Aug 27, 2008

A Day in the Life (37) Let's Do It Again.

A description of a typical day’s flight from Montreal to Vancouver and return - as a backdrop for a detailed, non-technical description of what an airline pilot does. (check left hand column for series index).

Time: CYVR Departure minus 0H15

A quick glance through the log book - no issues. Good.

Then it’s once more around the flight deck panels, assuring all the switches are properly set for another departure. The airplane arrived recently from Edmonton so we don’t have any “first flight of the day” checks. Also good.

We finish up the procedures then F/O Paula hands me the datalink printout of our IFR clearance. I read it in conjunction with my SID chart, brief our departure plan with her, double checking the entries in the flight computers. Even more quickly than in Montreal this morning, the whole procedure is complete and now I again take a moment to welcome the passengers on board, giving them a brief heads up on the snow storm in Montreal. “For those of you who are permanent residences of Vancouver, the white stuff you’ll see in Montreal is called snow. For those Montrealers on board heading home, it’s just a regular day with gusty winds and three meter snow drifts… Welcome to Canada in December.”

We’ve been keeping in touch with our dispatcher and load agent. In normal circumstances we use an average weight for each passenger and each piece of luggage in determining our takeoff weight. Then we track fuel to the nearest hundred kilos because we can, being careful to stay within the legally allowed limit. Today we are counting the males, females and children and using those more accurately averaged weights to hopefully gain room for a few more kilos of fuel.

The Shell driver is standing by in the flight deck as our final load numbers come in over the datalink. We can squeeze in ten more minutes of fuel, approximately 400 kilos. He scoots out to squirt that into our center tank. It’ll be almost full now. Our flight plan gives us enough fuel to fly to Montreal, hold for twenty minutes, then divert to Toronto and land with a half-hour of emergency fuel on board. That’s the law. We also have another ten minutes of contingency fuel that we may or may not need enroute. If we can save it along the way, then we could decide to use that holding over Montreal in case it would make the difference between landing or diverting to Toronto. Working with these relatively skimpy fuel reserves in bad weather causes a special kind of stress that has earned its own nickname. It’s called Pucker Factor - named for its effect on a certain anatomically sensitive area of the human body.

The re-fueler calls on the interphone to give us the number of liters he’s loaded. F/O Paula adds that to her notes to make all the fuel crosschecks work out. I see that our weight at pushback is at the exact legal maximum for this aircraft. In that number is 400 kg. for taxiing. I tell myself that if the tanks should be sloshing around, giving slightly variable flight deck readouts and we just happen to take off with say, 200 of those taxi kilos still in the tanks, would anyone notice? Only if we end up on the six o’clock news*.

The cabin door slams shut behind me and the lead ramp agent confirms that the refueller has closed up the wing panel and moved his truck out of the way, as he calls up on the intercom:

“Ready for pushback…”

“Standby,” I reply and nod to F/O Paula who’s already negotiating our pushback clearance with Vancouver ground control.

I flip the parking brake off and note the time. Another on sked departure.

Time: CYVR Departure minus 0H00


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* The wings won’t fall off if we are heavier than our maximum take-off weight. Obivously if we were seriously over it our performance would be degraded and it could have long-term implications on the stress in the airframe. However the certificate of airworthiness would be technically voided, and that’s a really bad thing if you end up in court for any reason.

I remember early in my career an accident involving an Air Canada DC-9 that over-ran the end of the runway in Toronto after a rejected takeoff. The aircraft slid into a ravine and was destroyed and a couple of passengers were injured. The headline on the CBC radio news shortly after started out with the dire-toned information that the aircraft was OVERLOADED at takeoff! Listening to the details within the story, it turned out that the plane indeed was over it’s legally-allowed weight by two hundred pounds. They neglected to mention that the total weight of the aircraft was 108,000 lbs.! And that these ‘standard averages’ had been used to determine all this. What nonsense. And the slight weight deviance proved to be a total red-herring.

Perhaps one day our actual weights of all passengers and bags will be accurately determined (and charged by the kilo?), but until then, there is this ongoing vigilance over averaging and guesstimating and when it is okay, and when it’s not.

7 comments:

Millz said...

I have truly enjoyed reading this series!

Do some large aircraft have sensors to determine the exact weight, maybe something in the wheel struts?

Aluwings said...

Many ideas have been discussed but nothing has been invented that would be reliably accurate in all situations. A system based on landing gear strain would be mis-led by snow and ice on the airplane for example. Other ideas have included sensors in the pavement, etc... But nothing yet has met the cost/benefit cutoff point to be implemented.

Aviatrix said...

"It will fly overweight, but it sure as hell won't fly without fuel."

The further north you get and the further into winter, the less likely it is that recorded ullage in the paperwork is really empty space in the fuel tanks.

Dan said...

A couple years back I had the roughest winter ride into Montreal ever on a Delta flight from Cincinnati. I remember the flight attendant started the trip by announcing how excited she was to be flying into Montreal for the first time ever...

It was November, and it was only a light snowfall on the ground, but for some reason the final approach (last 5-6 minutes) was brutal up there in the dark snowy clouds. I think I was on a CRJ, so we were bouncing everywhere, dropping randomly and rolling left and right. I seem to recall seeing the ground lights only about 5 or 6 seconds before we touched the tarmac.

But this poor flight attendant was so panicked during approach that she literally assumed a crash position on the floor of the galley where the food cart and supplies are kept... I remember the passenger in row one went and picked her up and brought her to sit next to him in the empty seat, tied her seatbelt on her and held her hand for the landing!

I guess no amount of training or flight experience can always guarantee that the crew is going to keep a cool head during stressful situations!

Still not sure how the air could have been so rough up there, when it was such a nice light snowfall Montreal night on the ground...

Aluwings said...

Dan, that sounds like quite the "ride!" Wow. It isn't unusual to have very different weather just above the surface. Often a weather front will lie just above the approach to Montreal and the large difference in wind speed and direction and temperature can kick off some wild turbulence - meanwhile just giving "peaceful" snow below.

I've seen take-offs from YUL where the surface wind was only about 20 to 30 knots, but above 500 feet it was well over 60 knots! That would rip a few shingles off if it touched down.

gerg said...

Correct me if I'm wrong, but don't you need 45 minutes reserve fuel while flying IFR?

Aluwings said...

Hey Gerg, thanks for the question. I believe 45 minutes is still the reg. for non-commercial IFR. But in Canada (and I believe in the US?), airlines have a 30 minute requirement (here's an excerpt from the CAR:)

Fuel Requirements

705.25 (1) Subject to subsection (2), no air operator shall authorize a flight and no person shall commence a flight unless the aircraft

(a) when operating in VFR flight, carries sufficient fuel to fly to the destination aerodrome and thereafter to fly for 45 minutes at normal cruising speed;

(b) when operating in IFR flight on designated routes or over designated areas as defined in the Commercial Air Service Standards, carries an enroute fuel reserve of five per cent of the fuel required to fly to the destination aerodrome; and

(c) when operating in IFR flight, except when complying with the Safety Criteria for Approval of Extended Range Twin-engine Operations (ETOPS) Manual, carries sufficient fuel to allow the aircraft

(i) to descend at any point along the route to the lower of

(A) the one-engine-inoperative service ceiling, or

(B) 10,000 feet ASL,

(ii) to cruise at the altitude referred to in subparagraph (i) to a suitable aerodrome,

(iii) to conduct an approach and a missed approach, and

(iv) to hold for 30 minutes at an altitude of 1,500 feet above the elevation of the aerodrome selected in accordance with subparagraph (ii).

(2) An air operator may be authorized in an air operator certificate to reduce the enroute fuel reserve required by paragraph (1)(b) where the air operator complies with the Commercial Air Service Standards.