Well if it had been disarmed and crosschecked how did it deploy? Is there some button on them to push or when the door opened did it pop? Is it different than the mainline jets when disarmed in that it is still possible to pop? I thought disarmed and crosschecked meant the slides were unhooked and disarmed so they wouldnt pop or do the FAs not disarm and crosscheck door 2 on this plane?
RJ Tire Woes.
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Well if it had been disarmed and crosschecked how did it deploy? Is there some button on them to push or when the door opened did it pop? Is it different than the mainline jets when disarmed in that it is still possible to pop? I thought disarmed and crosschecked meant the slides were unhooked and disarmed so they wouldnt pop or do the FAs not disarm and crosscheck door 2 on this plane?
BoeingBoy
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Not all doors are disarmed except at RON's. One of the F/A's can correct me if necessary, but I think on the 737 the 2R door is left armed at stops during the day - 2L is disarmed since catering uses that, as is 1R (catering again) and 1L (entry door).
Jim
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The 757 2R door is armed at all times even when the a/c ron....
ab321 2l 2r 3l 3r are armed at all times even when a/c ron....
the other doors are always un armed if pax are boarding, ac is at gate(only armed if a/c is going to move) unless you are at a hardstand and then usually the aft most door a/c r is armed.
USCREW
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You are correct. Disarmed and cross-checked means that the slides can not deploy. The cleaner armed the door and then opened it. He tried to blame it on the B but the captain backed her up since on the Airbus, there are door indicators in the cockpit. Also, flight attendants rarely open the 2R door for any reason.
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john john,
Keep in mind that what I'm about to say is based strictly on mainline type aircraft, the 727 & 737-200/300/400 specifically, so may or may not apply to the tires on smaller planes.....
I've never seen a tire changed for what would be considered a normal wear pattern on your car - the tread pretty uniformly worn to limits around the circumference of the tire. And it's that type of wear - relatively uniform - that should be caused by using shorter runways with greater break application (plus the normal wear from taxiing).
What generally causes a tire change (other than damage from running over something) is a spot worn to the point of requiring the change, caused by the initial contact with the runway on landing when the tire is not rotating. On contact, the rubber is ground off till the tire/wheel comes up to speed and at some point one of these spots will be worn down enough to cause a tire change. Note that this wear is the same regardless of runway length since it happens at touchdown/spinup.
One factor that would affect RJ's more than bigger aircraft is tire size - specifically diameter. Takeoff/landing speeds are similiar to mainline aircraft, yet the tires have a much smaller diameter. Put those two together and you get much higher tire rotational speeds (RPM) on takeoff/landing than with larger aircraft. Any damage/weakness would be more likely to result in tire failure when the rotational speed (and thus stress) is greater.
Jim
Keep in mind that what I'm about to say is based strictly on mainline type aircraft, the 727 & 737-200/300/400 specifically, so may or may not apply to the tires on smaller planes.....
I've never seen a tire changed for what would be considered a normal wear pattern on your car - the tread pretty uniformly worn to limits around the circumference of the tire. And it's that type of wear - relatively uniform - that should be caused by using shorter runways with greater break application (plus the normal wear from taxiing).
What generally causes a tire change (other than damage from running over something) is a spot worn to the point of requiring the change, caused by the initial contact with the runway on landing when the tire is not rotating. On contact, the rubber is ground off till the tire/wheel comes up to speed and at some point one of these spots will be worn down enough to cause a tire change. Note that this wear is the same regardless of runway length since it happens at touchdown/spinup.
One factor that would affect RJ's more than bigger aircraft is tire size - specifically diameter. Takeoff/landing speeds are similiar to mainline aircraft, yet the tires have a much smaller diameter. Put those two together and you get much higher tire rotational speeds (RPM) on takeoff/landing than with larger aircraft. Any damage/weakness would be more likely to result in tire failure when the rotational speed (and thus stress) is greater.
Jim
