United 777 drops wheel during takeoff KSFO
So would I! (Must consider replacing my Astra - Aviva, it's said in jest!)
Last edited by jethro15; 8th Mar 2024 at 22:30.
United 777 loses a wheel on takeoff.
Plane carrying 235 forced into emergency landing after wheel falls off during takeoff
A United Airlines jetliner bound for Japan made a safe landing in Los Angeles after losing a tire while taking off from San Francisco.See less
Ah - there are the bearings - 3:55. Then I agree on the flambé seizure of the bearing melting the axle. I think it was a Dash 8?? that had that failure with a spinning wheel of fireworks before the wheel departed following takeoff. Yeah, if the axle isn't turning, but the hubcap is, then clearance won't matter - the bolts will machine exit grooves.
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Just for info: Jacking a wide body airliner for wheel change, if the tyre is flat a crocodile style jack is needed to get under the bogie (truck). The video shows the centre wheel change which is why 2x jacks are required (jacking point near each end of truck) on other non six wheelers only one jack normally required; on wide-body mains almost impossible to jack using a handle, even 2 mtr long and two mechanics, instead these jacks have an air driven motor and yes MechEng correct info, best plan is the adapter hose from the old tyre to the jack, otherwise LP air bottles; these tyres would be in the 200psi+ range and filled with nitrogen
Of the B737, B727, B767, and B777 the B727-200 main wheel tyre is the biggest I have come across and was inflated to about 190psi. Normally after workshop assembly the tyre is fully inflated, placed in a steel cage for a 24hr leak test, the rubber expands a little and cooling causes some pressure loss, then for storage it is deflated to about 50%.
Bosi72, steel, multiplate brakes, have a lot of clearances for expansion etc, and can be segmented like a jig saw puzzle, as the rotors flop around with wheel rotation, they do contact the stators, hence noise, I know next to nothing about Cessna wheels; carbon brakes are a lot quieter.
On my last B747-400 spec circa 2004, the tire pressure monitor was an option, it has plus and minus points in my mind, as no flight engineer to kick the tyre on walk about
and the large difference in pressure between cold and hot destinations can cause quite a lot of confusion for the crew (same with my Mini Cooper S giving me distracting warnings and requiring the car to be driven to get a reading ugh!). Example I inflate wide-body main tyre to 190psi in Arabian Gulf, aircraft arrives in Manchester UK, overnight check finds tyre at 170psi, inflated, plane arrives back in Arabia tyre pressure 205psi and so it goes on and on.
Just found this:
Of the B737, B727, B767, and B777 the B727-200 main wheel tyre is the biggest I have come across and was inflated to about 190psi. Normally after workshop assembly the tyre is fully inflated, placed in a steel cage for a 24hr leak test, the rubber expands a little and cooling causes some pressure loss, then for storage it is deflated to about 50%.
Bosi72, steel, multiplate brakes, have a lot of clearances for expansion etc, and can be segmented like a jig saw puzzle, as the rotors flop around with wheel rotation, they do contact the stators, hence noise, I know next to nothing about Cessna wheels; carbon brakes are a lot quieter.
On my last B747-400 spec circa 2004, the tire pressure monitor was an option, it has plus and minus points in my mind, as no flight engineer to kick the tyre on walk about
and the large difference in pressure between cold and hot destinations can cause quite a lot of confusion for the crew (same with my Mini Cooper S giving me distracting warnings and requiring the car to be driven to get a reading ugh!). Example I inflate wide-body main tyre to 190psi in Arabian Gulf, aircraft arrives in Manchester UK, overnight check finds tyre at 170psi, inflated, plane arrives back in Arabia tyre pressure 205psi and so it goes on and on.Just found this:
Is that the Ferrari in the foreground?
Aeromech3, that's why tyre pressures are stated with regard to temperature. The AMM has a graph to show the nominal pressure at different temperatures.
Good luck with that, how long did it take for United to replace a guitar…2nd time I get to use that line
Just taking a guess here, but, if the wheel or brake (or both) were changed and upon reinstallation of the wheel, the wheel nut lock bolts were NOT installed. What's to stop the wheel nut backing off and said wheel deciding to deplane?
Rgds McHale.
Rgds McHale.
aeromech3,
With respect, wheel rotation has nothing to do with tightening or loosening of said axle nut. The nut is torqued up against a keyed washer/spacer which in turn rests up against the outer wheel bearing face. This in turn holds the bevelled shape of the outer bearing against the matching bevelled shape of the outer bearing seat on the outer wheel hub (same for inner bearing and bearing seat assembly on the inner wheel hub), and it is this matching bevelled shape of the bearings and bearing seats that pretty much holds the wheel on the axle.
The wheel nut and washer/spacer are there to keep the whole assembly together and prevent lateral movement of the wheel and bearings on the axle. So, if the wheel nut was installed WITHOUT the wheel nut lock bolts , there is nothing to prevent the wheel nut eventually backing off and the wheel departing.
Rgds McHale.
With respect, wheel rotation has nothing to do with tightening or loosening of said axle nut. The nut is torqued up against a keyed washer/spacer which in turn rests up against the outer wheel bearing face. This in turn holds the bevelled shape of the outer bearing against the matching bevelled shape of the outer bearing seat on the outer wheel hub (same for inner bearing and bearing seat assembly on the inner wheel hub), and it is this matching bevelled shape of the bearings and bearing seats that pretty much holds the wheel on the axle.
The wheel nut and washer/spacer are there to keep the whole assembly together and prevent lateral movement of the wheel and bearings on the axle. So, if the wheel nut was installed WITHOUT the wheel nut lock bolts , there is nothing to prevent the wheel nut eventually backing off and the wheel departing.
Rgds McHale.