Practical Hydroplanning Advice

[Iceman49]

Landed on a runway after a rainfall, this particular base rarely experienced rain. As soon as the reversers were deployed we were traveling sideways down the runway. There was nothing in our training to account for this unusual manuver...when in doubt reverse what you had previously done. Reversers were stowed, aircraft recentered...don't remember what I did with the brakes. Tower asked if we were ok...said I needed a clean flight suit.

[bayete]

Maybe you should ask these guys about hydroplaning.
YouTube - The Runway is Wet

[Intruder]

Landed on a runway after a rainfall, this particular base rarely experienced rain. As soon as the reversers were deployed we were traveling sideways down the runway. There was nothing in our training to account for this unusual manuver...

Our Flight Handbook addresses the issue in the "Wet/Slippery Runway Landings" section. Initial training includes discussion and pictures with appropriate vector diagrams.

The reverse thrust side force and a crosswind can cause the aircraft to drift to the downwind side of the runway if the aircraft is allowed to weathervane into the wind. As the aircraft starts to weathervane into the wind, the reverse thrust side force component adds to the crosswind component and drifts the aircraft to the downwind side of the runway. Main gear tire cornering forces available to counteract this drift will be reduced when the anti-skid system is operating at the maximum braking effectiveness for existing conditions.

To correct back to the centerline, reduce reverse thrust to reverse idle and release the brakes. This will minimize the reverse thrust side force component without the requirement to go through a full reverser actuating cycle, and provide the total tire cornering forces for realignment with the runway centerline. Use rudder, steering and differential braking as required to prevent overcorrecting past the runway centerline. When re-established on the runway centerline, reapply steady brakes and reverse thrust as required to stop the aircraft.

[Iceman49]

Military 1975

[jcbmack]

Keep those tires properly inflated!!!

And no, the FAA does not specify much on reverse thrust.

[OverRun]

The website is not co-operating for the link to:
PHENOMENA OF PNEUMATIC TIRE HYDROPLANING (1963) By Walter B. Horne and Robert C. Dreher

I shall keep trying, but a slightly later paper by Tom Yager of NASA on FACTORS INFLUENCING AIRCRAFT GROUND HANDLING PERFORMANCE is here. It's a good read.

[Checkboard]

It's a PDF file-here is the actual address:

http://ntrs.nasa.gov/archive/nasa/ca...1964000612.pdf

[Microburst2002]

Yes indeed
If there is a change in the next revision it means they have spies watching PPRUNE
And Boeing pilots will owe it to you!

Cheers

[Pugilistic Animus]

What is the maximum allowable tire pressure differential allowed for part 119 operators?...can you yourself just check with a gauge?

[Ocampo]

Reading this topic something immediately came up to my mind.
One landing from a 4 hour flight on a Piper Cherokee, heavy rain shower just 15 before landing, even the low-level CB's were still there when we were on finals. Tried to plant it (turned out to be no so "planted"), and right away, after nose gear touchdown the tail starts to swerve(?) erratically left to right (like the racing motorcycle's tail when the bloke is about to be thrown to the floor). Immediate reaction, elevator nose down, don't touch the brakes and let the airplane decelerate by friction. The "scare" came up just after the turn-off.
I guess it happens to the little ones as the big ones also...who would've thought?

[jcbmack]

FAR 25:

What is the maximum allowable tire pressure differential allowed for part 119 operators?...can you yourself just check with a gauge

Tire pressure should be checked atleast 2 hours after the last operation with a gauge at ambient temperature. A temperature-sensing valve in each tire can release air pressure on aircraft as well.

I found relevant info on tire pressure differentials in FAR 21, 23, and 25.

I look forward to hearing a more thorough response from anyone who knows.

p.s. even with Nitrogen filled tires there will be temp dependent pressure changes that can be modified by a sensing system.

[Pugilistic Animus]

by the pilot??? and for differential answer= 60/40

[jcbmack]

FAR 121:

FAR 121 too. Those who are certified to check the tire pressure.

[Pugilistic Animus]

Does not checking the pressure release the nitrogen and lower the pressure?

all part 119 carriers

[jcbmack]

Ah...okay

Does not checking the pressure release the nitrogen and lower the pressure?

Yes indeed; I should have not missed that.

All 119 carriers; all who are certified.

Thank you PA.

[Pugilistic Animus]

maintenance personnel/ mechanics/ engineers

[jcbmack]

Yeah

...and for differential answer= 60/40

Recent SAFO... yeah pressure would go down from checking the pressure.

[Pugilistic Animus]

for a plotted true course of 090 I find that before correcting for the wind I have to fly a magnetic course of 087 finally with a WCA of 8E giving me a CH of 079 what is my VFR cruising altitude
a. above 3000' agl
b. above FL 180
c. below 1500' agl

[jcbmack]

for a plotted true course of 090 I find that before correcting for the wind I have to fly a magnetic course of 087 finally with a WCA of 8E giving me a CH of 079 what is my VFR cruising altitude
a. above 3000' agl
b. above FL 180
c. below 1500' agl

I choose a more than 3000' agl due to the magnetic course; prior to correcting for wind, the altitude above ground must be atleast 3000' VFR cruising.
MC= true course plus or minus variation. MC between 0 and 179 degrees at odd altitudes MSL plus 500 feet. MC determines odd or even altitudes.IFR traffic could be 500 feet above or below. Staying straight and level is imperative; do not go wandering into other's airspace.
See and avoid, or see and be seen... at higher altitudes aircraft fly faster, thus proper VFR cruising agl is critical. Of course there exceptions for level flight, but these are NOT covered under VFR cruising altitude.
These are: 1000', 1500', 2000', and 2500'. There will be increased traffic below 3000'.

[jcbmack]

FAA

For a synopsis see: Federal Aviation Regulation Sec. 91.159 - VFR cruising altitude or flight level.