Chocking A/C
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Chocking A/C
hello,
Is there any risk of damage to a/c landing gear, wheels, by chocking the wheels too soon after landing ,in particular Boeing a/c ?
Is there any risk of damage to a/c landing gear, wheels, by chocking the wheels too soon after landing ,in particular Boeing a/c ?
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A/c are parked with the brakes on [unless hot!]
In the 42 some years that I have flown I only set the parking brake until chocks are inserted under the gear. Then the brakes are released.
Smart engineers leave the chocks about 2 inches [50mm] from the tyres so they don't get jammed!
Once on a 727 we had to have the main tires changed because an old tubular metal chock was used and the chock failed cutting into the tires.
Now, to answer the question posed by this thread. No.
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con-pilot
Sorry, but most strongly disagree, respectfully.
In the 42 some years that I have flown I only set the parking brake until chocks are inserted under the gear. Then the brakes are released.
In the 42 some years that I have flown I only set the parking brake until chocks are inserted under the gear. Then the brakes are released.
"Is there any risk of damage to a/c landing gear, wheels, by chocking the wheels too soon after landing?"
Ah, yes, if you chock the gear before you get to the ramp, that's not good.
Ah, yes, if you chock the gear before you get to the ramp, that's not good.
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Well, as I flew 727s for over ten years and have over 7,000 hours as Captain in the aircraft, just what did you do when the 727s were parked over night and the parking brake pressure bled down?
We never, repeat never, left the parking brake on after being chocked. If for no other reason than brake disk warping.
Do you leave the amp selector switch in the Bat Volt position overnight as well?
You show me a 727 parked on a sloping ramp with only the parking brake on and no chocks left overnight and I'll show you a 727 at the bottom of the sloping ramp.
We never, repeat never, left the parking brake on after being chocked. If for no other reason than brake disk warping.
Do you leave the amp selector switch in the Bat Volt position overnight as well?
You show me a 727 parked on a sloping ramp with only the parking brake on and no chocks left overnight and I'll show you a 727 at the bottom of the sloping ramp.
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I've never left parking brakes set. Chock, then release.
Setting chocks back helps keep them from getting trapped. Setting them at an angle to the outboard side of the tire helps break them lose if they do get trapped.
Setting chocks back helps keep them from getting trapped. Setting them at an angle to the outboard side of the tire helps break them lose if they do get trapped.
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Parking brake left set.
In the fifty and some years that I have been involved in aviation, as a ground engineer, flight engineer and pilot I cannot ever recall a normal requirement to leave the brakes applied after having the chocks in place. That applies to all the aircraft I have been associated with from light aircraft to B747's. I am not questioning the posts of those such as mudackace or Feather #3, just a little surprised that their company uses such practice.
Interesting variations on procedure.
The company I fly for leaves the park brake set after shutdown and during turn arounds and the only time I've ever seen otherwise would be for an instance of hot brakes.
Regards,
BH.
The company I fly for leaves the park brake set after shutdown and during turn arounds and the only time I've ever seen otherwise would be for an instance of hot brakes.
Regards,
BH.
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During 42 years I always released brakes after chock insertion, including during 7000 hours on B727. Even on A320 with brake fans, followed same procedure.
There is a story of a RAAF C130A parked on a slope at Kainantu, PNG about 45 years ago. During unloading of a vehicle, army troops borrowed 2 downhill chocks to pevent vehicle runaway. Aircraft rolled but captain was fast enough to chase aircraft, jumped aboard and applied brakes, saving a write-off.
So on a slope, depending on brake temp and company policy, belt and braces would seem appropriate.
There is a story of a RAAF C130A parked on a slope at Kainantu, PNG about 45 years ago. During unloading of a vehicle, army troops borrowed 2 downhill chocks to pevent vehicle runaway. Aircraft rolled but captain was fast enough to chase aircraft, jumped aboard and applied brakes, saving a write-off.
So on a slope, depending on brake temp and company policy, belt and braces would seem appropriate.
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This is really weird. 
In my 45 years in the Industry, Engineer NOT Pilot, and at several different Airlines, we have always chocked aircraft on arrival (yes after stopping) then release the brakes.
IF it is just a turnround then that is it normally, however IF it is on an extended turnround and definitely if overnight, once the brakes are cooled off brakes are parked and chocks left in.
That includes ALL the aircraft I have ever been involved with, including B727s.
In my 45 years in the Industry, Engineer NOT Pilot, and at several different Airlines, we have always chocked aircraft on arrival (yes after stopping) then release the brakes.
IF it is just a turnround then that is it normally, however IF it is on an extended turnround and definitely if overnight, once the brakes are cooled off brakes are parked and chocks left in.
That includes ALL the aircraft I have ever been involved with, including B727s.
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con pilot, Once the parking brake is set, the pressurised hydraulic fluid is trapped in the system. It matters not a jot if the main system hyd pressure drops to zero overnight, the brakes remain ON. 38 years of Boeing ops in EU and we always set the brakes and left them set unless hot.
And if the ammeter flattens the battery overnight, you have a poor battery.
And if the ammeter flattens the battery overnight, you have a poor battery.
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Chocks on..
I do agree with the above said:
Chocks on - Brakes Off
At my last employer we the procedure only to leave the breaks on during very windy conditions (eg +35 kts..), but this is off course a company procedure and might be related to the aircraft type (crj)
now, here in the world of business aviation: NEVER leave the park-brake on, when you leave your aircraft, ´cause it is quite common that your aircraft is moved to a different parking apron after you left...
we even carry our own set of chocks on the plane because you never know where you end up in the end of the day.
my 2 cents
welle
Chocks on - Brakes Off
At my last employer we the procedure only to leave the breaks on during very windy conditions (eg +35 kts..), but this is off course a company procedure and might be related to the aircraft type (crj)
now, here in the world of business aviation: NEVER leave the park-brake on, when you leave your aircraft, ´cause it is quite common that your aircraft is moved to a different parking apron after you left...
we even carry our own set of chocks on the plane because you never know where you end up in the end of the day.
my 2 cents
welle
The other reason to keep the chocks back an inch or two from the tyres where possible is that the a/c is usually much heavier when departing than arriving - the tyres before departure bulge out trapping the chocks in place.
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Leaving the parking brake set slows the cooling of the heat sink, which in turn transfers more heat to the hydraulic fluid, which in turn cases it to become acidic, which in turn causes filter elements and seal to break down more rapidly, which in turn........
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After 30 years flying Boeings... not much has changed except for carbon brakes.
After landing and parked, brakes set... chocks in place... brakes released.
Before engine start, brakes set, tug connected.
If the bird was overnighting... brakes set before shutting it down for the night. I rarely saw brake pressure equal to accumulator pressure. Its a good system with check valves to prevent back flow of fluid or pressure to the normal hydraulic system.
Rejected takeoff??? simple... after the jet comes to a stop... tiller full offset... brakes released to prevent wheel lockup... start the APU and shut down the motors. Whiel the aircraft is being towed to the stand... think about the acivities for the evening... once on stand... chocks in place before tug is disconnected so the brakes don't have to be set.
Go th the hotel, and have a great night.
After landing and parked, brakes set... chocks in place... brakes released.
Before engine start, brakes set, tug connected.
If the bird was overnighting... brakes set before shutting it down for the night. I rarely saw brake pressure equal to accumulator pressure. Its a good system with check valves to prevent back flow of fluid or pressure to the normal hydraulic system.
Rejected takeoff??? simple... after the jet comes to a stop... tiller full offset... brakes released to prevent wheel lockup... start the APU and shut down the motors. Whiel the aircraft is being towed to the stand... think about the acivities for the evening... once on stand... chocks in place before tug is disconnected so the brakes don't have to be set.
Go th the hotel, and have a great night.
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Accumulator pressure will actually drop over time weakening the parking brake force. Unless the hyd demand pumps are on. There was once when a bunch of guys from my place who were towing an a/c to a remote stand couldn't find any chocks and decided to set the parking brake only and then go for lunch. Coming back after lunch, the airport authorities surrounded the a/c as the a/c actually rolled back blocking an active taxiway. Thank God there were no damages.
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Old Fella
Parking brake left set.
In the fifty and some years that I have been involved in aviation, as a ground engineer, flight engineer and pilot I cannot ever recall a normal requirement to leave the brakes applied after having the chocks in place. That applies to all the aircraft I have been associated with from light aircraft to B747's. I am not questioning the posts of those such as mudackace or Feather #3, just a little surprised that their company uses such practice.
In the fifty and some years that I have been involved in aviation, as a ground engineer, flight engineer and pilot I cannot ever recall a normal requirement to leave the brakes applied after having the chocks in place. That applies to all the aircraft I have been associated with from light aircraft to B747's. I am not questioning the posts of those such as mudackace or Feather #3, just a little surprised that their company uses such practice.
On another note it has been common practice in the past on all aircraft I have ever worked with to leave the brakes set during a layover (after they have cooled down). We do not practice this on other fleet types at my current employer.