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PW1100G geared turbofan accessory gearbox airworthiness directive

Posted: Tue Oct 29, 2019 1:55 pm
by SteelChair
Seemingly lost among the hype from the Swiss self imposed grounding, I missed that an airworthiness directive was published that requires replacement of the gearbox.

This appears to be a major hit to PW. They claimed the gearbox was designed for the life of the engine. They said they spent 20 years developing this gearbox and that it was bulletproof. In my opinion, a lot of the problems that the GTF has had to this point have been secondary or tertiary. This seems to me to be a major issue and I'm wondering why there hasn't been any conversation about it or more concern focused upon itm

It appears that this AD affects only the GTF version powering the A320 series.

https://www.flightglobal.com/news/artic ... 0g-461267/

Re: Geared turbofan gearbox airworthiness directive

Posted: Tue Oct 29, 2019 2:03 pm
by ikramerica
I remember over a decade back there were discussions on a.net about GTF and the major stumbling block everyone mentioned was the longevity and reliability of the gearbox.

Re: Geared turbofan gearbox airworthiness directive

Posted: Tue Oct 29, 2019 2:07 pm
by lightsaber
Please read the article. This is the accessory gearbox. Not the gearbox driving the fan. Issues with accessory gearboxes plague many engines.


Pratt & Whitney says in a statement that it is working in coordination with Airbus, the regulatory authorities and airline customers “to incorporate upgrades improving the reliability of the accessory gearbox in the PW1100G-JM fleet.”


Lightsaber

late edit: It is the main gearbox for most engines. It just isn't the big gearbox. It is a case where industry jargon is out of date for the GTF.

Re: Geared turbofan gearbox airworthiness directive

Posted: Tue Oct 29, 2019 2:17 pm
by SteelChair
The article is very confusingly worded in my opinion. The writer of the article says main gearbox, which leads one to believe they are referring to the fan drive gear. The PW rep says "accessory gearbox."

At any rate, I stand corrected. But it is another disappointment in this engine.

Re: Geared turbofan gearbox airworthiness directive

Posted: Tue Oct 29, 2019 2:20 pm
by Elementalism
I believe we call this teething issues. Sucks though.

Re: Geared turbofan gearbox airworthiness directive

Posted: Tue Oct 29, 2019 2:21 pm
by Finn350
Here is a link to the proposed AD:
https://www.regulations.gov/document?D= ... -0614-0001

The problem seems to stem from an integrated drive generator (IDG) oil pump drive gearshaft assembly P/N 5322630-01 within the main gearbox (MGB).

Re: Geared turbofan gearbox airworthiness directive

Posted: Tue Oct 29, 2019 2:40 pm
by Erebus
lightsaber wrote:
Please read the article. This is the accessory gearbox. Not the gearbox driving the fan. Issues with accessory gearboxes plague many engines.


Pratt & Whitney says in a statement that it is working in coordination with Airbus, the regulatory authorities and airline customers “to incorporate upgrades improving the reliability of the accessory gearbox in the PW1100G-JM fleet.”


Lightsaber

late edit: It is the main gearbox for most engines. It just isn't the big gearbox. It is a case where industry jargon is out of date for the GTF.


Could we have a correction in the thread title to clarify this?

Re: Geared turbofan gearbox airworthiness directive

Posted: Tue Oct 29, 2019 2:45 pm
by SteelChair
Erebus wrote:
lightsaber wrote:
Please read the article. This is the accessory gearbox. Not the gearbox driving the fan. Issues with accessory gearboxes plague many engines.


Pratt & Whitney says in a statement that it is working in coordination with Airbus, the regulatory authorities and airline customers “to incorporate upgrades improving the reliability of the accessory gearbox in the PW1100G-JM fleet.”


Lightsaber

late edit: It is the main gearbox for most engines. It just isn't the big gearbox. It is a case where industry jargon is out of date for the GTF.


Could we have a correction in the thread title to clarify this?


Why? Is there not a gearbox problem on the GTF engine?

Re: Geared turbofan gearbox airworthiness directive

Posted: Tue Oct 29, 2019 2:52 pm
by Finn350
SteelChair wrote:
Erebus wrote:
lightsaber wrote:
Please read the article. This is the accessory gearbox. Not the gearbox driving the fan. Issues with accessory gearboxes plague many engines.


Pratt & Whitney says in a statement that it is working in coordination with Airbus, the regulatory authorities and airline customers “to incorporate upgrades improving the reliability of the accessory gearbox in the PW1100G-JM fleet.”


Lightsaber

late edit: It is the main gearbox for most engines. It just isn't the big gearbox. It is a case where industry jargon is out of date for the GTF.


Could we have a correction in the thread title to clarify this?


Why? Is there not a gearbox problem on the GTF engine?


Yes, but "Geared turbofan accessory gearbox airworthiness directive" would be less confusing, as everybody thinks that the problem is with the geared turbofan. Technically "accessory gearbox" is called "main gearbox" which creates further confusion.

Re: Geared turbofan gearbox airworthiness directive

Posted: Tue Oct 29, 2019 3:30 pm
by Erebus
SteelChair wrote:
Erebus wrote:
lightsaber wrote:
Please read the article. This is the accessory gearbox. Not the gearbox driving the fan. Issues with accessory gearboxes plague many engines.


Pratt & Whitney says in a statement that it is working in coordination with Airbus, the regulatory authorities and airline customers “to incorporate upgrades improving the reliability of the accessory gearbox in the PW1100G-JM fleet.”


Lightsaber

late edit: It is the main gearbox for most engines. It just isn't the big gearbox. It is a case where industry jargon is out of date for the GTF.


Could we have a correction in the thread title to clarify this?


Why? Is there not a gearbox problem on the GTF engine?


There are multiple gearboxes here. Would be nice to specify which one exactly.

Re: Geared turbofan gearbox airworthiness directive

Posted: Tue Oct 29, 2019 3:34 pm
by WayexTDI
Elementalism wrote:
I believe we call this teething issues. Sucks though.

Maybe literally if the gear teeth break down...

Re: Geared turbofan auxiliary gearbox airworthiness directive

Posted: Tue Oct 29, 2019 3:59 pm
by N212R
SteelChair wrote:
Seemingly lost among the hype from the Swiss self imposed grounding, I missed that an airworthiness directive was published that requires replacement of the gearbox.

This appears to be a major hit to PW. They claimed the gearbox was designed for the life of the engine. They said they spent 20 years developing this gearbox and that it was bulletproof. In my opinion, a lot of the problems that the GTF has had to this point have been secondary or tertiary. This seems to me to be a major issue and I'm wondering why there hasn't been any conversation about it or more concern focused upon itm

It appears that this AD affects only the GTF version powering the A320 series.

https://www.flightglobal.com/news/artic ... 0g-461267/


There is LOST and then there is intentionally buried....you be the judge.