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Multi-Engine vs. Single-Engine

by Jeremy Cox 1. October 2005 00:00
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Recently I had a client ask me for my professional opinion regarding a specific aircraft that he was interested in possibly buying. He wanted to know: ‘What I thought about the Pilatus PC12 as a possible corporate aircraft for his company to own and operate?' He normally charters a BE400A and a CE525 CJ and has wanted to become less reliant on Charter by owning his own aircraft. He was very impressed by the cabin size, range, speed, and most impressive to him, the operating cost of the ‘big-bus' Pilatus. Other than having worked for the principle British investor who owned Pilatus in the 1980's in England, many, many lifetimes ago and during this period I got to mix with the then Pilatus executives and test pilots that where pushing the PC7 and the then new PC9, I really was not able to answer my clients question based on personal experience and therefore had to do some research. Well I must tell you that other than for the purchase price, the PC12 really stacked up against the King Air 200 for instance. The PC12 is longer than a King Air 200 (47.25 feet versus 43.75), has a slightly less wingspan (41.58 feet versus 54.50 feet), has approximately the same cabin length (16.90 feet versus 16.70 feet), has a wider cabin (5.00 feet versus 4.50 feet), more cabin volume in cubic feet (330 versus 303), carries more payload (with full fuel, 1,271 Lbs versus 395 Lbs), has more range (1,700 NM versus 1,600 NM), flies 10KTAS slower (265KTAS versus 275KTAS) and costs approximately 47% less to operate (Fuel @ $2.60/USG + Maintenance and Engine Reserves, $330/Hr versus $709/Hr.) The kicker is that used, it costs approximately twice as much as a King Air 200 to purchase ($2,300,000) versus ($1,200,000) and only has one Engine. Well after being made to ponder the significance of the comparison that I had just made, I thought that a visit to the Aircraft Accidents/Incidents page of the National Transportation Safety Board (NTSB) website which is (http://ntsb.gov/ntsb/query.asp), was in order to further my research. I performed the following queries of the NTSB database:

 

All events between 1/1/2000 to 10/27/2005 for ‘PC-12'

 

Then,

 

All events between 1/1/2000 to 10/27/2005 for BE 200

Here is what each query returned:

Pilatus PC-12 (Single Engine)

Type of Event

Number

Fatal Accident

2

Non Fatal

7

Incidents

1

Engine Failure (Fatal/Non-Fatal/Incidents)

2

 

Data from Amstat Corporation (http://www.amstatcorp.com/)

Active Worldwide

564

Active in the USA

370

 

 

Beechcraft BE 200 (Multi Engine)

Type of Event

Number

Fatal Accident

11

Non Fatal

21

Incidents

3

Engine Failure (Fatal/Non-Fatal/Incidents)

2

 

 

Data from Amstat Corporation (http://www.amstatcorp.com/)

Active Worldwide

2,521

Active in the USA

1,153

 

Now let's crunch these numbers:

There are 1,957 More BE 200 Aircraft in current operation Worldwide, than PC-12 Aircraft (2,521 – 564 = 1,957); Which makes the BE 200 346.9% more prolific Worldwide than the PC-12.

 

There are 783 More BE 200 Aircraft in current operation in the USA, than PC-12 Aircraft (1,153 – 370 = 783); Which makes the BE 200 211.6% more prolific Stateside than the PC-12.

According to its website, the NTSB is an independent Federal agency charged by Congress with investigating every civil aviation accident in the United States and significant accidents in the other modes of transportation, and issuing safety recommendations aimed at preventing future accidents. The Safety Board determines the probable cause of all U.S. civil aviation accidents and certain public-use aircraft accidents. Additionally the NTSB is responsible for maintaining the government's database of civil aviation accidents and also conducts special studies of transportation safety issues of national significance. The NTSB provides investigators to serve as U.S. Accredited Representatives as specified in international treaties for aviation accidents overseas involving U.S. registered aircraft, or involving aircraft or major components of U.S. manufacture. The NTSB also serves as the "court of appeals" for any airman, mechanic or mariner whenever certificate action is taken by the Federal Aviation Administration or the U.S. Coast Guard Commandant, or when civil penalties are assessed by the FAA. Since I don't have statistics for the PC-12 and the BE 200 from any country outside of the United States, other than several NTSB Reports for foreign PC-12 and BE 200 aircraft that they investigated, it is only right for me to only use the statistics as they apply to the domestic fleet, therefore:

The accident statistics caused by Engine Failure that apply to the PC-12 and the BE 200 are as follows:

 

Since the beginning of 2000, for 370 PC-12 Aircraft there have been 2 accidents attributed to Engine Failure.

Since the beginning of 2000, for 1,153 BE 200 Aircraft there have been 2 accidents attributed to Engine Failure.

Which equates to:

2/370 = 0.0054 x 100 = 0.54%. Therefore the Risk Factor of having an Accident in a PC-12 due to Engine Failure equals 0.54%.

2/1,153 = 0.0017 x 100 = 0.17%. Therefore the Risk Factor of having an Accident in a BE 200 due to Engine Failure equals 0.17%.

0.54/0.17 = 3.176.

Therefore the likelihood of having an Accident in a PC-12 due to Engine Failure is more than three times that of a BE 200. Obviously further study needs to be made by including for example the Socata TBM 700 compared to the King Air C90B or Commander 690B, and the Piper Meridian against the Mitsubishi MU2 or Piper Cheyenne, etc. etc. I don't have time to do this, but I do believe that I am on to something here which pretty much confirms my own convictions in regards to Single Engine Turbine and Multi Engine Turbine Aircraft, i.e. for anything other than Flight Training or Single Pilot missions, a Multi Engine Turbine Aircraft must be selected over a Single Engine Turbine Aircraft! Stay with me on this. The statistical numbers as they apply to Piston powered Aircraft will, I am guessing, be the exact opposite of Turbine equipment. I believe that I actually read this to be true in a recent report that the Aircraft Owners and Pilots Association (AOPA) issued, that compared Single Engine Pistons to Multi-Engine Pistons (Training, Complexity, Speed and Weight were the demons in this report.) Virtually every one of us starts our piloting careers in a Single Engine Aircraft. However as we progress through our ratings and gain more experience, most of us, if we make a career out of carrying passengers either part 91 – corporate, or commercially, will end up flying multi-engine, turbine powered aircraft. It takes training, experience, usually ratings and more training to fly turbine aircraft, regardless of how many ‘donkeys' hang from it's nose, wings or tail. The insurance companies have made sure of this, therefore the argument that a Single Engine Aircraft is safer for a private pilot to fly compared to a Multi due to less complexity and issues with asymmetric thrust, etc. just does not wash with me when we are discussing turbine aircraft. Unless of course, you choose not to carry any insurance, then all bets are off. I know that an almost fifty percent lower Direct Operating Cost per Flight Hour is damn attractive to a business owner and corporate accountant, but consider this scenario: You are flying high over a thick overcast that extends to the ground, it is night and you are currently overhead somewhere really hospitable (NOT! - for a forced landing, that is) like the Rockies or Adirondacks and your engine begins to give you unusual and expensive noises along with rapidly failing performance. I bet you that right at this very moment there is no amount of money too much, that you or your passengers would not be willing to pay for a second engine, assuming of course you are in a Single Engine Turbo-Prop Aircraft and the only engine that you have got is failing!

I know that I am setting myself up for some real abuse from anyone that works for, or currently owns a Pilatus, Socata, Piper, or Cessna, Single Engine Turbine Aircraft, but I could not with any good conscience respond to my client with the words: "Go for it, a Single Engine Turbine is the way to go as your corporate aircraft," because I personally don't believe this, and further more I feel that the Risks far outweigh the Cost Benefits of operating a Single Engine Turbine Aircraft for passenger operations over a Multi-Engine Turbine Aircraft.

Okay now it's your turn. Flame me! Please post your comments below and try not to call me too many nasty names!

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Jeremy Cox



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