Merlin III and AC690 operating figures.

[MCKES]

Anyone have experience operating either Merlin's or twin commanders? Some help with some operating figures - Loads, fuel burn, planned Tas, direct operating costs etc would be greatly appreciated. Also interested to hear about maintenance issues with either machine.
Thanks in advance.
Also has anyone used the Conklin de decker manuals for operating costs?

[tail wheel]

I think only DCA operated both Merlins and Turbine Commanders. In general commercial operators steered clear of both aircraft types and early versions of the Garrett engine.

Some of the Conklin & de Decker (https://www.conklindd.com/Default.aspx) variable (or direct) operating costs appear to be higher than actual aircraft operating costs. To the direct costs one must add the fixed (or indirect) operating costs, resulting in an extremely high total operating cost in some cases. However, the costs they give are a good guide.

[chimbu warrior]

Look around, and you will see that this sector in Australia is dominated by the Conquest II. A great machine, especially with the Dash 10 engine upgrade.

[Corkey McFuz]

I can't speak for the Merlin but I like the Commander. Its lovely to fly and very simple. Usually will tas around 270 ish (depending on config), 3450 useful load, 2550 gas with an average burn of 500 an hour but obviously varies. I've only flown the original -5 version but the dash 10 are very popular and depending on configuration will give an honest 300+ tas on a similar burn. Goes like a shower of **** apparently.

The commander 1000 is the real mother ship. Major problem with them all is there is bugger all room inside...

[MCKES]

Thanks Guys, Tailwheel you seem to be right about the Conklin figures they do seem high although you need to read there section on what they include in that figure.
I have figures available already for B200 and C441, just though I would look at what else is there.

Given this mission as an example what would people recommend.
Time is money
Efficiency is key
Low initial outlay is a bonus.

750nm Sector preference for single leg, no fuel stop.

4-5 Pax @ 100KG + 10KG bag. + Pilot.

Can be anything SE Turbo prop, Piston, no restrictions.

[AdamFrisch]

The 690-800 to 1000 series are real long range travellers. Over 2000nm range. The dash 10 engines are rock solid and more fuel efficient than PT6's, plus have much higher TBO.

[LeadSled]

MCKES,
Talk to Winrye Aviation at Bankstown, Brian Chadwick, about Merlin operating costs. They have rebuilt the two DCA Merlins, and put then back into service, (well, one and one about to go) plus have a lot of experience with them.
Both aircraft have very long legs.
The Merlin is a bit more roomy, but does not have anything like the field performance of the Commander.
Do a very thorough inspection around the nose wheel area of a Merlin, repairs to serious damage in the area is common, leaking fuel from the centre section is also a good indication of heavy landings.
Don't even think about either, unless they have been upgraded to at least -10 engines.
In my opinion, a Grand Renaissance Commander (effectively re-manufactured) is the best way to go, look up the US web sites for Twin Commander Corp., that will give you leads to the major sources. Twin Commander Aircraft LLC (http://www.twincommander.com/renaissance.html)
GAM are the Australian experts on Commanders.
Tootle pip!!

[tail wheel]

750nm Sector preference for single leg, no fuel stop.

4-5 Pax @ 100KG + 10KG bag. + Pilot.

Can be anything SE Turbo prop, Piston, no restrictions.

Why get involved in orphan, old, out of date, high operating cost aircraft?

What is wrong with a logical, cost effective solution - a Cessna 208 Caravan?

[an3_bolt]

Just a bit of lateral thinking / dark horse:

[QUOTE]Given this mission as an example what would people recommend.
Time is money
Efficiency is key
Low initial outlay is a bonus.

750nm Sector preference for single leg, no fuel stop.

4-5 Pax @ 100KG + 10KG bag. + Pilot.

Some might laugh and scoff at it but the C550 might suit......if want single driver S2 or 2SP.

Flew a C550 for a while with the nosewheel spin up kit. Good performance and comfortable. Was a great introduction to jets for me - simple and honest machine.

Imagine devil is in the detail - access to good maintenance, utilisation rate, owners "emotional" wishes, etc.

If it was me - I would be crunching numbers on all the ones you have mentioned as well as this. Numbers may or may not stack up.

