From the ECDIS course I took the overlay was only to avoid gross errors. To update the DR a fix is taken, accepted and then the DR is automatically updated.
Any combination of visual or radar can be used.
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Navigating visually and taking and plotting fixes are cognitively very different tasks. Having to shift back and forth between the two tasks in a high workload situation is difficult and inefficient as it involves reloading short term memory.
Keeping a nav plot without any other duties is relativity easy. The time between fixes can be spent studying the chart, radar and identifying aids. Familiarity with the area makes it easier but it’s not really required.
Fixes can be taken and plotted with no rush, a good DR can be maintained. There is no rush to return one’s attention forward.
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That landing was successful because most of the people lived through it. The crew kinda like Sullenberger had to make a major withdrawal from their experience account.
My nav experience was in the 70’s with mainly visual compass bearings backed up by a great radar nav team in the CIC. We were overkill in nav information compared to what was really needed. A decent visual and radar nav team could be done these days with probably 5 men not counting the guy driving. They could advise that guy of turn points while he kept the ship on a track with a bearing essentially ahead.
I had San Diego arriving and departing in a pocket notebook with the 359 deg true range at the entrance with the turn point as a beam bearing, the next leg was a steer to bearing on a landmark and so on, pretty much as I imagined how you guys did it. When I conned the ship in and out the nav team just kept a record while I kept the ship on track of fair water. Not really the Navy way but it worked smoothly when I could get away with it!
The task of controlling the aircraft, normally done by one person, was divided up amongst the crew…and a passenger.
Is this information about help from a passenger in controlling the aircraft from Captain Sullenberger’s book? I haven’t seen it anywhere else.
Not Sully, the Sioux City accident, UA232
As luck would have it, Dennis E. Fitch, a United DC-10 flight instructor was aboard. He offered to help the crew, who had found that the throttles for the two intact engines still responded.
Maybe technically not a passenger but not part of the flight crew…
Got it. I hadn’t gone back far enough in the posts to see that your reference was to a different event.
GPS always scheduled to stop working every solar year ( 11 years apart)
we got lucky last time as the big flares from the sun went out into space and not our way, prior one we did get hit.
Who gets the space forecast before doing a DP job so you know?
I don’t think the issue is “what if the GPS goes out”. It’s the fact that a good navigator should be using ECDIS and other similar tools not as a primary method but instead as a secondary method for a cross-check.
It’s actually easier to do that way but it take more time to learn. Plotting on paper charts or using an ECDIS are methods that simplify the problem of navigation. The brain can be trained to simplify the visual to extract the information required but it takes practice. Practice that mates with their head buried in the ECDIS are not getting.
As the operator of a small vessel, with electronics probably an order of magnitude less reliable than the ones most of you have, I can’t say enough about keeping all your resources in view and comparing. Putting the radar on the plotter as an overlay is just one thing, but it provides pretty much instant display if the heading source or GPS go kooka-wakka. Its also a good way to spot a rain squall trying to sneak up on you!
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