From Behind the Cockpit Door...Part 2 (Airlines in general)

Member Name: flyboy27

Product:	Airlines in general
Date:	20/07/02 (409 review reads)
Rating:

Advantages: Safe, Fast, Efficient

Disadvantages: Sometimes late

Things that go bump in the night…or the day.

We left off somewhere back at the gate. Let’s see here…Preflight Checklist, Before Starting Engines Checklist, paperwork, I plugged in my headset, coffee with cream – ready to roll.

As the engines are started and the aircraft taxies out for takeoff you’ll notice a number of sights and sounds. So… let’s make you all experts. After all, the sweet old lady sitting next to you appears to be a little nervous and could use some reassurance from someone with your newfound wealth of knowledge.

ENGINE START - The air used to start the engines is normally the same air that supplies the air conditioning system. Since that air supply typically can only supply one source at a time the air conditioning shuts off during engine start. That’s why you may notice a change in the sound of the air within the cabin during that time. It might get a shade stuffy for a minute, too. Once the engines are started the air conditioning gets it’s air from the engines themselves.

TAXIING – Ever try to drive a shopping center? My office (the Boeing 767-300) is 176” long (53.87 meters) with a wingspan of 156” (47.57 meters). I have to plan every turn on the ground because the main landing gear sits so far (about 87’ or 25 meters) behind me. Cutting one turn too sharply can put the mains in the mud and ruin everyone’s day.

The jet blast behind a big jet is phenomenal so we try to keep our power down especially around the gate areas. The idea is not to blow over the baggage carts, busses, or catering trucks (although, after reading a few airline meal ops that might not be all bad…). This rig weighs over 400,000 lbs (181,437 kg) and it takes a great deal of thrust to move it let alone make it fly. The 747 and 777 are even bigger and we’ve seen demo tapes that show a big jet blowing a truck a couple hundred meters. Th
e ground personnel also get some serious “stay way back” training.

During our taxi out, the final takeoff weight, center of gravity, control trim settings, etc. are transmitted to the aircraft onboard computers. We check it against the planned numbers since typically the final numbers are different depending upon how many people overslept or got caught in traffic. We cross-check everything right down to runway length and takeoff conditions and when I’m happy with what I see, we’re good to go. At the same time we’re doing our pre-takeoff systems checks and reconfirming our planned flight clearance.

Meanwhile back at the ranch…what’s happening on your side of the cockpit door? The flight attendant announcement or recording…”Ladies and Gentlemen to fasten your seatbelt, insert blah, blah, blah”. Okay, so maybe you don’t exactly listen to this whole speech every time. In all honesty, if you can’t figure out how the seatbelt works I don’t think this article will help much either. There are a couple important things I would like to point out that aren’t mentioned but really important to know.

An emergency evacuation is extremely rare. The aircraft emergency exit lights can illuminate when either turned on or come on automatically during certain types of power failures. Just because they’re “on” does not mean there is a need to evacuate. With that in mind let’s move forward a bit. Here’s airliner trivia 101. The emergency exit lights usually have there own self-contained power sources…they don’t work like Christmas lights. Even if the airplane were to break (heaven forbid) into two pieces the lights operate independently and would still work.

Here’s a more non-trivial fact I want you all to store in your memory banks. Almost all aircraft now have a floor emergency lighting system. It’s intention (dur
ing an emergency evacuation) is to direct you to the exit if the cabin lighting has failed or the cabin fills with smoke. Next time you are on an airplane take a look at the spacing between those floor lights. The spacing of the floor lights gets closer together when you are adjacent an emergency exit. Also, if you are still walking down the aisle you’ll feel a notch or bump on the overhead bin right at the emergency exit.

Back to what’s happening on my side of door.

FLAPS - During taxi-out the flaps are extended for takeoff. Take a look at both the front and back of the wing the next time you fly. On Boeing aircraft as well as most others you’ll notice devices extending on either side of the wing. The size of the wing literally increases when leading and trailing edge flaps extend. This allows the airplane to fly at a slower speed thus requiring less runway distance. A bigger wing equals more lift. The flaps never extend fully for takeoff as they do for landing. The last notch of “flaps down” simply creates too much drag to be effective for takeoff. Although payload is a factor in determining takeoff flap settings, the airport elevation, runway length, and the obstruction height of our initial flight path are often even bigger players.

TAKE OFF POWER – why is this airplane using so much runway for takeoff? Because it can. The misconception that an airplane sets maximum power for takeoff is just that – a misconception. We use the extra runway simply because we have it available and we’d rather not toast the engines. Don’t get scared and don’t let me lose you here. The airplane typically uses a standard power setting (less than maximum) for takeoff.

Here’s the good news. The engines hanging off those wings are monstrous and max power simply isn’t necessary. It’s a very exact science. At standard power, the airplane can fail one engine at it’s most
critical point and still takeoff, climb and clear obstacles on it’s remaining engine. This is referred to as the infamous “V1 cut” and is an intricate part of our training and certification.

In the event of an engine failure, I have to keep the aircraft within a specific distance of an imaginary line extending from the runway centerline and within an exact set of speed and altitude parameters. Our simulators, which run about 12-15 million dollars a pop, are used to track our exact actions, inputs, and flight paths. Those who can’t meet the criteria are welcome to apply at McDonald’s. Nobody squeaks through this program.

Back to takeoff power – Why not just use maximum thrust? Can you say “Space Shuttle”? Actually, standard power isn’t really that far from max and we are required to use max in some cases i.e. wet or contaminated runways, possible windshear in the area, etc. - all things that we consider less than ideal conditions. The truth is, max thrust is hard on the engines and seriously limits their lifespan.

Ahh – airborne at last. Next episode we’ll talk about the flight itself, turbulence, maybe a little navigation and air traffic control. Thanks for your input. Captain Tom

ADDITIONAL REMARKS

This review is probably a bit misplaced as it is more a statement of facts than it is an “op” or opinion.

Please allow me to share a brief background of my qualifications. I have a degree in Aeronautical Science, a flight engineer certification, an Airline Transport Pilot license with seven heavy aircraft type certifications, and 25 years of flying experience.

I have written numerous aviation-safety related articles for industry journals as well as published pilot study guides for Boeing aircraft.

I recently began participating with DooYoo as a diversion away from flying which is why my first few ops are regarding
my play-toys… then I ran into the Airlines category and started reading. The first article I read was “crowned” and referred to by some readers as brilliant. It was actually extremely inaccurate. A subsequent article (also crowned) with rave reviews was more researched but also required correction – so I thought I’d set the record straight.

I simply wish to give those nervous or curious flyers out there a more knowledgeable perspective.

To those who are unhappy with the segmented approach to my airline entries please bear with me and consider the following.

My cup runneth over. I am a full time airline captain, a father of three young children, volunteer as a police officer for my community, presently chair our Pilot Professional Standards Committee, and work as a communications officer for my union.
I’ll sleep when I’m dead – in the meantime I’ll make additions when I can. Notoriety, fame, or DooYoo miles are not my goals here. The goal is a little escape with a bit of light reading and sharing ops with good natured DooYoo’ers. So be easy on the old man.

To those of you who have benefited from these segments – Mission Accomplished! - Thank you for your kind words.

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