Aquaplaning speed
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Aquaplaning speed
Does anybody out there fly any type of a/c that has a real time read out of the current tyre pressures?
I approached Ronaldsway recently in heavy rain, "runway wet, wet, wet" (the radar man said) - and the phrase "nine times square root of tyre pressure" sprang to mind.
Now if only I had taken a pressure gauge to the tyres on my walk round....
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Hunting is bad!!
Support the right to arm Bears!!
I approached Ronaldsway recently in heavy rain, "runway wet, wet, wet" (the radar man said) - and the phrase "nine times square root of tyre pressure" sprang to mind.
Now if only I had taken a pressure gauge to the tyres on my walk round....
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Hunting is bad!!
Support the right to arm Bears!!
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Cub, you are absolutely correct re. the 9x sqaure root of tyre pressure etc., but I know of no a/c with the readout you mention. I would imagine that if such an animal exists, it would be some brand new all singing all dancing job that most of us have never seen. I know that the Airbus doesn't have it, and I don't think the Boeing does either.
I would imagine that you best policy (as I'm sure has already occurred) is to use the tyre pressure that the book says your tyres should be inflated to - I'm sure they won't be that far off. Personally, I would work it out for whichever set of tyres (mains or nose) has the lowest pressure and use that speed - thereby ensuring you maintain directional control.
I hear the rain in the IOM has been quite something - no change there then!!
Hope this Helps
SLT
[This message has been edited by SLT (edited 04 October 2000).]
I would imagine that you best policy (as I'm sure has already occurred) is to use the tyre pressure that the book says your tyres should be inflated to - I'm sure they won't be that far off. Personally, I would work it out for whichever set of tyres (mains or nose) has the lowest pressure and use that speed - thereby ensuring you maintain directional control.
I hear the rain in the IOM has been quite something - no change there then!!
Hope this Helps
SLT
[This message has been edited by SLT (edited 04 October 2000).]
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The A340 has this option and it shows the tire press. For practical purposes you should have in mind the aquaplaning speed ,and it is calculated as follows;
7.7x squqre root of the main tire pressure. when you depart your tire pressure is correct hopefully because it is part of the checks done by maintenance and the pilot just has to satisfy himself during walkaround that it is o.k otherwise he can have it checked . So for example the aquaplaning speed for the L1011 is 112 knots. I hope this will be an answer to the inquiry , the tire press you can get from your Manual .
7.7x squqre root of the main tire pressure. when you depart your tire pressure is correct hopefully because it is part of the checks done by maintenance and the pilot just has to satisfy himself during walkaround that it is o.k otherwise he can have it checked . So for example the aquaplaning speed for the L1011 is 112 knots. I hope this will be an answer to the inquiry , the tire press you can get from your Manual .
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TPIS - Tire Pressure Indicating System.
It's an option on the 744 and I think standard on the 777 as CX chooses to have the bare minimum on their 400's, (No Auto-start, No taxi light just turn-offs, No PVD, No Headrests, No Full face Oxy, No Therapeutic Oxy, No lower Weather radar they have a torch, No Elec Driven Hyd pumps on 2 & 3, No TPIS, No Doors Auto/Man Indication even though the system is fitted when the A/C is built the wires just aren't hooked up, Plus the bare minimum on the PFD, ND and EICAS).
[This message has been edited by CCA (edited 05 October 2000).]
It's an option on the 744 and I think standard on the 777 as CX chooses to have the bare minimum on their 400's, (No Auto-start, No taxi light just turn-offs, No PVD, No Headrests, No Full face Oxy, No Therapeutic Oxy, No lower Weather radar they have a torch, No Elec Driven Hyd pumps on 2 & 3, No TPIS, No Doors Auto/Man Indication even though the system is fitted when the A/C is built the wires just aren't hooked up, Plus the bare minimum on the PFD, ND and EICAS).
[This message has been edited by CCA (edited 05 October 2000).]
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OK...so how about adding the runway specific gravity to the ATIS?
This could be the start of a job creation scheme - get some person to go out and take three readings every 30 minutes (they won't block the runways for long).
....but it still comes back to knowing what the tyre pressures are - and are they affected by regional QNH?
How about more job creations...as well as waiting on stand for the refueller, you could all wait for the tyre pressure man to come along with his pocket pressure gauge from Halfords and take the readings.
Another little placard to put on the pedestal with the "cabin secure" card - just for tyre pressures.
Wonder how long it would take on a 747 with..what, is it 18 or 20 wheels?
P.S. .... yes, I'm teasing.
------------------
Hunting is bad!!
Support the right to arm Bears!!
This could be the start of a job creation scheme - get some person to go out and take three readings every 30 minutes (they won't block the runways for long).
....but it still comes back to knowing what the tyre pressures are - and are they affected by regional QNH?
How about more job creations...as well as waiting on stand for the refueller, you could all wait for the tyre pressure man to come along with his pocket pressure gauge from Halfords and take the readings.
Another little placard to put on the pedestal with the "cabin secure" card - just for tyre pressures.
Wonder how long it would take on a 747 with..what, is it 18 or 20 wheels?
P.S. .... yes, I'm teasing.
------------------
Hunting is bad!!
Support the right to arm Bears!!
Guest
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tyre pressures are required to be checked as part of the daily. this is in the tech log on our company aircraft and can be referred to. question is , how does the temperature exposure at cold and high altitudes affect tyre pressure on a long flight (cold soak). so without a gauge indication, tpis, the calculations are all out the window. if you are not happy, maybe use a low pass and afterburners to dry out the runway. 
or find a dry place that has a good pub.
or find a dry place that has a good pub.