach. Yes, you could fly it manually in raw data, but why?
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Many of the GA crowd has SBAS RNAV, which gets them LPV minimums. LPV is usually the same as ILS CAT I to a given runway. It is with 4R at KJFK, but not with 4R at KEWR.
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What do we have?
What do we need?
If something else IS needed, How do we get it?
A raw data, hand flown ILS seems the consensus here, so nothing else was “needed”, though I am sure it was wanted.
What do we need?
If something else IS needed, How do we get it?
A raw data, hand flown ILS seems the consensus here, so nothing else was “needed”, though I am sure it was wanted.
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Power failure?
According to the FAA MMEL you can do 180 minute ETOPS on the 777 with an inop APU generator with both engine IDG's working and backup AC checked before every flight. Some of this MEL stuff is grandfathered from the 767 ETOPS certification three decades ago.
I've never been comfortable with generator inop dispatch on an ETOPS twin but there is indeed MEL relief in many cases.
I too am curious whether the APU was dispatched inop or was unable to start due to some electrical fault? Or was an IDG dispatched inop and some glitch propagated through the electrical system when a breaker opened or failed to close with a bus loss on the first approach?
Years ago I took a non-ETOPS 757 with an IDG inop. There was an unusual pause before the legacy CRT screens came back up after the first engine start, maybe some relay clicked out of sequence. Airborne the heading bug on the EHSI became unsynced with the HDG window on the MCP. We were in VNAV and it didn't look right so we tried FLCH and then both lights were illuminated. It was the old days and a short leg so we popped off the autopilot and flew the plane to the destination without the benefit of autoflight (oh, the horror
). On the ground the mechanics removed all power from the plane and restarted, it seemed to reboot the FCC's and we handed the aircraft to another crew.
I've never been comfortable with generator inop dispatch on an ETOPS twin but there is indeed MEL relief in many cases.
I too am curious whether the APU was dispatched inop or was unable to start due to some electrical fault? Or was an IDG dispatched inop and some glitch propagated through the electrical system when a breaker opened or failed to close with a bus loss on the first approach?
Years ago I took a non-ETOPS 757 with an IDG inop. There was an unusual pause before the legacy CRT screens came back up after the first engine start, maybe some relay clicked out of sequence. Airborne the heading bug on the EHSI became unsynced with the HDG window on the MCP. We were in VNAV and it didn't look right so we tried FLCH and then both lights were illuminated. It was the old days and a short leg so we popped off the autopilot and flew the plane to the destination without the benefit of autoflight (oh, the horror
). On the ground the mechanics removed all power from the plane and restarted, it seemed to reboot the FCC's and we handed the aircraft to another crew.