Good luck

[hiwaytohell]

750nm C208 vs AC690 = 4h 45 vs 2h 45 plus pressurisation

Different tools for different jobs. On a 750 nm sector the 690 really excels and having experience with both types the 690 would have better economics per nm on any sector over 250nm.

Both great aircraft, but very different capabilities. Although the 690s are getting on a bit they are still a great aircraft if they have been properly maintained... also like the Merlin look out for fuel leaks because they have a dozen or more tanks and the outboard ones tend to perish as a lot of short sector operators only fill the centre tank.

And the 690 is absolutely beautiful to fly even if the cockpit is a bit cramped!

[MCKES]

Thanks guys for your input, all valid. I will be talking to some operators and maintenance organisations soon, just wanted the general pilots opinion first. C208 is a great machine, way too slow for this mission though. PC12 is another good one, but out of the price range, may be an option but would prefer a lower initial investment. The AC690 seems to meet the profile, fast with the legs, good load, just maintenance I am worried about. Short field is not a concern all large sealed strips.

Also AN-3 I know where you are coming from with regards to the jet, it would be a consideration though I think unlikely due to utilisation of the aircraft on shorter sectors as little as 150nm as well. RVSM would also come into it.

Thanks Guys. :ok:

[Howard Hughes]

750nm Sector preference for single leg, no fuel stop.

4-5 Pax @ 100KG + 10KG bag. + Pilot.

Can be anything SE Turbo prop, Piston, no restrictions
A 750NM sector screams jet to me! Why spend three hours on your bum when you can spend two?

If you're gonna get a clapped out old aircraft, why not make it a jet? (http://www.controller.com/listingsdetail/aircraft-for-sale/MITSUBISHI-DIAMOND-1A/1983-MITSUBISHI-DIAMOND-1A/1249081.htm?) :ok:

[MCKES]

If you're gonna get a clapped out old aircraft, why not make it a jet?

I like your thinking Howard:}

[kalavo]

Conquest would easily do that.. with -10's you'd probably find it can do it with return fuel as well depending on the empty weight.

[Torres]

The AC690 seems to meet the profile, fast with the legs, good load, just maintenance I am worried about.

Just a touch of an accountant in the pilot! :ok:

If the turbine commander is such a wonderful performer and money maker, why did only a handful come to this part of the world, many to DCA, very few in charter, none in RPT?

It is a 1944 Ted Smith design. There was fifteen (15) different turbine Commander models (and 16 different piston engine models), the "youngest" must be at least 30 years old! Most of the manufacturers are out of business.

From 1961 to 1993, 24 aircraft crashed when spar failures caused the loss of the wing in flight (including a few in Australia). 35 more spars were found cracked during inspections. The expensive spar inspection program continues.....

There is no such thing as a cheap aircraft. If you must buy an aircraft, at least buy something that has proven service and productivity in Australia, has a manufacturer that is still in the aircraft business, has local parts availability and hopefully is younger than the pilots flying it!!

You will have two days of great joy when owning 30 plus year old, old technology, tired GA aircraft: The day you buy it, and the day you finally get rid of it! :}

[AdamFrisch]

You should also look into the MU-2. You can not get more bang for the buck. The Marquise has great range, fast, cheap, built like a tank and are still fully supported.

[Trojan1981]

I know little about the 690 or the MU2 (though both look like interesting types) but the one that continues to be a big winner in charter is the Conquest. It's cheaper than the King Air, damn near as fast as a C550 and able to operate from short strips. They also tick all the insurance boxes for your bigger clients.

[Jamair]

Like Torres said- There is no such thing as a cheap aircraft. If you must buy an aircraft, at least buy something that has proven service and productivity in Australia, has a manufacturer that is still in the aircraft business, has local parts availability and hopefully is younger than the pilots flying it!! Seriously, if you cannot afford to buy and operate a PC12, you will not afford the purchase and operation of any of the listed antiques. The initial price is the least of your worries.

(and how are you goin Torres?)

[F1-69]

I have 2 Merlin 3b, typical loading 2000# in the cabin which brings you to your zfw then 2100# of fuel which puts you at your ramp weight and at a tas of 290 and 600pph at low alt and 500 at high alt fuel burn, no wind with legal reserve is around 950 miles, not to shabby, and if you trade people for gas it can do lax to jax non stop

[F1-69]

That's coast to coast USA for the foreigners

[MCKES]

Seriously, if you cannot afford to buy and operate a PC12, you will not afford the purchase and operation of any of the listed antiques. The initial price is the least of your worries.

