Oracle, bear in mind the 0541153 U bolt is only used in 56-71 172's and 56-61 182's all the other spring leg models have a different design or part number (150/180/182 post 62/185/206). Also most US operators will not comply as they do not have too so perhaps my numbers are not far off considering that if you do CPCP the replacement is not required.
The AD overrides the SID so the 500 hour MPI still stands.
The 1,000 hour replacement is not new, it was introduced by Cessna SE78-68 on the 20th November 1978. Obviously your well maintained Schedule 5 C172 would be compliant? This is the bit that will piss you off, the Bulletin lists the price at US$10.20 each!
So they have not used that part since 1971 and the 1,000 hour replacement was introduced in 1978. The original production line was moved and someone would have had to drag out the drawings and crank up production most likely with a new vendor, your lucky they even support your dinosaur as I am sure in many other industries such low volume parts would not be available. At a guess I would say that the average flight time for an aircraft with that part number U bolt would be less than 50 hours a year if that.
China .......... one word SKYCATCHER, wasnt that a success and so affordable
. Would love to see a 50 year old Great Wall .... you get what you pay for. Try buying Great Wall parts now let alone when the vehicle is 40-50 years old, there is a ute in my local panel shop that has been sitting for 4 months waiting for parts.
Do you really believe the Chinese are interested in punching out low volume hand made light aircraft, the money is high volume goods and rubber dog sh*t.
As for new designs who cares the Cessna line works, aging aircraft will not be an issue with the Cirrus or Diamond as they will be long dead but for sure the mighty Cessna's will live forever with TLC.
As yr right states many that have light aircraft really can not afford them.
If it F*#ks, Flies or Floats ... Rent it don't buy it!