Jump to content

ANTI SKID LIGHTS


herky400M
 Share

Recommended Posts

HELLO C-130 WORLD, WE HAVE A MAJOR DISCUSSION ABOUT THE ANTI SKID WARNING LIGHTS :cool:: DURING LANDING AND USING THE BREAKS WHAT DO THE ANTI SKID WARNING LIGHTS DO?

A) STAY OUT?

B) FLICKERS (BLINKING)

C) COME ON AND STAY ILLUMINATED DURING THE BRAKE MANOEUVER

D) SOMETHING ELSE (PLEASE EXPLAIN)

THX 4 COOP

BOB :)

Link to comment
Share on other sites

Whether or not they illuminate during braking depends on if the pilot is applying enough brake pedal force to cause a tire skid. If not, the lights do not come on. If he does, and this depends on many factors like gross weight, runway conditions, etc., the lights will illuminate when the antiskid control box detects a skid and is cycling the anti-skid control valves to dump brake pressure. They'll go out when that cycle is complete.

Link to comment
Share on other sites

On the ground lights out.

Test Lights illuminate as the anti skid valves cycle and release pressure (simulate a locked wheel/skid) the aircraft should move (if not add a little power and retest) (should feel a bump in the brake pedals) then lights go out.

To taxi test you are trying to "overload" the braking capability and cause a skid. It may be easier to "wet" the tires to reduce their "sticking" ability.

Once the brakes lock the lights should illuminate (brake pressure releases)

Link to comment
Share on other sites

Quoting: (C-13H Training Manual)

“During the landing roll, the test panel lights may flash “on†and “off†momentarily, indicating which wheels are utilizing full anti-skid controlâ€.

Based on the above I am assuming that;

The possibility for the lights to flash during ground operation is only when a wheel/wheels inter a full skid condition that trigger the “Positive Locked Wheel Protection Circuit†= full pressure release signal.

Mean while in the case of approaching skid conditions (detected by “Rate Detection Circuit†in which system will act only to reduce the hydraulic pressure) light should not be expected to come on.

In deferent words:

“Positive Locked Wheel Protection Circuit†triggered = light will come on.

“Rate Detection Circuit†triggered = light will remain off.

Link to comment
Share on other sites

  • 3 weeks later...

I agree with the quotes above, but how can I prove this? written somewhere in any tec-manual or operational manual?

thx !!!

.be

I haven’t read any technical or operational manuals “yet†putting the anti-skid lights during the rolling phase as a functional reference check.

Therefore we shouldn’t expect to have a direct reference in technical or operational manuals of how lights should behave during the actual skid conditions.

So, your question is a system operation inquiry of when the skid lights would be signalled during the actual skid condition.

To me the correct answer will come only through a deep understanding of the electrical circuits of the anti-skid system.

Bearing in mind that during the “Test Log Circuit†we electrically simulating an optimum full skid condition in which valves and lights should behave accordingly. (During the actual skid the signal will defiantly defer in magnitude).

The quoting below is the only reference I found related to your question and it is not written by tenten it is coming from Lockheed authorized training manuals.:)

Quoting: (C-13H Lockheed Training Manual)

“During the landing roll, the test panel lights may flash “on†and “off†momentarily, indicating which wheels are utilizing full anti-skid controlâ€.

Link to comment
Share on other sites

The "Full anti-skid control" is the key.

If the wheel is determined to be in a skid (by the control box) the control valve will port pressure away releasing the brake and providing the light illumination...

If the rate circuit detects a slowing of a wheel (based on rate of speed change) the valve will vary the pressure to the brake.

("inputs from the wheel transducers and provides a fully modulated pressure") not zero pressure as in a skid...

Link to comment
Share on other sites

This is from the GS. If I figure this right the lights will ony be operative after the test switch is acutated (fwd of aft). If they come on any other time the system failure either partial or complete, depending on the number of lights

The anti-skid test and failure system consists of two independent logic circuits. These circuits are the system test logic and system failure logic.

The function of the test logic is to verify the ability of the wheel control printed circuit cards to function dynamically. The system test logic provides a dynamic test for skid control circuits and an in flight test for the locked-wheel circuits. The system test may be performed only with the parking brake released. A 400 Hz simulated wheel-speed signal is applied to the forward or aft control section by the test switch. When the test switch is released the test

signal is removed from the control section. The removal of the test signal appears to the control section as a skid which results in a valve signal to operate the test indicators. Failure logic provides a full time check for failures that would cause the system to be totally or partially inoperative.

Link to comment
Share on other sites

From Personal Flight Test Experience - The individual light WILL flash when that wheel senses a skid during ground operations.

This is a check for check flights from the 6CF-1 (your note or numbers are probably contained there, sorry I dont have a copy anymore) and I could be wrong but there are more than two circuit cards in the Anti-Skid control box, one card per wheel, the two you mentioned and I think there may be one or two more but not sure at this time.

The hardest thing during a check flight was getting a pilot to actually mash down hard enough on the brakes to actually cycle them, also if you are light on dry runway it may even be almost impossible to get the anti skid to cycle, the heavier you are the more chance you have of cycling the system.

I have all the Lockheed manuals in PDF on my laptop over in the house, when I go there in a bit I will open em up and look.

Let us know what you find, interesting problem.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...