I'm afraid that's not entirely correct. It is for the same reasons we still see the GA fleets average age continuing to increase. Initial outlay - especially in regards to contract based work where we are able to calculate the life cost and write the aircraft off over the period, the initial outlay can play a large part. And none of the aircraft looked at have been the "low end" ones. If they are of age they have been refurbished to an acceptable standard and have a higher variable cost budgeted for operation.

As people have said before purchasing a 1.5m aircraft compared to a 5m dollar one. 3.5m is either a lot of maint or a lot of flying.

[Jabawocky]

How much does it cost when the aircraft is "offline" for unscheduled maintenance chewing into that $3.5m

This is where accountants get it WRONG. And no amount of arguing ever works for the majority of them.

If you are prepared to spend some of that $3.5m on maintenance plus the cost and PMO finding alternatives at short notice, when you sum it up over the first couple of years all the tears and most of the money will have you in the same financial position, and still with a ****box.

Everyone should have heard this before, buy your last aeroplane first. It is cheaper.

PC12 is your answer. Plenty available around the world.

I noticed RNZAF B200 Kingbears are on the market and if you look into them they may be viable. Only about 10,000hrs I think I saw. Aviation Trader has them in a big advert.

[THE ORACLE]

MCKES,

Here, here....I too am with you on your latest comment/assessment.

The Merlin IIIB and the AC695B (Gulfstream Commander 1000) were the ultimate developments of each type, with the Merlin fuselage then being stretched for the Merlin IV and becoming the Metro series of commuter airliners.

Metal fatigue issues associated with the smaller Twin Commanders (both piston and turbine powered) were not such a concern for the AC695s due to the higher weights and extra metal added to the airframes. Additionally the AC695 has a simplified system of fuel cells to deal with the fuel leaks prevalent in the 690 series.

The "Renaissance" program offered for the Twin Commander series has been mentioned in an earlier thread. This program, as well as offering a 'nose to tail' fueslage and systems renovation, can also provide a complete 'glass' upgrade for the avionics, thus saving some more weight and reducing future maintenance costs (the AC695B's all came with a 3 tube Collins EFIS, which is becoming expensive to maintain/replace).

The Dash 10 engines (standard on the AC695) can be zero timed at the owner's request with a new 5,400 hour TBO. Significantly the Dash 10 conversion (an upgrade for a 690/840 airframe) eliminates the need for SRL computers which can be a problemmatic.

Although the Merlin IIIB is a great aircraft in its own right as ably described by F1-69 it does not have the short field performance of the Commander, which in my view might give the Commander an edge.

Comments concerning problems with buying what has been described in this thread as "antiques" are interesting. It is true that G.A. aircraft aren't built to "Transport Category" maintenance standards and there are problems to consider with ageing aircraft.

However, most of the Commander 1,000's and Merlin IIIB's were /are operated as corporate aircraft and haven't accrued that much flight time over the years.

Consider this. There are many cheaply available (compared with the cost of a new aircraft), proven low time high performance aircraft which were designed for 2,000NM range, at 300+ KTAS and with a cabin capacity for up to 9 passengers.

At least one type certificate holder (Commander Aircraft LLC) offers a service where the airframe can be stripped to bare metal, inspected (NDT) to remove, or confirm the absence of fatigue, bending or stress fractures. The aircraft is then renovated inclusive of new current technology powerplants, systems, soundproofing and avionics, etc.

In this case Commander LLC also offer a world wide parts supply chain and AOG support, to assist maintenance organisations (large or small) to cost-effectively maintain such aircraft. As mentioned in an earlier post Winrye aviation in NSW reportedly have re-built 2 Merlin aircraft and there are many of this type still flying with a host of spares available both locally and on the world market.

There are several other renewal programs such as the Turbo Royal Duke, Turbine single Cessna and Beech programs, Cessna 208 "Blackhawk" conversion, etc.. All of which have provided lower cost, performance competitive alternatives to buying a new aircraft.

