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CanadianNorth
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732: JT8D-9A To JT8D-15 Or -17

Tue Oct 03, 2006 11:41 am

Hi all

Recently I was lucky enough to have a mechanic from Air North give me a little tour of their whole maintenance setup. Very nice of them, and I enjoyed every minute of it. What really made it a special visit was touring around their big tent while they were in the process of doing a C check on one of their 737s.

Air North currently operates 2 737-200s, and both are equipted with the JT8D-9As. I had a good look at these and then when asked about having the better engines on the 732 I was told that with the current cargo demand Air North is finding themselves rather limited with the -9s and rather than replace the engines it would be alot better to just get another 732 with -15s and -17s.

Also, Air North is currently looking for a Combi with -15s or 17s, so they have the option of using it as a 737 freighter, a 737 combi, or just a regular 737 with a little extra power, but thats a whole nother topic there.

Anyhow now that I've done 3 paragraphs worth of rambling I'll get to my question... Just how difficult and expensive would it be to take a 732 with JT8D-9s and convert it to a JT8D-15 or JT8D-17 powered 732?


thanks much
CanadianNorth
HS-748, like a 747 but better!
 
SkydrolBoy
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RE: 732: JT8D-9A To JT8D-15 Or -17

Tue Oct 03, 2006 3:25 pm

It would be very easy to switch over to -15 or -17 engines from a maintenance standpoint, all you would need is a couple engines and some new EGT gauges for the cockpit. The hard part would be on the flight ops side as they would have to modify their manuals and paperwork to reflect the higher power engines. I've swapped several 727's ans 737's from one engine model to the other and the only concern is that you have the right gauges installed in the cockpit. Now to add to this the costs they maybe talking about would be finding some -15/17's with the same Hushkit that is currently installed on the -9's. Some JT8's have the RIGV (respaced inlet guide vanes) hushkit installed which is quite an undertaking to swap over to a new engine if it is not already installed.
 
greasespot
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RE: 732: JT8D-9A To JT8D-15 Or -17

Tue Oct 03, 2006 6:32 pm

EGT gauges need to be changed as well as one saddle duct. Plus the actual airframe has to have the capability to have the -15/17 engines installed.

Just because it is a -200 airframe does not mean it is certified to have a -15/17 installed. The original owner may not have had this option in the type cert. It it is not I believe boeing also charges arround 100k o make he paperwork change to the actual aircraft type cert. for each specific aircraft. 7F had some airframes that had to have this done when they went to -17 engines.

You can also modify the -9a engines to a 15/17 via SB4500R8 at a shop visit.

GS
Sometimes all you can do is look them in the eye and ask " how much did your mom drink when she was pregnant with you?"
 
OPNLguy
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RE: 732: JT8D-9A To JT8D-15 Or -17

Wed Oct 04, 2006 12:29 pm

The 737-200 ADV(anced) aircraft with -9A engines we used to have at SWA had max takeoff/landing weights of 115,500 lbs./103,000 lbs. When I was with Air Florida, the 737-200s we had there had either -15 engines (119,500 lbs./105,000 lbs.) or -17 engines (124,500 lbs./107,000 lbs.), so I can understand Air North's desire to get more out of the airframe. As best as I can recall, there's no structural differences between the aircraft that allow these greater weights, and it's all a matter of the appropriate paperwork from Boeing, and how much you want to pay them for it, SkydrolBoy mentioned earlier.

These days, it's hard to tell which would be more cost-effective: getting a different aircraft with -15s or -17s already on it; acquiring and hanging -15s/-17s on it and getting the Boeing paperwork; or converting the existing -9s to -15s/-17s per the SB Greasespot mentioned and getting the Boeing paperwork.
ALL views, opinions expressed are mine ONLY and are NOT representative of those shared by Southwest Airlines Co.
 
2H4
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RE: 732: JT8D-9A To JT8D-15 Or -17

Wed Oct 04, 2006 12:55 pm




Quoting OPNLguy (Reply 3):
As best as I can recall, there's no structural differences between the aircraft that allow these greater weights, and it's all a matter of the appropriate paperwork from Boeing, and how much you want to pay them for it

That seems so ridiculous.

From a purely operational standpoint, is there anything even remotely dangerous about operating the uprated engines at the greater weights without Boeing's blessing?

Logically, that seems no different than a Chevy forbidding Corvette owners to exceed 45 mph unless a $2000 paper certificate is purchased. How does that piece of paper make the Corvette any more safe or roadworthy?

