Single-Engine 135

The rules may have changed but the reality hasnt. Approving a single-engine piston for IFR charts ops is all but impossible.

Pilots lounge rumor has it that the FAA has approved single-engine IFR for Part 135 passenger-carrying on demand operations. On demand means passengers wave money at pilots and demand to be taken somewhere.

Pilots, an easy lot when it comes to money, might be tempted to grab the money and fly. Weve heard from several readers who are thinking about sinking big bucks into a Saratoga or a nice used A36 Bonanaza, figuring to offset the expenses by putting the airplane on a charter flightline.

We wish em luck. Potential single engine charter operators are finding out there’s more to putting that Cherokee Six into charter service than simply buying an ad in the Yellow Pages. FAA approval of SEIFR 135 passenger carrying operation is not a given and, except for turbine singles, it probably cant be done, even though recent changes to FAR Part 135 seem to indicate otherwise.

The Legalities
To begin the certification quest, operators who wish to hold out to the public as an airline, air taxi or charter must refer to FAR Part 119, mostly to find out what FAR actually applies. Generally, operators who fly a scheduled service and sell tickets slip into the maze of Part 121.

If, however, the operator wants to simply be available for on demand charter operations, then a Part 135 certification is required, called an ATCO for air transport certificate of operation in the lingo of commercial flying. Its possible to have scheduled Part 135 in non-turbo jet aircraft under nine passengers and less than 75,000 pounds but that doesnt apply to single-engine considerations.

In the past, if you wanted to carry passengers for hire in IFR, you needed a twin. That still may be your best choice. In fact, it may be the only choice. The FAA will be relatively cooperative in this arena because they know the ropes, what papers to submit to higher HQ and what checkrides to give. These guidelines have existed for years and any FSDO worthy of the name can do these approvals in its sleep. (Some, in fact, do.)

Multi-engine airplanes are relatively easy to certify for Part 135, partly because they usually come equipped with dual vacuums and dual electrical systems and the accepted philosophy has been that dual is doubly good. Lately, rebel forces have cried out that single-engine IFR is just as good; some might dare say better.

Modern singles such as the Malibu, Mooney or Bonanza, the reasoning goes, are far superior in the IFR world to what was grinding around 30 years ago. They have dual vacuum pumps, back-up alternators, second batteries and, increasingly, certification for flight in known icing.

You can decide for yourself whether two engines are twice as safe or not. Thats an argument for angels and statisticians, not mortals. For years, singles could be used for hauling cargo for hire-IFR or VFR-everything from canceled checks to almost canceled chickens.

The thinking was this: The airplanes and pilots are replaceable and the cargo doesnt write to Congress after a wreck. The voting public, however, needed two motors in IFR for hire. A murky exception existed for single-engine VFR Part 135 operators to be allowed, under (old) 135.181, to fly IFR for no more than 15 minutes to reach an area of VFR weather, or to shoot an approach in IFR if the pilot encountered unforecast IFR conditions.

This 15-minute rule was often stretched to its limits, particularly since the regulations demand that the flight always be in a position to make a descent under VFR if the engine fails, meaning it was legal to go IFR for 15 minutes, but youd be illegal because the engine might quit.

The GA industry fought for and has now received dispensation to fly single-engine airplanes for IFR passenger hauling. The 15-minute rule is no longer needed so it was eliminated when no one was watching. Poof! The new regulation doesnt say turbine-singles only in so many words. But, in fact, that appears to be its true meaning.

The Cinder Path
Even under the best of circumstances, the Part 135 approval process can be frustrating. Every facet of the operation must be approved by an ops inspector who bases all approvals on guidance received from an imponderable administrative labyrinth above, where power is absolute, responsibility is diffused and no ones in the office on Fridays after 3 p.m. To consider a single-engine aircraft for IFR 135, the supplicant needs to pay close attention to FAR Parts 135.105, 135.163, 135.181 and 13.421. All are open to interpretation. Well condense them to give the flavor. In order to provide on-demand service in SEIFR with passengers, the operator must have:

A pilot in command and a second in command or an approved three-axes autopilot. Easy enough.

The aircraft must have two independent electrical power-generating sources (alternator or generator and the accompanying regulators and such), each of which is able to supply all probable combinations of in-flight electrical loads for required instruments and equipment.

