Hi,
Always love a good tech topic.
1. The sterile cockpit info is correct, but the bongs on take off are really to alert the cabin crew that it is OK to move about the cabin. This is usually achieved with a quick off/on of the no smoking signs. The bong is not always at 10,000 ft, Most airlines let the cabin crew work as soon as it is safe, this could be 3000 ft. It is normal practice to release the passengers once you are over 10,000 ft, again if it is safe, and it is at the captains discretion.
2. Most modern aircraft (747 etc.) are designed to fly with a slight 2-3 degree nose up attitude, for aerodynamic reasons.
3. In the UK/Europe transistion altitude differs from airport to airport and is marked on the approach charts, in the US it is always 18,000ft. The Transition altitude is the height above which aircraft fly with a standard altimeter pressure setting (calibration) of 1013mb, below this height aircraft are given the local altimeter setting in weather reports and by atc.
Hope this helps.
Neil.
PS: Almost forgot, it is not unheared of to see Airbus A340 captains and first officers boarding with large bunches of helium baloons! [:0]
Always love a good tech topic.
1. The sterile cockpit info is correct, but the bongs on take off are really to alert the cabin crew that it is OK to move about the cabin. This is usually achieved with a quick off/on of the no smoking signs. The bong is not always at 10,000 ft, Most airlines let the cabin crew work as soon as it is safe, this could be 3000 ft. It is normal practice to release the passengers once you are over 10,000 ft, again if it is safe, and it is at the captains discretion.
2. Most modern aircraft (747 etc.) are designed to fly with a slight 2-3 degree nose up attitude, for aerodynamic reasons.
3. In the UK/Europe transistion altitude differs from airport to airport and is marked on the approach charts, in the US it is always 18,000ft. The Transition altitude is the height above which aircraft fly with a standard altimeter pressure setting (calibration) of 1013mb, below this height aircraft are given the local altimeter setting in weather reports and by atc.
Hope this helps.
Neil.
PS: Almost forgot, it is not unheared of to see Airbus A340 captains and first officers boarding with large bunches of helium baloons! [:0]
Sailor99 wrote:
"- You will then hear the clunks and bangs of the wheels being retracted - this is done by one of the crew who stays in the hold during take off with a big spanner to wind them up ."
Are you serious? probably not. But CAN they lift them manually in an emergency?
Talking about bumps inflight it is amazing how some FA's and passengers can stomp in the aisle so hard that you can be woken up by the bumps...
TTFN
Paul
"- You will then hear the clunks and bangs of the wheels being retracted - this is done by one of the crew who stays in the hold during take off with a big spanner to wind them up ."
Are you serious? probably not. But CAN they lift them manually in an emergency?
Talking about bumps inflight it is amazing how some FA's and passengers can stomp in the aisle so hard that you can be woken up by the bumps...
TTFN
Paul
Originally posted by Virgin Lover
Hi,
2. Most modern aircraft (747 etc.) are designed to fly with a slight 2-3 degree nose up attitude, for aerodynamic reasons.
Neil.
PS: Almost forgot, it is not unheared of to see Airbus A340 captains and first officers boarding with large bunches of helium baloons! [:0]
It is the most fuel efficient position for the aircraft.
Did I miss something with the ballons [?]
Yes I believe there is a manual back up for the wheels. BTW it is true about the crewmember winding them up. If you arrive at the gate really early you will see the crew playing paper, scissors, stone to see who gets the rotten job. It is also a tradition that once the wheels are up the crewmember climbs through the hatch in the cockpit floor. The Captain then gives him/her a swig of rum from his private stash. The locking mechanism on the wheels is called the brace, so this is where the phrase 'splicing the main brace' comes from. The crew member then has to join in the flight deck fun by doing an impression of Mutley from Whacky Races.
Originally posted by sailor99
Yes I believe there is a manual back up for the wheels. BTW it is true about the crewmember winding them up. If you arrive at the gate really early you will see the crew playing paper, scissors, stone to see who gets the rotten job. It is also a tradition that once the wheels are up the crewmember climbs through the hatch in the cockpit floor. The Captain then gives him/her a swig of rum from his private stash. The locking mechanism on the wheels is called the brace, so this is where the phrase 'splicing the main brace' comes from. The crew member then has to join in the flight deck fun by doing an impression of Mutley from Whacky Races.