Jabawocky, there is no denying the PC12 is a great aircraft. It has found a real niche world wide including Australia. The NG is a much more capable development on the original and is priced accordingly. The operating cost of PT-6 powerplants, however, (inclusive of maintenance burden) can't compare with the Honeywell/Garrett TPE331 alternative.

For example a PC12NG at high speed cruise (280KTAS) will burn 58.83 USG per hour in cruise at Flight level 200. In comparison, a Commander 695 cruising at flight level 350 will burn 75USG per hour (total for both engines) and cruise at 302KTAS. Due to the 30KT speed advantage the Commander will effectively burn less fuel overall for a typical mission profile and accrue less overall engine time for the mission than the PC12-NG going flat out.

Although the Commander has two motors, the simpler design of the Honeywell/Garrett powerplant affords a higher TBO (5400 hours) than the PT-6 and results in a lower maintenance burden. Yes, there are still two motors to maintain and overhaul, compared to one, but the economics in favour of the Honeywell/Garrett powerplants overall are compelling!

In part this is the reason why Kestrel Aircraft has recently dumped the PT-6 in favour of the TPE-331 powerplant as Kestrel contines to develop their aircraft for the market.

The Oracle

[Trojan1981]

Jabawocky said

PC12 is your answer. Plenty available around the world.

Only problem is, insurance/audit requirements for the bigger customers dictate no singles of any kind. I just had a customer book a Learjet over a PC-12 on a 45 min sector for this reason. No negotiation, the insurance company refuses to cover travel in any singles of any kind and this is backed by the organisation's policy.

Stupid as it may be on most occasions, they will pick a light twin (and insist on two pilots) over a Caravan or PC-12.

[AdamFrisch]

Planes are not like cars. They don't follow the rule that if it's newer, then it breaks down less. I'd say there are as many Cirri or Matrixes in for repairs at my shop as there are 30 year old legacy twins. Every part of a good utilised plane in 135 ops has been replaced or been attended to over a 30-40 year lifespan. It's like cell renewal - they're essentially partly new airplanes. Now, a Commander or a MU-2 might be something to avoid if they weren't supported, but both of these have stellar support and new parts are readily available and still manufactured.

[Al Fentanyl]

MCKES, you have had some solid advice from folks that I know, who have personal experience in doing what you are asking about. Tailie, Torres, Jabba et al have been there, done that - some on a grand scale!

The aircraft you talk of are undoubtedly interesting, nice to fly, sexy, whatever; but there are reasons why they are no longer produced. It is a mistake (that I have made in the past) to buy a particular aircraft based on 'want' rather than 'need'. If that is your thing, that's OK; just don't try to make it into an economics argument. Accept that you are using heart rather than head, and continue open-eyed down that path. Don't get me wrong, I am not having a go or criticising you; I love that you want in to owning an aeroplane.

I wish I had listened to Tallie a few years back and leased or crossed-hired a new Baron instead of buying.

You can get a PC12/45-10 for a bit over a mil, a B200-41 for well under a mil, a Citation 500 for maybe 1.5; all current production aircraft and all will fill the role you have described.

I wish you well with your eventual pick & hope to see photos on here!

[MCKES]

Guys, don't get me wrong, it will definately be a head and not heart decision if we get the go ahead. And the aircraft we have been looking at have in fanct been the pc12 and beech kingair series anyway. The ac690 and Merlin's where just a consideration, it would be unfair to discount them and not look into them further. Al just over 1m for a pc12? There is one offered at around 1.3 with 10k + hours otherwise market price for anything reasonable is around the 2-2.2m mark. Conquest as people have mentioned is a very good machine however the cabin is not attractive to pax (who are very important in the final decision) and has been discussed, much the same is the Merlin and Commander cabin. The decision is still pending at present and will be a slow one at that. No one is in a hurry to rush in, and when the we do make one it will be the right one for the situation.

And thanks once again for everyone's help. It's much appreciated and great just to bounce certain ideas around and get some opinions you may not necessarily get from someone either selling or involved in a particular aircraft.

[Jabawocky]

Oracle

Maybe I am tired....or missing something but the two speed/burn figures you quoted show the twin TPE's using 20% more MPG than the PT6.

Now I get the TPE concept and understand the Kestrel thing.....had a really close look :) so unless there is a typo it does not add up.

Trojan
The deal here is a S/E is not an issue. So a PC12 is on the cards.

I think a PC12 or B200 work well, otherwise the RFDS would be using something else! I know folk who operate the PC12and it works very well for them indeed!

Lease a sub 10 year old one perhaps?



Buy your last aeroplane First!:ok:

[THE ORACLE]

Jab,

Thanks for the query. I made as few assumptions based on "M"'s original mission profile of 750NM and having flown both powerplants, I assumed the PT-6 powered single would not be run continuously at high speed cruise for the purposes of reliability, overall economy and optimised maintenance accruals. Whereas the AC695B at altitude, cruises at a genuine 302 KTAS regardless (near the same speed as a King Air 350).

Assuming the mission is run fairly frequently (a couple of times each week) the AC695B would take 2.48 hours flight time for a 187.5 USG fuel burn and the PC-12 would take 2.88 flight hours (@260KTAS) and burn approximately 156 USG. And yes the single will burn 20 percent less fuel per sector than the legacy twin.

However, depending on the payload the AC 695B might regularly be able to take return fuel (design range with 7 passengers 1,400NM) and the PC 12 might need a fuel top up at the out port differential fuel price (design range with 3 passengers 1573NM). Outport differential fuel prices at non Capital City locations (if that is where "M"'s mission flies to) makes fuel expensive to purchase and needs to be considered.

The cost of fuel differential pricing, together with the 0.40 flight hours saving per sector at 3 missions per week for 48 weeks (allowing for an annual holiday) results in the AC965B using 115.5 less airframe and engine propeller maintenance hours overall per year than the PC-12. All of which combined makes for a compelling argument favouring the Commander over the Pilatus.

You could of course shave the PC-12 flight hour margins by running the PT-6 'flat out', but the increased fuel costs at the out port from continuous high speed cruise, combined with the almost inevitably increasing maintenance burden on the PT-6 powerplant, would tip the balance further towards the AC695B.

Considering the distances involved I do think a small jet would provide a more cost effective answer to "M"'s mision requirement.

Jets burn more fuel than turboprops, however the overall maintenance burden, en-route charges, etc. with a small jet would be less over a 750NM sector and if the mission did fly the 3 returns per week that I have assumed, at the end of the year the overall costs of running a jet compared with a turboprop might prove to be less.

A small jet such as a Raytheon Premier 1A (single pilot and 7 passengers) at high speed cruise (450KTAS) would flying the 750 NM mission 3 times each week for 48 weeks in the year for 235 less flight hours than the AC695B and although the jet's fuel burn is greater (approximately 225 USG for the sector) there might be a substantial cost saving overall due to the reduced flight hours, etc..

The Oracle

[Jabawocky]

It is a good "mental Business plan" we are doing here.

But can I ask another, with the PC12 over the Commander, the fuel burn and times etc....you mention the extra maintenance hours, but is that 2 x TPE maintained for less than one PT6....adjusted for the hours flown of course?

do agree a small jet be it the Beech or a CJ3 or Phenom might be a better option, however, no mention of jets in the OP request.

Anyway your analysis is interesting indeed.

He should get a Phenom300, and a PC12, and a C208. One for every occasion :}

[gaunty]

What Jamair said:ok:

As for MU2 :ugh::ugh::ugh::eek::sad::mad:

[THE ORACLE]

Jab

Great to hear from you again. True with the legacy twin there are two motors and propellers to overhaul. The TBO for the PT-6 in the PC-12 is at 3,500 hours with an HSI at 1,750 hours and propeller everhaul every 4 years.

Honeywell Garrett offer a couple of options on their TPE331-10T overhauls. Either you can do option A) - an HSI at 1,800 hours or an HSI and gearbox inspection at 3,600 hours allowng an overhaul at 5,400 hours, or option B) with an HSI at 2,500 hours and a combined gearbox and powerplant overhauls at 5,000 hours.

Either way the TPE331-10T combo can productively remain on an airframe for either up to 1,900 hours more per pair (option A) or 1,5000 hours more per pair (option B) than the PT6 equivalent. Which is the point that I was making. Propeller overhaul intervals would be comparable for both aircraft and at a nominal average cost (usually $4K USD).

Full lease costs on any of the jet aircraft you mentioned would change the equation entirely. Current residual values for a pre-loved Raytheon 390 run at $3Mill to $3.5Mill USD. Should MCKES decide to explore this option he might consider negotiating a damp or wet lease price for a block of flight hours from an interested owner to cover commencing the proposed work. If the 'books balance' he could take his revenue figures to the bank and have them partner him in an aircraft lease. Currently there are 2 Aussie registered Raytheon 390's for sale and someone might 'do the deal'.

I agree with Gaunty's thoughts on the MU2. Although there have been a high number of accidents over the years it remains well supported and owners/ operators have a dedicated website to assist with preserving the Mitsu. Despite the reputation it can be a safe aircraft, however the cost of CASA compliance in this regard might be prohibitive.

The Oracle

[gaunty]

Oracle,

The MU2 wasn't in itself a "bad" aircraft it just fell into "bad" company, exacerbated by the performance problems bought on by a fatal weakness with the wing loading comparable to Lears, without the grunt and a unique flight control system with a back to front Vyse Vs relationship.

In the early eighties as a result of this accident history it's used value was around 50% of Conquest, King Air.

Attracts bottom feeders like blood in the water. And so it goes.

[AdamFrisch]

Since the FAA imposed SFAR or "type rating" on the MU-2, its accident rate has dropped below Commanders and King Air's. It attracted the wrong operators and pilots because it was cheap, but there's nothing wrong with it. In fact, they're tanks. I don't think there's any recorded incident of structural failures in the MU-2 fleet - not something you can say about any of the others.

[THE ORACLE]

Adam, "G",

I agree with all your comments and I am well aware of the type rating requirement and the positive effect it has had on the statistics, but I kept my comment on the 'Mitsu' short in order to maintain the focus on responding to 'Jab's query.

In supporting both your comments, I suppose it (the Mitsu) proved in the most costly way that safey in aviation comes at a cost and that is is naive in the extreme to assume at face value that a cheaply bought turbine twin automatically translates to a safer operation.

The Oracle

[gaunty]

Amen.

But it is only a short step to the other legacy turboprops.

We've moved on since then, actually a lot.

Throwing money after one of them with little or no prospect of its return has to be part of that equation.

On thread, you would have to class the Merlin and AC690 in the same category so why bother.

Old but true the saying in this business is "pay now or pay later".

You can now buy a well maintained C550 with all the fruit for around the $1m.

Cost per nm is not all that different and you have Part 25 transport category safety without having to take your chances with a pilot (usually not so experienced) getting it wrong with the turboprop.

You won't get me on board one anymore unless the pilot can show me the single engine take off gradient for the day against the TODA/STODA. And then only after a rigorous cross examination of his experience level and intended actions.

[PLovett]

Ah gaunty.................it wasn't all that long ago I remember you posting on the delights and virtues of a Conquest. It appears your sojourn in Part 25 machines has changed your perspective. :}

Actually I do understand what you are saying but I just jealous that you have been running around in Challengers and GIVs'. :ok:

[Stationair8]

Good to see you back on pprune, Gaunty!

Bet you still like to strap your touche into a nice Conquest, with Dash 10's just for old time sake!

[gaunty]

PLovett me old. Conquest, still legends in their time.

Gross weight take off straight to FL350 start cruising 290KTAS FF can't remember exactly but <400pph. 2100nm range. Had the pleasure of many non stop coast to coasts both ways.

But that my friend was back in the late 70's and early 80's.

Cessna had to stop building them because they were predating Citation sales, that's how good they were. Over a 3-400 nm sector it was a close run thing.

Always was headed to Part 25 machines but Australian two airline policy pretty much put paid to them in any meaningful way. We actually had ordered an HS125 4BRA for charter in the early 70's but Customs stopped that. Tom the Cheap and Bell Bros took delivery of theirs as they were for PVT ops.

The two airline policy is where the idiot Senior Commercial license, (you could not hold an ATPL or Class 1 or 2 instrument rating unless you were employed by ine of the airlines) came from as well as the single pilot command instrument rating.

Been a bit busy for the last 5 years. Trust me financially they are not for the faint hearted.

Stationair8. -10's with Black Macs, maaaate.

Back on thread if they are serious about legacy turboprop they should add the Conquest to the top of the list. Bobby Douglas or John Tilley will know where the good ones are:ok: