Good Day folks,
I have several questions which I am dying to have answered.
1) This youtube video: YouTube - Boeing 747 landing at Hong Kong (http://www.youtube.com/watch?v=4syzzafl6C0) which is the closest I can ever get to the flight deck (after god-damned Osama decided to blow up the twin towers).
What is the first officer refering to when he calls out "1000, plus 11. 900, plus 10" something like that >>>>> scene 1:22 to approx 1:39
2) Where is the 'steering wheel' located; For the nosewheel, which the pilot uses to steer the aircraft on the ground?
3a) On average, what is the real-life N1 takeoff setting used by a 737-800. 65%?? I know it depends on a lot of factors like runway length, load, wind, etc.. But I just want to know an average percentage.
b) Then the next question, airliners DO NOT use 100% N1 for take off roll, correct?
c) If the 100% N1 is used for takeoff roll, then v1, vR, v2 will all be attained very quickly, and the pilot will easily overshoot the 250kt limit for <10000ft restriction. Is this true?
Thank You in advance. Best regards to the aviation community, which I have deep respect and admiration for.
Coffin Corner
1st Aug 2008, 18:44
1. He's calling out the altitude and the speed above Vref, so 1,000ft & +11kts
2. The nosewheel tiller is on the captain's left hand side, if the F/O has one it'll be on his right hand side, whether the F/O has one or not is type specific.
3a. No idea sorry, don't fly 737s
3b. Normally correct yes.
3c. No not true at all.
SNS3Guppy
17th Aug 2008, 10:40
What is the first officer refering to when he calls out "1000, plus 11. 900, plus 10" something like that >>>>> scene 1:22 to approx 1:39
2) Where is the 'steering wheel' located; For the nosewheel, which the pilot uses to steer the aircraft on the ground?
3a) On average, what is the real-life N1 takeoff setting used by a 737-800. 65%?? I know it depends on a lot of factors like runway length, load, wind, etc.. But I just want to know an average percentage.
b) Then the next question, airliners DO NOT use 100% N1 for take off roll, correct?
c) If the 100% N1 is used for takeoff roll, then v1, vR, v2 will all be attained very quickly, and the pilot will easily overshoot the 250kt limit for <10000ft restriction. Is this true?
Callouts in the cockpit are very standardized. During a precision approach, we use 1000' and 500' callouts, in which the pilot not flying will say "One thousand feet, Pitch three (degrees)." The flight engineer will add "Descent rate, eight hundred." The pilot flying will reply "checks."
This is important, several ways. The pilot not flying is complying with standard callouts that the pilot flying is expecting to hear, and providing not only a verbal marking of the time that particular point or altitude is passed,but the airplane condition...in this case, pitch. Some companies may add speed, as well. These are clues as to the health of the approach, and may be insights into an impending windshear. A pilot who is on the proper glidepath and at the proper airspeed but carrying too much power or pitch needs to determine the cause or the corrective action. If a correction is needed, such as the airspeed is off, the pilot not flying may say "airspeed," and the pilot flying will reply "correcting."
The exchange isn't just important to let the pilot flying know what's going on. He's glued to the instruments. He knows what's going on. It's creating an interaction between the two, a system of checks and balances. A pilot who calls "airspeed" may get no response. If he calls the deviation again, "airspeed," and gets no response, he may be forced to assume the other pilot is incapacitated...this challenge and response, this standard call and reply, is a tool to help catch that as early as possible.
Callouts are important clues. As I approach to flare, I'm still high in the air;it's a big airplane. But as the callouts reach 30', I reduce power to idle and begin my flare, and based on the cadence of the vertical callouts (50, 40, 30, 20...) I know the rate at which I should be flaring, and what to expect. It's a team effortin this respect.
Likewise, during an instrument approach, one pilot stays inside the cockpit on the gauges, flying. The other pilot divides his attention between outside, looking for the runway lights, and inside, monitoring the instruments. It's up to that monitoring pilot to notify the flying pilot when it's time to look up. Looking up at the wrong time can be very disorienting, as well as taking the pilot's attention away from the critical task of flying the airplane...teamwork and standard calls allow each crewmember to interact with any other crewmember in the company in exactly the same way, with expected, defined results.
Steering can be in various places. Some airplanes use rudder pedals to steer, some use small steering wheels or tillers. Some use one kind of steering up to a certain speed, then switch to another. We use the tiller at lower speeds,and have both nosewheel steering, steerable body gear, and also receive steering inputs through the rudder pedals, as well as aerodynamic steering from the rudder itself as speed increases. Some airplanes use steering tillers to hydraulically or electrically move the nosewheel, whereas others use hydraulic valves through the rudder pedals to do the same...and others use it through the brake pedals. The answer, then, depends on the airplane.
I don't know on the 737-800. Not all airplanes use N1...many use EPR as well, and turboprops don't use either...most use torque. 100% on a turbojet engine doesn't mean all the power, nor is it necessarily the absolute operating speed. It's a reference speed just to make power settings easier. The performance data for the airplane will take into account altitude, temperature, aircraft weight, and other factors in determining the takeoff power setting. Often it's a reduced setting based on theoretical factors, a system which allows the use of lower engine temperatures to extend engine life, while allowing a safe takeoff and climb.
Because 100% N1 by itself doesn't mean anything, neither do any of the incremental power settings below it or above it. 85%, for example isn't 85% of the total engine speed or power...just a reference number that the data spits out to use for takeoff. Most turbine engines operate in their peak efficiency at higher RPM's, with typical takeoff N1's around 90-95% or so...but again, that really depends on the aircraft and on the various takeoff factors.
Airlines use for a power setting whatever their data calls for...be that 100% or otherwise. Generally a reduced power setting is used where possible.
As for the last question, whether N1 is used or not is purely coincidence, as the number doesn't mean anything. The appropriate power setting, as calculated is used.
I think what you're asking is if the maximum power setting (which probably isn't 100% on any given day) is used, does the airplane accelerate quickly. If that's the question, then again it really depends on the airplane. We have about fifteen criteria that state when we must do a max power takeoff...otherwise we do reduced power. We never really accelerate quickly. The only exception is when we're empty...no people or cargo, and just repositioning the airplane...then it really gets up goes.
During the takeoff, power is applied to the takeoff setting, and the various speeds called out. The airplane is rotated at it's pre-designated speed and climbed at an angle that uses "V2" plus ten knots, using the predetermined power setting. At a thousand feet above the field elevation, power is reduced (usually...sometimes increased, depending on the situation) to the climb power setting. This is for noise abatement. We continue the climb at V2 plus 10 knots until 3,000' above the field elevation, controlling our airspeed with pitch...pitch up more as needed to prevent speed from increasing. (up to 18 degrees of pitch for us...if we need to control speed any more, we start reducing power, at that point).
At three thousand feet, we pitch nose down to reduce our rate of climb to 500 feet per minute (others may use higher rates...we're very heavy, and climbing slowly). While holding this reduced rate of climb, we continue to accelerate and retract flaps, incrementally, until we're at an airspeed of V2 plus 100 knots, and we climb at whatever climb rate we can on climb power and V2 plus 100. For us, that's nearly always well above 250 knots. When we're at a weight that allows V2 plus 100 at a speed less than 250, we accelerate to 250 and hold that speed, using pitch to keep the speed in check (climb faster if the airplane wants to go faster). At 10,000', we accelerate to our climb airspeed, generally about V2 plus 170 knots.
The airplane doesn't accelerate through the speed; if you have a speed limit, you control it through pitch and or power.
Remember with respect to engine speed that it may very well not be the limiting factor. Turbojets increase engine speed by adding more fuel to the fire, producing more exhaust gasses to drive the engine faster. As this happens, the engine gets hotter. Temperature limits may very well prevent the engine from accelerating any faster, long before RPM limits are reached. Likewise, internal pressure limits, sometimes identified on some engines as EPR limits (measured as the difference in pressures between the front of the engine, and the back of the engine) may also be limiting factors...the engine RPM is just one parameter to consider...and while it may be the primary power setting instrument in some airplanes, it may not be the one that limits how much power may be used on a given day.
jonathon68
17th Aug 2008, 16:04
Q1.
The calls from what was then called the PNF (pilot not flying), and is now called PM (pilot monitoring) were speed relative to the VREF for the landing flap setting (eg plus 11) and V/S - descent rate in feet per minute (eg 1000 or 750 etc).
The 1000 foot call in the video clip (quite soft in volume) is made by the computerised Rad Altitude callout, to which the PM responds "landing checklist complete".
Don't see too many long sleeves and cuff-links on CX flight decks these days!:D
Selfloading
18th Aug 2008, 07:15
Wow, I didn't ask the question but thank you to SNS3Guppy for providing such a detailed answer :ok: