Mr Spaceman From Canada, joined Mar 2001, 2787 posts, RR: 8 Posted (13 years 4 months 3 weeks 2 days 5 hours ago) and read 4407 times:
On June 26, 1978 an Air Canada DC-9 (CF-TLV) began it's takeoff roll down runway 23L at Toronto International Airport. It's destination was Winnipeg with 102 passengers and 5 crew members on board.
During the takeoff roll, while approaching 140 knots (Vr was 154 knts) an "Unsafe Landing Gear" light illuminated. The Captain decided to abort the takeoff, however, he didn't have enough runway left to stop (braking performance on the 9,500 foot runway was reduced by dampness and excessive rubber on the runway's surface).
The DC-9 continued rolling almost 1000 ft passed the end of the runway and plunged into a 60-foot-deep ravine where it clipped tree tops and broke into 3 pieces upon final impact. Every person on board was injured and 3 were killed.
After months of investigation, it was determined that a tire had lost it's tread. Pieces of rubber damaged the landing gear position switch on the strut (causing the cockpit alarm), and a large chunk of rubber flew into one engine causing it's failure.
The tire only lost it's tread...it didn't burst. At the time, Transport Canada's rules permitted the use of re-treaded tires on passenger aircraft. Airliner tires were allowed to be recapped a maximum of 6 times. The DC-9's tire had already been recapped 5 times.
My question is:
Does your country permit passenger aircraft to use recapped tires? If so, how many times can they be recapped?
It will be interesting to learn what the different rules around the world are regarding the use of recapped tires. Hopefully we'll hear about the current rules on this topic from some countries in North & South America, Europe, Asia, Australia, Africa, etc, etc.
I guess the most widely known accident involving a tire would be the loss of the Concorde outside of Paris.
Bio15 From Colombia, joined Mar 2001, 1089 posts, RR: 6
Reply 1, posted (13 years 4 months 3 weeks 2 days 2 hours ago) and read 4367 times:
As far as I know, all airlines use retreaded tires. Retreading is not a simple procedure, it ensures good quality tires. Maybe on some locations there are restrictions, but never heard of them.
I recall this accident was discussed previously. The aircraft was already above V1. He couldn't have been below V1 and not have enough runway left for stopping, so not sure if blown tires are to blame. I've seen a 737 land without one gear truck lowered, so I believe the DC9 overrun could have been avoided or replaced by a less endagering situation. Just my opinion though
Dhltech From United States of America, joined Sep 1999, 15 posts, RR: 0
Reply 2, posted (13 years 4 months 3 weeks 2 days 2 hours ago) and read 4337 times:
the tires we use are retreaded and on the side wall it is stamped how many times it has been retreaded i forget what our limit is on the number of times i would have to look but i think it is 20 but that may be to high. the only plane that i have seen with all new tires was a 747 sp owned by a saudi prince.
Bio15 From Colombia, joined Mar 2001, 1089 posts, RR: 6
Reply 4, posted (13 years 4 months 3 weeks 1 day 22 hours ago) and read 4295 times:
A Piedmont Airlines B737-400 diverted from Charlotte to Greensboro due to a problem on the landing gear on August 2 1989. No injuries
I believe the cause was a chock that wasn't removed from the landing gear.
I saw a program on this incident on Discovery. None of the main bogeys lowered, so the pilot did a series of dives and rapid pulls on the yoke to see if gravity could make the langing gear drop. Only one lowered, so he then attempted hitting the runway hard with the available gear to drop the other one, still nothing happened. They landed that way, and the video is quite impressive!
B747skipper From , joined Dec 1969, posts, RR:
Reply 5, posted (13 years 4 months 3 weeks 1 day 19 hours ago) and read 4295 times:
Many maintenance people and "old timers" told me that re-treaded tires are sometimes safer than "new" tires... There is no "set limit" number of times it can be done here in Argentina (they remanufacture them in Brazil for us) but it is function of the condition of the plies... inspections on these tires are very serious matter because so critical for flight safety, especially on takeoff. Re-treaded tires are not "much" less expensive than new tires, they cost about 60 to 75% of new ones, and you must "give a tire" to be re-treaded to get one back...
Some 2 years ago, a "brand new" tire blew up one of of our planes, while on takeoff, apparently had been "unproperly inflated" when installed and got overheated during a long taxi...
And about the Air Canada accident, well, once again when "close" to V1, do not think about aborting a takeoff... Aborting succesfully "at V1" is a thing for "test pilots"... for me, I consider I am committed for takeoff some 10 knots prior to V1... especially if the runway is not perfect and dry... NO airline nowadays recommends to attempt to abort a takeoff NEAR V1...
For those who can have access to the video training tape from Boeing, "V1, go or no-go decision", you will realize that V1 is often... "too late"...
