safety question

[eliptic]

Hi All,

Have a question regarding MA60 Aircraft tires.

I was flying with ZestAir (former Asian spirit ) from Boracay-Manila , when boarding i did see that one tire on the main landing gear was totally blank and i did see the cord going out on an area of 6 x 6 cm.

I told the cabin crew and they told me the ground tech staff did clear the aircraft even with the tire like that.
I insisted that the purser anyway did make shore the captain got noticed about this.

On the flight i told the purser that i would like to talk to the Captain if possible or i will make a report when arrive to Manila, when landed i went to the cockpit to talk to the Captain but he didnt wanted to say anything and a few seconds later a airline representetiv come to tell me to let the crew alone and ask what kind of technical experiance i have on aircrafts.

When i was going to show him the cord damage we notice ;-) that the aircraft perfectly parked with the damage covered underneath. haha.

Anyway he promice that regards to manufacture manual it is no problem to fly with a tire where the cord coming out if it is only 1 or 2 layer loss,,,,hmmm

I am a racecar driver since 25 years and alot of mechanical experience and this makes no sence to me....!!? Anyone here can tell me if im wrong???

Thanks for a the great site guys

Lars

Ps. i paste a mail i got from the Airline rep Ds.

<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

Hello Lars,

I'm sorry for the late email, as promised.

I was indisposed for a few days and have been kept very busy over the last 2 weeks.

Allow me to give you a short briefing on "tire mantenance" (reference 890x300 7.50 - 10 Aircraft Tire Service and Maintenance Manual) for the MA60 aircraft.

.......

1 Tire Structure and Name of Every Position....the "first ply cord" means the tread reinforcing ply, the "second ply cord" means tire carcass ply.

B. Check Tire Abrasion Case

(1) 890x300 tubeless aircraft tire
a. The tire shall be changed when the tire crown wears to the degree that the first ply cord can be seen. The changed
tire can be retreaded again.
b. In external field (outlying stations) when the tire crown wears to the degree that the first ply cord can be seen, and there
is no tire for replacing,being changed after flying back to depot is permitted, but it shall not be retreaded.
.......

Given the above technical provisions, there was really no need to worry about the exposed tread that you saw in the main landing gear of the MA60 aircraft that you took.

I hope I meet you again when you take our future flights.

ART M ALEJANDRINO

[arkmark]

I don't think you had any cause for concern. With aircraft tyres, what appears to be significant is often just normal wear.

Aircraft wheels are a pretty amazing piece of engineering, and are a mature technology that cops a pretty high stress life.

Airline staff (usually qualified engineers, PLUS the flight crew) generally inspect wheels and brakes as part of the turnaround or pre-flight inspection. If wear or damage is within limits then it is not required to be changed.

Depending on the particular wheel limits 6 x 6 centimetres is quite small. The cord that you are viewing is usually intended as an indicator layer.

So for your safety question, and its quite appropriate, chances what you were seeing, to the trained eye is just normal wear within limits, indicating that a tyre change will be needed soon -- usually on the overnight, unless of course as you say the obvious wear is not facing the ground, and then the chances are it will be changed on the following overnight !!!!!

[eliptic]

Thanks for the answer Arkmark and cosmos

I guess i maybe overreacted then,, but why they even bother to make tread on the tires if not needed? must be great to land in heavy rain with all "slicks":ooh:

[arkmark]

Also a good question and one I have never been sure of myself.

I think it comes down to ground handling characteristics of an aircraft compared to a car.

An aircraft would displace most water from beneath it's tyres at speed. During this time control authority (effectiveness) transitions between either wheels and breaks and aerodynamic surfaces & engine reverse thrust.

Wheels & brakes are more effective at lower speeds and in pretty much straight lines, so water displacement is less of an issue compared to cars that corner at high speed.

Also, aircraft have a MUCH MUCH MUCH heavier footprint on their wheels than do cars.

It's for these reasons that I am pretty sure aircraft are happier on slicks than other vehicles.

You will be interested to know that aircraft do have different runway length requirements depending on whether it is wet or dry, and whether all thrust reversers are serviceable.

[eliptic]

"Zest Airways MA60 crash landing in Caticlan - Boracay"

"Reports said that strong winds caused the aircraft's landing gear to explode"

WOOWWW.. i didn´t see this post until now,,how the H did they dear to fly with that tire after that accident.

And now i understand why the "Air rep" was so eager to hyssssssss this incident down

http://www.pprune.org/south-asia-far-east/357571-zest-airways-ma60-crash-landing-caticlan-boracay.html