Tee-hee-hee..... (wishing I could do a Muttley impression!)[}:)]
Originally posted by sailor99
There is one noise I have never worked out. If is during climb, but only sometimes, and sounds like ball bearings rolling down inside the roof above your head - any ideas anyone?
I, too, have heard this a few times but only on larger aircraft such as 747 or 777. Haven't got the foggiest idea what it is though.
Excellent and informative topic, Sailor.
Originally posted by sailor99
There is one noise I have never worked out. If is during climb, but only sometimes, and sounds like ball bearings rolling down inside the roof above your head - any ideas anyone?
It could be the Cables and pully's that run throught the aircraft from the cockpit that control the rudder and vertical tail wings.
You can see them here going throught the top of the rear bulkhead.
The 747 is not a fly by wire aircraft unlike the 777 but the 747-8 will be.
Few quick answers;
1, The ball bearing noise is ice in the air conditioning distribution ducts.
2, No hydraulic PTU's on the A340. The whine you sometimes hear is the slat or flap actuators. They are basically a hydraulic motor driving a torque tube to the individual slat/flap angle gearboxes. If still on the parking bay it could be the hydraulic pump coming on to operate the cargo door (on the A340, the B747 doors use electric motors)
3, Landing gear back up. As you can imagine getting the gear up is less important than getting it down. To this end there is a back up system to release the landing gear up locks. This releases both the doors & the gear, obvious to look at when it happens as all the gear doors will be open. On the subject of landing gear & locks, the loud clunk to be heard when the gear comes up is the uplock.
4, A346 take off runs. This is based on economics, why take the engine to max power if the aircraft is flying below MTOW & the runway is 3 miles longer. Basically use the maximum required thrust for the take off conditions.
1, The ball bearing noise is ice in the air conditioning distribution ducts.
2, No hydraulic PTU's on the A340. The whine you sometimes hear is the slat or flap actuators. They are basically a hydraulic motor driving a torque tube to the individual slat/flap angle gearboxes. If still on the parking bay it could be the hydraulic pump coming on to operate the cargo door (on the A340, the B747 doors use electric motors)
3, Landing gear back up. As you can imagine getting the gear up is less important than getting it down. To this end there is a back up system to release the landing gear up locks. This releases both the doors & the gear, obvious to look at when it happens as all the gear doors will be open. On the subject of landing gear & locks, the loud clunk to be heard when the gear comes up is the uplock.
4, A346 take off runs. This is based on economics, why take the engine to max power if the aircraft is flying below MTOW & the runway is 3 miles longer. Basically use the maximum required thrust for the take off conditions.
I watched a programme about the building of the A380, and part of it was the design of the wheels and the fail safe which ensured that the wheels got down even if all the engines failed.
As far as I understood they just drop when the system detects that it can't be done in the conventional way. However on the programme the doors prevented the wheels from falling because they didn't open all the way...
As far as I understood they just drop when the system detects that it can't be done in the conventional way. However on the programme the doors prevented the wheels from falling because they didn't open all the way...
Whats the link between the engines failing & the landing gear, hydraulic power is the requirement?? The gear will push the doors out of the way when it free falls, there are grease plates on the 744 doors & rub strips on the A340. On the A340/B747 it's a selection by the crew, doubt the A380 will be any different
Thanks for the info Denzil. Ice in the ducts fits the description perfectly. I have not heard it in some years, but it did sound like ice on the outside of the plane breaking off and running back along the body. I coul dnever understand this as, if I recall correctly, we were in Mexico City at the time (which is not really known for having an icing up problem at its airport!).
The manual system on the airbuses sound pretty common sense. So it is only on the Boeings that the crew member has to remain down below?
The manual system on the airbuses sound pretty common sense. So it is only on the Boeings that the crew member has to remain down below?
Who is online
Users browsing this forum: Google [Bot] and 178 guests