Friday, May 30, 2008

Wind Stream, Part 2

Position: Abeam YZP (Sandspit)
Destination: Anchorage
Groundspeed: 362 mph (314 kts)
Winds aloft: on the nose at 155 mph (135 kts)

Over the neck of Idaho, my dispatcher sent me a message concerning turbulence over British Columbia along our flight planned route. He suggested a new route along the west coast of British Columbia. Instinctively, I knew this would happen before we left Las Vegas. It is the way of things up here.

So now we are in the headwinds. They are perfectly aligned with the Fi-Fi's nose cone. Not even one quarter of a degree off the center axis. Remember that extra taxi fuel I skillfully wrung out of the flight plan? Well, now we need it for unknown contingencies.

There was a time when the captain was allowed to burn into the landing reserve fuel and if it was not too egregious, then, as the old saying goes: No harm, no foul. The thinking back then was that reserve fuel was considered as... reserve. However, if the burn into the reserve was on the border of being idiotic, then a report to the Chief Pilot was filed with a probable butt chewing as the result. In these contemporary times when everyone knows more than the captain, burning into the landing reserve is considered an emergency and it is mandatory to treat it as such. Ridiculous, I say...

On the flip side, airline management does not want the aircraft to land with any extra fuel because it costs money to carry fuel weight. Hence the landing fuel targets that are all the rage nowadays at all the carriers.

We are going to miss that target if I do not come up with a solution to this headwind. According to the winds aloft forecast, the headwind component begins to rotate to the left of the nose in 200 miles. My instinct tells me that will be the case. Also, I think we need to track toward the eastern edge of the forecast wind stream and try to find lower wind velocities. This will add a few more miles but could easily create more fuel-in-tanks at the next check point. Changing altitude is not an option... Lower burns more fuel and higher is in the ozone no-fly altitudes for this time of the year.

Vancouver ATC cleared us to turn toward ICK radio beacon, about 20 degrees to the right. Fi-Fi did not like it. She had no wind speeds to chew on over there, so she thought we were going to be below our landing fuel target. Take it easy, Fi-Fi... It will be OK. Worst case scenario; we will have to land in IFR conditions at Juneau for more fuel. Not if I can help it, though. Our Anchorage ETA is already one hour behind scheduled arrival time, so a few more minutes will not matter in the big picture. The co-pilot suggested we give Fi-Fi a lower cost index for the nav computers to ponder upon. That is a really good idea. Too bad I did not think of it. The "cost index" is a $100 word for a $10 term, i.e., it is a ratio of the cost of time divided by the cost of fuel. In other words, a cost index of zero provides cruise speed and descent planning for maximum range. OK, enough of that...

I plugged in a big fat zero in the performance data which bumped up the landing fuel by 400 pounds. Next, I cleaned out all the flight plan wind data and put in wag winds. Our new and improved fuel on board at Anchorage is the minimum required by the airline. Things are looking better.

Top of descent

We found the eastern edge of the wind stream and were able to get out of the strong headwinds. The landing fuel is still at the minimum required. I reminded the co-pilot, who is flying this leg, that he needs to be very careful about energy planning on the approach. A go around will necessitate burning into the reserve fuel which is considered a no-no. Unlike the 737 days, we cannot massage the fuel figures with our #2 pencils. Fi-Fi automatically sends the fuel-on-board to Mother. Can't trust those rascally pilots, you know.

After clearing it with the co-pilot, I requested a short approach. Anchorage ATC vectored us to the runway outer marker and turned us loose. We saved about 25 miles of ground track. The co-pilot made a nice landing and turned her over to me at taxi speed. I told him to shut down number two engine for the trip to the gate.

The rampers plugged in the ground power; I got the green light on the overhead and shut down number one after 6 hours 35 minutes. We flew to the very end of the A319's fuel range; reserve fuel was literally waiting in the wings.

No admission of guilt paperwork for me tonight!









