Wednesday, April 14, 2010

Aight, let's go through our checklist in painful and boring detail :)
Scroll down one post for an example of the checklist we use.

Ima skip some of the ones that are obvious to me, but if you have any questions I'll be happy to blather on about any missed items.

1. customs/canpass - did we do the paperwork before attempting a crossborder flight? This is all done electronically now when we go to the US, via the Eapis system. On the way back to Canada, we just make a phone call to CANPASS.

2. oxygen system - we check our masks to make sure they are plugged in and there is pressure in the lines - there is a little indicator in each mask that shows a green stripe if there is pressure in the line, and a red stripe if there is no pressure. Oxygen control valves are switches that dump the emergency oxygen masks in the passenger cabin if we want to completely freak them out, or if the cabin altitude exceeds 13,000'.

3. circuit breakers all in, switches switched appropriately - we double-check these because our maintenance guys could have done routine maintenance on the airplane and left c/b's pulled or switches in unusual positions as part of their maintenance checks. They are, ahem, strongly encouraged to leave the cockpit as they found it, but as we all know, sometimes stuff happens.

4. we fire up our standby attitude indicator (we actually have 2 standby AI's) to make sure it has spun up before flight. It has its own little battery pack and doesn't need main bus power or main battery power to spool up.

5. If we are doing a ground-power-unit (GPU / battery cart) start, then we leave our generators off, but if we are doing an engine start from our own battery we leave our gens on - that way once we start one engine, the generator on it will help provide electrical power to start the second engine - so much so, that a GPU or cross-generator start only counts as 1/3 of a battery start for logging purposes.

6. Battery emer check - we check that our vital systems will still be powered by the emergency battery bus in the event of a complete electrical failure. If we somehow were to lose our main electrical system, the emergency battery bus will power our #1 communications radio, our #2 navigation radio, and the copilot's HSI (navigation thingy), along with a few cockpit lights. That means that if we lose electrics, the copilot will have control of the plane as the Captain's HSI will be toast.

7. We check our various warning systems - that's an easy one - there's a circular switch with about a dozen positions we rotate to in order to check all our various warning systems, like thrust reversers, landing gear lights, windshield bleed air heat, engine fire indicators, TCAS etc. That means the cockpit gets lit up with bells and lights and buzzers for a few minutes, but again it's important to make sure the bells and lights and buzzers will operate correctly if they need to.

8. We check our fuel crossfeed valves and indicators to make sure we can use fuel from either tank to feed either engine. Our fuel burns are pretty amazingly even on both engines, and we generally don't have to crossfeed from one tank to another, but if we were to lose an engine and have to fly around for a while before landing, it's nice to know we can burn fuel out of either tank to feed the remaining fan.

9. Inverters - we have dual inverters (they change the electricity provided by our generators from DC to AC for those systems that run on AC power), and we make sure they are both working - one inverter can easily provide enough power for the entire airplane, but we have two of them as a backup and we make sure both are happy and purring before we blast off.

10. Pressurization and environmental - basically we dial in our expected cruise altitude into the pressurization system, and we turn the air conditioning on if it's hot outside.

11. Trim / Flaps - we normally take off with 15 degrees of flap unless we are operating out of an airport that has a high altitude about sea level. We set the trim depending on the aircraft load - if we have some hefty passengers sitting up front, we'll trim the aircraft to be nose-up a little bit, so we don't have to reef on the controls as hard to pitch upward to take off.

12. CVR - we press a little green button on the cockpit voice recorder and if a little green light goes on in 5 seconds, it passes the test. If it doesn't go on, we get it fixed before flying. That's about all I know on that one.

13. Autopilot - we run it through a bunch of tests for the first flight of the day, but for all other flights that day we can do a quick-test by pressing a little red button and listening for the "you passed the test" buzzer.