How in the world does that piece of paper from Boeing make the the aircraft configuration any more safe or airworthy?

I simply fail to see how this type of arrangement amounts to anything more than a racket....



2H4


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Fly2HMO
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RE: 732: JT8D-9A To JT8D-15 Or -17

Wed Oct 04, 2006 2:53 pm

Quoting 2H4 (Reply 4):
How in the world does that piece of paper from Boeing make the the aircraft configuration any more safe or airworthy?

As far as legal airworthiness is concerned, wouldn't putting in different engines than what it came with from the factory make it necessary to get a supplemental type certificate?
 
SkydrolBoy
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RE: 732: JT8D-9A To JT8D-15 Or -17

Wed Oct 04, 2006 3:36 pm

Quoting FLY2HMO (Reply 5):
wouldn't putting in different engines than what it came with from the factory make it necessary to get a supplemental type certificate?

That would be true if no 737's came from the factory with the uprated engines, but since some airframes did come off the line with the -15/17's, the type certificate already has the approval on it for the engines, you just need to get your a/c added to the list on the tc sheet like greasespot mentioned above.

Quoting 2H4 (Reply 4):
How in the world does that piece of paper from Boeing make the the aircraft configuration any more safe or airworthy?

Because Boeing has had their engineers study the effects of having the uprated engines on the a/c, hence if something were to happen to the airframe from using the higher thrust engines, that piece of paper would make Boeing ultimatly responsible if their was neglect on their part on the engineering of the a/c.
 
2H4
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RE: 732: JT8D-9A To JT8D-15 Or -17

Wed Oct 04, 2006 8:17 pm




Quoting SkydrolBoy (Reply 6):
Because Boeing has had their engineers study the effects of having the uprated engines on the a/c, hence if something were to happen to the airframe from using the higher thrust engines, that piece of paper would make Boeing ultimatly responsible if their was neglect on their part on the engineering of the a/c.

I see what you're saying, but my point is, Boeing engineers have determined that 737-200 airframe is indeed capable of handling the additional thrust of the uprated engines. Period. They did not determine that 737-200 airframes equipped with a piece of paper are capable of handling the additional thrust of the uprated engines.

In other words, in determining that the -200 airframes can handle the increased thrust, how have they not set precedent for all -200s?

If additional inspections were part of the approval process, I could understand the need for spending the money, but if the approval process is indeed the simple issuance of a piece of paper, it seems like Boeing is gouging the customer simply because they can.



2H4


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HAWK21M
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RE: 732: JT8D-9A To JT8D-15 Or -17

Wed Oct 04, 2006 8:59 pm

We operate the B732SF with JT8D-9A & a few with JT8D-17/17A.Obviously since its a freighter the latter powerplant is preffered.However a -9 to -9A intermix or 15 & 15A Intermix would involve just paperwork,trimming & a few Instrument upgrades.However to change to a higher thrust Engine would need the Manufacture to certify the Airframe can take the extra thrust.
regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
2H4
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RE: 732: JT8D-9A To JT8D-15 Or -17

Wed Oct 04, 2006 9:06 pm




Quoting HAWK21M (Reply 8):
However to change to a higher thrust Engine would need the Manufacture to certify the Airframe can take the extra thrust.

Pls elaborate.

(I've always wanted to ask you that, Mel)  biggrin 



2H4


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HAWK21M
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RE: 732: JT8D-9A To JT8D-15 Or -17

Wed Oct 04, 2006 9:18 pm

Quoting 2H4 (Reply 9):
Pls elaborate.

I like the question without the mark too  Smile

What I meant was the Customer would not be in a position to judge if the Higher thrust Powerplant would be tolerating to the Aircframe/Engine Mount attachments it was fitted on,hence a certifying Authority [manufacturer] would need to give that assurance.As they would have done the necessary test to confirm safety of the same.

regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
2H4
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RE: 732: JT8D-9A To JT8D-15 Or -17

Thu Oct 05, 2006 12:07 am




Quoting HAWK21M (Reply 10):
As they would have done the necessary test to confirm safety of the same.

Ok, that makes more sense....especially if each specific airframe must be physically inspected and approved.

Thanks, Mel!



2H4


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access-air
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RE: 732: JT8D-9A To JT8D-15 Or -17

Thu Oct 05, 2006 1:05 am

This is the same situation as I asked about in my thread about swapping props....
Swapping Propellers (Dowty Rotol) (by Access-Air Sep 6 2006 in Tech Ops)

I guess you just cannot interchange props or engines to enhance performance without special modifications...

Cheers, Access-Air
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