Inop. anti-skid, per MEL.

[Ignition Override]

We just had this yesterday, and luckily it is rare in our fleet. Some planes end up with all four main tires having flat spots, according to one of our mechanics/engineers. Isn't this a bit expensive? Why is it more economical to keep the system on MEL (even for just two days)? The guy said that he had to change all four mains in New***, on a different ship. I decided later during rollout to not make a normal turn off at a hub's intersecting runway (runway 22) , due to the desire to avoid wearing out more tires.

Our MEL states that during an abort, only about 60 or 70% of maximum braking is allowed. Has anyone out there had any problems with an inoperative anti-skid, especially on wet runways? How about refusing to accept the plane, even with all hydraulic systems normal, autospoilers and reverse thrust normal etc?

It is my intention to one day refuse an airplane if our destination is quite short or wet, depending upon the planned landing weight, and possible crosswinds and/or tailwinds. Beware of equipment which automatically transmits wind direction and velocity. At San Antonio (SAT) not too long ago, the actual winds were from the opposite direction of what was reported.

And how often do you guys/gals walk onto a plane with an anti-skid, or a thrust reverser MEL-anything which can decrease your ability to abort or maintain directional control etc :uhoh:?

[Stan Woolley]

I have refused an a/c with antiskid u/s despite pressure from both engineering and operations. The airport had a relatively short runway and a drop of eighty feet if you overran!

I was totally backed by the fleet manager.

I think it's in the MEL to get you somewhere it can be fixed - not to continue carrying passengers as if there's nothing wrong. Given long runways and no 'aircraft carrier' like runoffs I might be flexible for a few sectors.

Antiskid u/s is not allowable on wet runways here.

[john_tullamarine]

It's unfortunate that many have forgotten the background to the MEL approach to life.

If any component/system relevant to the TC is U/S, then the aircraft necessarily is unairworthy as it no longer complies with the TC - a condition for the issue of the CofA. Fine philosophy but impracticable in the real world ...

The MMEL (from which the MEL is developed for the particular operator/regulator) looks at a range of reasonably expected problems and considers the reason for the U/S system in the first place. By invoking relevant restrictions, the risk levels can be kept within the certification boundaries and there is no reason why the defective ship ought not to be considered OK to fly within the published restrictions.

Company policy will dictate routine MEL application and, in general, if the maintainers can't fix it and there is an MEL permission, one should expect the MEL to be invoked.

However, the MMEL doesn't necessarily consider all relevant matters pertaining to this next flight we are contemplating. A particular MEL permission is just that .. a permission, not a direction.

As always, the folk in the sharp end are the last defence in the Reason Model .... a pity in those environments where the pilots are constrained by background pressures to accept the MEL without question ...

[QNH1013]

Ignition Override,
In the case you describe, yes, refuse the aircraft. Your reasons are well founded and it is your call. I don't know what aircraft you are on but for our operations, anti-skid inop operations are only allowed on DRY runways as per Boeing procedure. And of course considering the factors such as runways length you are going to are also key to deciding if you will take the aircraft there. Plus the other performance penalties. From company experience, anti-skid inop is not to be underestimated. You'll also lose your auto brakes, touch down and locked wheel protection. I would only go short sectors to long, dry runways where I'd use minmum braking and more reverse thrust till a slow speed to ease on the brakes. It's really easy to get a flat spot as you described as we are so used to having all the braking and skid protection in our braking system.

[Ignition Override]

Years ago as an FO for years (10) on this fleet, this MEL condition was the case on at least several ships, but I don't remember how many. These old planes have no autobrakes. Sometimes on final approach with the gear down, we saw an anti-skid light illuminate, and if resetting the switch did no good (or barely pulling out on the gear handle/pulling/resetting the circuit breaker), we switched it back to off and just went pretty easy on the brakes, especially if it was on just one side. It never happened on final to a wet or slippery runway, somehow.

As Captain, I've only seen this MEL a very few times, and while operating to airports with long runways. It has been my good fortune not to discover such an aircraft with this type of "deferred maintenance" on a leg into a fairly short and wet runway, or with a gusty crosswind, so far. Before such a flight, I would call Dispatch, after chatting with the FO about his/her opinion, and tell him that I'm not flying it unless it is repaired and "ground checks" good. I'm wondering about fleet reliability after our upper management decides to outsource much more of our maintenance. With outsourcing, only the Maint. Supervisor has to be FAA-licensed, but not the other mechanics/engineers, who all must be supervised (but then, maybe their families won't normally fly on airline ABC, whereas a given airline's OWN mechanics know that their company normally carries their families...) :rolleyes:. But that is another topic .:ouch:

[Old Smokey]

I'm happy enough to accept an aircraft with the Anti-Skid U/S, in the right circumstances, and, in my other life, dutifully prepare RTOWs for aircraft with Anti-Skid Inop.

One thing worries me, and always has, and that is how much braking is the correct amount? If, in a rejected Takeoff you apply too much braking, you'll blow the tyres / tires (note the trans Atlantic multiculturism). If, on the other hand you take it too easy on the brakes, you stand a very good chance of an overrun.

Between a rock and a hard place. How much is enough?

Regards,

Old Smokey

[LEM]

Yes we are left in no man's land... How can we know the feeling of antiskid inop if we've been using it during our whole life????

THIS is the kind of training they should provide us in the sim.

They don't trust us when it comes to manual flight, but they expect us to show test pilot skills when they need it! :mad:

[411A]

\\\THIS is the kind of training they should provide us in the sim.\\\

Oddly enough, it has been included in a good many L10 checks that I have had, over the years.

I have only had the 'pleasure' of having actually used anti-skid to its maximum effectiveness one dark and stormy night at the old Taipei airport, landing easterly.
The 'ole foot thumpers (yes, they actually did) in older 707's worked to perfection...otherwise it would have been into the weeds for sure.

To dispatch with anti-skid inoperative, one must use all available caution...how do you know for example, that your destination might not be closed, and the alternate wet and short, even if the forecast says otherwise?

Murphys law applies.

[BizJetJock]

On the Challengers anti-skid inop is a no-go item. The manual states that virtually any application of brakes over 80knots will blow the tyres without it. It happens every time in the sim, but luckily I haven't tried it in the aeroplane.
As an aside, I always used to laugh at the preamble to the old CAA MEL's, which described the scenario of an engineer trying to persuade a pilot to delay his flight so that the item could be fixed while the pilot wanted to take the aircraft as it was...!??:D

[ManaAdaSystem]

NG -800 has some 7,5 ton penalty for A-skid inop. No go on wet rwys.
I've spoken to a pilot who landed A-skid inop during an emergency. He tried very hard to brake with caution, but blew the tires. 737 size aircraft.
I haven’t been faced with this dilemma yet, but I'm 99% sure I would not take the aircraft from home base.
I simply do not have the experience and qualifications to do a high speed abort with no anti skid.

[Ignition Override]

Apparently (at many airlines?), the people in Maintenance Control who direct routings of certain ships in order to repair certain MEL items, don't mind the risk of blown tires, maybe frequent replacements. After many years here, still don't know whether Dispatch makes every effort to avoid sending these planes towards airports where anything more than drizzle is forecast, or whether Marketing can influence this, wanting a stretched series where more seats can be filled (despite possible weight penalty).