Mr Spaceman From Canada, joined Mar 2001, 2787 posts, RR: 8
Reply 6, posted (13 years 4 months 3 weeks 1 day 10 hours ago) and read 4246 times:
Thanks for your replies. I'm still hoping to learn what the actual rules are concerning re-treaded tires on passenger aircraft for the USA (for an example). What do the FARs state, regarding how many times a tire can be recapped? Dhltech thinks it's near 20 times in the USA, but he's not sure. B747skipper says that there's no "set limit" for recapped tires in Argentina. I guess airliner tire technology has greatly improved since the Air Canada DC-9 accident back in 1978.
>Bio15, Thanks for your reply. Rest assured that the info I posted was from the results of investigations by Transport Canada, Air Canada and McDonnell Douglas. A shreaded tire was the cause of the "chain of events" that led to the aborted takeoff and unfortunate crash.
The Captain of the DC-9 was Reginald Stewart. A Coroner's investigation concluded that Reginal Stewart "could not be faulted".
Capt Stewart explained that he felt a vibration during the begining of his takeoff roll around 50 knts and thought it was just his nose gear tires running over the raised runway centerline lights. He also stated that the vibration increased rapidly and as he approached 140 knots, the undercarriage warning light came on.
Capt Stewart quoted "I felt the tire failed and had done some damage, but I had no idea of the exact damage," he said "The only decision was to reject the take-off".
Amoung several recomendations by the jurors in the Coroner's inquest was that the performance charts for the DC-9's braking performance be ammended because the figures listed were only based on a "bone dry" runway in California.
As B747skipper stated...when close to V1 don't even think about aborting a takeoff. I suspect a crash like this DC-9's might have helped to forge those recomendations.
"Number of Retreads.
The wide variation in tire
operating environments which may affect total carcass
life and serviceability make it inadvisable to
arbitrarily prescribe the maximum number of times a
tire should be retreaded. Tire studies have disclosed
that due to the complexity of aircraft tires, the
separation propagation mechanism is critically
influenced by the overall structural strength and
structural uniformity of the carcass. Small
separations in a weak carcass may propagate very fast
while the same separation in a very strong carcass
will propagate very slowly and go through many R
levels before it will lead to a terminal failure.
Accordingly, the number of times a tire can be
retreaded can only be controlled by a thorough
inspection of the carcass, using the appropriate NDI
methods for each area of the carcass being inspected."
At Delta there is a set number of times a tire can be retreaded. I don't remember what it is but I think it's 10 or 20. Every tire has a serial number on it and records are kept so each tire has a history attached to it.
As a side note aircraft tires that are no longer able to be retreaded for flight use get retreaded for use as jetway tires.
Jetguy From , joined Dec 1969, posts, RR:
Reply 8, posted (13 years 4 months 3 weeks 18 hours ago) and read 4223 times:
Aircraft tires are designed for high impacts and short bursts of high speed. They are not designed for sustained high speeds like an automotive tires. One of my friends was a lead mechanic on a Gulfstream II. As they changed tires they would put the old ones in the corner of their hangar and periodically take them to the dump for disposal. One day he got the bright idea to see if they would fit on the rims of an old camp trailer that he had - it needed new tires pretty badly. They fit and he mounted a set, loaded up the trailer and drove off with them. He only got about 30 miles out of town when the first one blew. He mounted the spare and drove another 5 or 10 miles when the other one failed. Evidently, the sidewalls on aircraft tires don't have a lot of flex and they build up heat very rapidly. It didn't take very long for the tires to fail.
L-188 From United States of America, joined Jul 1999, 30262 posts, RR: 57
Reply 9, posted (13 years 4 months 3 weeks 17 hours ago) and read 4222 times:
We used to use Swamp buggies for hunting. There where homemade rigs usually using a Chevy straight six engine, some body parts off a GMC 6*6, combinded with a homemade box/bed, a frame homemade from drill pipe and surplus duce and a half axles bolted directly to the fram without benfit of springs.
For wheels they used to use DC-3 or DC-6 mainwheels. On some of the more modern ones they switched over to C-130 mainwheels. My uncle one time ended up with a lot of C-130 tires that where surplused. All of them had faults that would ground them from military service,or had reached their retread limits, but on a vehicle with a 5 mph top end, well they did just fine, and didn't tear up the ground like four wheeler tires do now.
On of the lighter swamp buggys we had (It used a Model A Ford engine) was actually able to float with the aircraft tires it used.
OBAMA-WORST PRESIDENT EVER....Even SKOORB would be better.
Cx flyboy From Hong Kong, joined Dec 1999, 6784 posts, RR: 55
Reply 10, posted (13 years 4 months 3 weeks 9 hours ago) and read 4217 times:
I can't remember how many retreads we can have, but we don't use retreads on our nosegear tyres. This is after we lost a convair880 many years ago when one of the nosegear tyres burst at Kai Tak, sending the aircraft straight off the runway into the harbour, killing a couple of people.