In other words, two good electrical systems on one engine. Or, you must have one electrical generating system plus a standby battery capable of supplying 150 percent of the loads for instruments and whatnot to get safely along in IFR for at least one hour in an emergency. Your basic mother-of-all-batteries.

you’ll need two independent sources (vacuum or electric) to run the gyroscopic instruments. In short, you’ll need dual electrical systems and dual vacuums on one engine. These capabilities are not widely available. Nor, as NATA (National Air Transportation Association) points out, will you find readily approved retrofit kits for 135-worthy piston singles. Bits and pieces of approvable systems, yes, but finding enough parts to complete the puzzle may be impossible. Brand-new singles such as the Cessna 206 or Piper Saratoga have dual vacuums but not dual electrical. Two examples of production piston singles capable of dual vacuum and dual electrical are the Piper Malibu and the Beech A36. The newer A36 has an electrically powered back-up vacuum and an emergency back-up generator.

The larger Continental engines stand a better chance of handling redundant systems. However, space under the cowl gets tight if the dual systems compete with air conditioning. Lycomings have limited space available on the accessory case-the actual spots where things like vacuum, fuel or hydraulic pumps might be bolted. To add one item, you’ll sacrifice another.

A back-up battery could be installed in some aircraft, but hard to get anyone, including the FAA, to say if retrofits would be Part 135 approved. Cessna reports no domestic customer demand for piston SEIFR, so they have no plan to support SEIFR 135 certification. New Piper has no new plans, either. Beechcraft can sell you a nice A36 or B36TC which would appear to meet the criteria, but hardware acquisition isn’t the only obstacle. Assuming you somehow cobble everything together and find an FAA inspector willing to stick his/her administrative neck out, then you must meet the fourth challenge-FAR 135.421 (c). You must have in your approved maintenance program a manufacturers recommended engine trend monitoring program, which, among other things not specified in 135.421(c), may require oil analysis.

Oil analysis is no big deal. Heck, for $10 a pop, you can find plenty of labs to burn a sample. Unfortunately, neither Lycoming nor Continental has a recommended engine trend monitoring program for recips. They do have recommendations for trend monitoring, such as time between oil changes and they do recommend oil analysis.

But that loose collection of normal maintenance and warranty procedures does not constitute a recommended engine trend monitoring program. It doesnt specifically say, for example, how much iron or aluminum can turn up in an oil sample and still represent an engine thats safe to fly. That sends you back to the local FAA FSDO office for a field approval for your own engine trend monitoring program.

Okay, so whats the problem? Your mechanic should be able to put together a reasonable program using oil analysis and on board monitors with all the data logged for inspection. A GEM 610 or JPI EDM-700 should fit the bill, right? This, in a reasonable world, should meet the spirit if not the letter of the reg.

But who says we live in a reasonable world? The chances of your local FSDO approving a not-already-approved engine trend monitoring program are, to say the least, remote for your piston engine.

Not that the local FSDO personnel are being dipsticks in the administrative mud. On the contrary, the FAA is required to tell you how to comply with a regulation and they would love to accommodate but they have no guidelines yet for making such approvals. All hands are tied, but its difficult to say who wrapped up this Gordian knot. Its as though Moses handed out the Commandments and said, …I havent had a chance to go over these yet; do the best you can.

The upshot is this: Forget getting SEIFR 135 passenger carrying approval in your piston single any time soon. It may come when the FAA figures it out themselves. Or when some lunatic takes hostages in a FSDO and threatens to shoot an inspector every hour unless his single-engine ATCO is produced forthwith. In the meantime, some operators have cracked the conundrum the old-fashioned way by spending millions of dollars to purchase turbine-powered singles, namely the Pilatus PC12 and the venerable Cessna 208 Caravan.

Turbines have a better chance of already having a manufacturers recommended engine trend monitoring program. System redundancy is more common, too. The Pilatus PC12, we were told by one operator, has no problem getting approval and required no modification. In the case of the Caravan, a modification for dual (or standby) vacuums can be made with little more than the usual paperwork travails.

Meanwhile, the piston single still has utility. It can haul cargo under Part 135, VFR or IFR. Passengers can still be carried under 135 VFR provided they arent too concerned if they have to scud run under the bases of the clouds in minimal visibility or over-the-top of a layer that has big enough holes to allow a VFR descent if that single engine fails. In other words, nothing has changed.

Perhaps this recent revision to Part 135 needs a little tweaking or maybe it was subtly designed to discourage SEIFR 135 piston/passenger-packing operations. Keeping abreast is NATA (National Air Transportation Association). They can be reached at 703-845-9000. Or perhaps your local FSDO has had a stroke of inspiration and figured out a way to approve piston singles for IFR. Hey, it never hurts to ask em. (Just don’t throw away your current Trade-A-Plane with all those good deals on used Caravans.)

Meanwhile, if you feel inclined to pursue SEIFR 135 passenger certification, may we suggest you begin by re-reading Catch 22. you’ll begin to appreciate the administrative task ahead. Good luck. And let us know if you get this to work out.

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by Paul Berge

Paul Berge is a CFI and freelance writer.