20 comments:

Lachlan said...

Dave,
Reading your post would suggest that the 'landing fuel' is not actually a physical measurement, but more a guess by the computers?.. A guess that can be influenced by a few key presses on the MCDU to keep you out of remedial training?

Fantastic two part post!!
Lachlan.

Smurfjet said...

When using one engine for taxi, do you alternate between #1 and #2 to balance 'operating life'? Will that create a situation where one engine will need maintenance sooner than the other?
Do you log engine hours separately?

Bah I just realized Fi-Fi is a wonder jet and can probably figure all that out hehe!

dave said...

lachlan- the nav computers estimate FOB during the entire flight, but the optical disk emails Mother with the actual FOB at the gate. There is no way for the pilots to change that and if they did and were caught... Yikes!

smurfjet- we taxi on #1 only because of the hydraulic system plumbing; #2 causes an emergency PTU to run and it is loud. It annoys the passengers in the back.

Keith said...

A comment to your comment, dave. The PTU is activated when only the number 2 engine is running, but isn't the #2 engine always started first, thus activating the PTU until the #1 starts as well? Is it possible to start the #1 first to avoid activating the PTU?

Anonymous said...

interesting double post. Thanks!

dave said...

keith- we always start #1 first unless there is a reason to start #2 first, i.e., something in the way like an air cart or an air stair, etc.

Joel P. said...

Great work Capt. Dave!

Anonymous said...

It usually happens to me on the last leg of the last day of a 4-day trip. Unforecast winds are 90 knots on the nose and my last ride home leaves 15 minutes after scheduled arrival time. Then approach control in ORD suddenly gets friendly and cuts us into sequence a mile short of FAF.
Wow!
Dragging the rollerboard at supersonic speeds across two deserted terminals helps to make it to the door on time. They haven't closed yet.. Double Wow!

Thanks Dave.

Tim Perkins said...

And some folks think that machines will fly machines someday...

Thank goodness for the human touch.

Noella said...

The average happy camper (or nervous flyer) in the back has no idea of just how much intelligence, painstaking planning and a good dose of common sense takes place on the flightdeck!

Another awesome story and insight, thanks Dave. Keep safe.

Noella said...

Ha ha ha! The word verification of muddled letters for that comment was 'gaswell'!

Rich said...

..."in these contemporary times, when EVERYONE knows more than the captain"...

Point well taken, Captain, with all the expertise and experience shown in this article.

If they just would listen to you...

Anonymous said...

Thanks for a fascinating story, Dave. Keep up the great work, and have a safe trip back!

Drew said...

Dave,
Great post. I always eagerly await your blog updates.

Biff von Mises said...

I'm surprised that the company would allow the Cost Index to be modified. I'd think some bean counter would want a fixed number for the CI, which could affect the bottom line.

I'm a big fan of the blog. I found it by doing research on RC-12 weight and Balance.

Biff

Aviatrix said...

Nice one.

It's not like bush flying where you can carry around a few gallons all day that no one knows about. it's not in the weight and balance; it's not in the OFP; but it's there in the tanks when the planned fuel burn is gone and the reserve is gone.

Anonymous said...

riveting prose!

since reading this blog, i always thank the pilots when i leave a plane for their dedication to training and their hard work to keep us safe. i am amazed how few people thank them for a safe flight.

Jen said...

So, you can't use your reserve for waiting on the ramp, you can't use it for go-around, you can't use it for an unexpected headwind... Exactly when are you allowed to use it?

I can understand not wanting to make a practice of eating into your reserve, and I'm glad the airlines aren't using it as a way to pinch those pennies. But, it seems all that other stuff seems like WHY you carry reserve in the first place.

Johnny said...

Hi Dave,
I am enrolling with an FTO and hope to have my wings in due course. Your blog is both witty and fascinating, and full of useful information for an aspiring airline pilot. Wish I could pull gear for you!
Thank you, and stay safe!

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