14. Atis / GPS / Data / Takeoff Briefing / clocks and bugs - We find out the weather, write it down, find out our clearance, write it down, then enter our flight plan into our GPS. We then calculate our various speeds and thrust settings using a book I made up a few years ago - those are based on our weight, the airport altitude about sea level, and the temperature on the ground. Modern jets will automatically calculate all that stuff, but we do it manually. In the checklist under "Before Takeoff" you'll see a little section called 'simplified takeoff data' - we can use those numbers if the aircraft falls under the conditions set out in the table, which is handy on quick turnarounds - the thrust settings and speeds in the quicknumbers are conservative, so if we wanted to be extra-anal, umm, I mean precise, we could still look up the exact numbers for our temp/weight/altitude etc in the big book.

15. Pax advisory / coffee - we flip on the "fasten seat belts and stop smoking" lights, and we hit the switch that heats the onboard coffee pot. This is very important for pilot and passenger caffeination.


You'll notice there's a little black line on the checklist after these checks. We can do all the previous items hours before the flight, but we don't go below the line until everyone is on board and the main cabin door is closed.

Once everyone is on board, we make sure the doors are all closed and locked (the "door unlocked" light will go out). We turn our avionics off in case we get a power spike from a bad GPU or generator during start, we turn off our air conditioning because it's a total power hog and we want to use all available power to spool up the engines quickly, we do a quick check of the engine instruments to make sure they look normal, then we pick an engine and hit the start button on it. We will then monitor the engine instruments to make sure we get oil pressure / fan rotation / fuel flow / engine temperature indications at the right times, and once the engine is idling nicely, we flip the switch that extends the speed brakes. Each engine has a hydraulic pump that can power all our hydraulic systems, and our speedbrakes are one of those systems. If the speedbrakes operate normally, we know that the hydraulic pump on the spinning engine is working. We alternate which engine we start in order to test each hydraulic pump every other leg. Once we ascertain everything is tick-boo with the spinning engine, we fire up the other fan.

Phew, I have writers cramp now so Ima take a break - I'll talk about the rest of the checklist in painful detail shortly. The funny thing is, it takes about 5 minutes to do all these checks once you are familiar with the plane, far less time than it took me to write about them, or for you to read about them. Good thing too, otherwise we'd never get off the ground :)

7 comments:

fche said...

"On the way back to Canada, we just make a phone call to CANPASS."

... and file an eapis departure report too, surely.

Sulako said...

yes.

Mogg said...

Why are DC generators still used, when alternators provide excellent power to weight ratios?

Sulako said...

Our generators are actually starter-generators - we use them for start, and once the engines spin up, the same hardware is used to generate power. Various systems on the aircraft use AC and various systems use DC, so there's a need for both kinds of current. I'm guessing that combining the starter/generators saves weight over having 2 different pieces of hardware to accomplish those tasks, but the ultimate answer to this question isn't for me to say, that's for whomever the engineer was who designed the system for Cessna.

Michael said...

Can you explain the logic behind the emergency battery bus powering the particular instruments that you listed?

I understand that it's important to know what is left working when the lights go out, just wondering why it's the HSI over on the right side that keeps ticking. More importantly, is it proper for the Captain to get the FO a cup of coffee to increase his/her level of "alertness" in just such a situation? :-D

Brian said...

Foot warmers? I mean, wear a pair of winter socks and use that energy elsewhere!

Seriously though, there's gotta be something I'm missing with regards to that.

Sulako said...

Michael: On the original Citation II's the Captain has an electrically-powered large Attitude Indicator, while the f/o has a small air-driven attitude indicator, identical to the one you'd find in the Cessna 172. That meant that in the event of a total electrical failure, the Captain's AI would lose power, but the f/o's would keep upright - the air-driven gyro doesn't need external power as long as there's air moving through the engines. Our Citation II has the large electrically-powered AI's on both sides, but that's an aftermarket mod. That being said, in our plane we have a C-172-style backup AI on the f/o's side in addition, so the copilot would have an easier time keeping straight and level than the Captain, who only has a good view of our tiny little emergency backup AI (even smaller than the 172-style one).

Brian: Footwarmers are just air vents down by your feet that we either open or close depending on how chilly it is - if we close them, the extra warm air goes to the windshield, and after cruising at high altitude for a few hours, the w/s gets pretty cold, so in an effort to prevent it fogging up, we generally redirect the airflow from our feet to the windshield as we descend. It's not bad - it usually gets warmer the more we descend so our feet don't freeze solid on a regular basis :)