Quick question. What do people think of the garrett tpe331’s in terms of reliability, cost at hot section and overall operating costs when compared to pratt pt6’s.
People think Garretts are LOUD!!!
And more expensive.
…and burn more gas.
What!:shock:
The PT6 burns more fuel for the same power. The TPE331 is a better engine but does cost more at overhaul time & doesn’t like sloppy mechanics/mx.
The PT6 is bullet proof, simple for any mechanic, cheaper at over haul but burns more fuel/HP.
1 Like
Ditto 185Driver… The TPE331 is more efficient than the PT6. But, it is a little more complex in addition to its direct drive gear-box. The TPE331 is also temp sensitive and is not forgiving to an inattentive operator.
Ditto ditto those guys. They are both good engines. I find that it’s more about the aircraft/engine combination. Example, Turbine Otter with a Garrett…Good. Kingair with a Garrett…Bad. I wouldn’t worry so much about the engine as I would the aircraft they’re attached to.
Thanks for all the replies. I have seen numbers on vref to the tune of 250k for overhaul of pt6 vs 180k for the garrett. Also, tbo on the garrett is 5400 hrs vs 3600 for the pratt. Does this sound accurate?
triple ditto, after being around J31’s for 5 years and Beech 1900s for another 5, I can tell you with surity, and slight hearing loss, that those Garretts are screamers, while the 1900 is a moaner.
You got me…I just looked up my research from a few years ago when I was considering Turbo Commanders and you’re right. In fact, my notes directly show the Garret’s burning about 5 gph/hr more than the PT6 at the same power setting 
I have flown -5 garrets and -10 in 690 commander and 1000
690commander 331 -5 goes 250-260 kts betweeen 18-20 thousand feet summer and 20-22 thousand in winter burning 500 pounds a hour in cruise= 73 gallons hour and 600 pounds and hour first hour =88 gallons
hot sections every 1800 hours 5400 tbo. They can be expensive if not flown consative with a cap around 106k. my first hot was 98k including inspection and parts on both engines. most damage found in hot section inspection is from starting engines with weak batteries, so i’ve been told.
i believe you have to do a gear box inspection on second hotsection
1000 commander 331-10 goes 300kts at 28,000 feet burning 440-480 summer/winter pounds an hour in cruise=64 gallons. first hour = 600 lbs an hour =88 gallons.
i am on 5000 tbo. one hot section at 2,500 and no gear box inspection required. 30-35k average hot section for both engines. mine was 60k for both engines because i had lot of erosion on one t wheel. supposively from flying up to 32-35 thousand feet will cause that, but plane is not rvsm’d now. I know someone who’s hot sections on a -10 commander totaling 20k for both engines.
garret= push power levers foward=instant power. loud outside but don’t notice it inside. pull the power back to king air speed and you won’t even notice the noise, lol
Cswan, thanks for your insight. Was wondering if there is any other good info on the 690-5 as that is what I am seriously considering upgrading to. What are operating costs, 150hr inspections like, heard it is somewhat of a complex plane. What do you think about spar issues. Any info greatly appreciated. PM me if you like.
Exactly what is “Kingair” speed? The numbers you quoted for the 2 Commander aircraft are Kingair speeds. 260 kts is a slowish B200 block speed, 300 kts is a B350 cruise. Perhaps you’re thinking of old, old 90 series Kingairs?
I think you might be incorrect about the engine fire reference. There was a metro that had a brake fire that, due to it location when retracted, took out the whole nacelle…but there has never been an inflight engine fire of a tpe331 that i know of…anyone have an NTSB to clarify?
As for power i remember working the numbers while waiting (that is what a pilots real job is) and the TPE331-10 is 13 or 14% for efficient per hp than a pt6 in flight
shoot…I just notice how old a thread this is… 
I just wanted to add my $0.02. I’ve never flown a Garrett powered aircraft, but all my A&P buddies whine about them. Apparently they are inherently fussy to work on, or just a PITA in general maintenance wise.
I’ve flown a few hundred hours on different PT6 engines, and I’ve not had any major issues with them, but it was all in military aircraft that have had contract maintenance, so my experience with the P&W are limited time-wise.
Just to set things straight, the Garrett costs less to operate than a PT6. It burns less fuel and costs less to overhaul. It is more responsive than a PT6 as well because it is a common shaft throughout the engine. If you would like documented proof of this let me know and I will get it to you. The two negative things about the Garrett are that it is noisy outside the aircraft while on the ground and it is easier to hot start.
331 garrets are loud indeed, but that’s from the outside looking. I also co-sign with 636ironhead’s post. I’ve been around an A100 with -60A’s and a B100 with 331’s and you could could definitely hear the difference!
Garret > Prat.
The tpe331 is more fuel efficient.
As an A&P who has worked both engines I can say that I`ve met my share of pilots who have flown both either under Part 91 or 135. The- 91 Garrett operators seem to fair better if operated by the same pilot most of the time. The -135 operators (if multiple pilots) seem to degrade the Garrett by different operating procedures. Mainly in the number of hot starts. On the other hand the Pratt seems to fair well with multiple operators in either catagory. Hot section inspections are rather simple to perform with the Pratt but the Garrett can be a challenge. So I guess one should weigh the difference in the fuel burns between the two and then weigh what happens at the inspection time for a hot section. By the way we mechs affectionately know the Garretts as “Claymores” as that seems to be what happens with them when they give up.