Sep 13th

SAFETY NOTICE: Plastic Fuel Flow Sensor Jet Installation

By Dave Schultz
MGL Avionics
SAFETY NOTICE: Plastic Fuel Flow Sensor Jet Installation
Safety Notice regarding the Installation of Restrictor Jets in the Plastic Fuel Flow Sensor


Fuel Flow
Plastic Fuel Flow Sensor

This is an important safety notice regarding the installation of restrictor jets in the plastic fuel flow sensor sold by MGL Avionics. The fuel flow sensor is pictured at Right.



  • If you have purchased/installed this sensor, please read on.
  • Please share this notice on your aircraft builder forum


These flow sensors are made by an outside company and are normally used with smaller aircraft engines such as Rotax, Jabiru and Hirth.


There is no safety issue with this sensor itself - but installing the incorrect restrictor jet can result in a safety of flight issue.


Each sensor is delivered with 4 restrictor jets in a small pastic bag. These jets are 1mm, 2mm, 3mm, 4mm diameter. While each jet can handle a wide range of flow rates, there is a corresponding pressure drop through each jet, which means that the actual flow rate possible is very dependant on fuel pump pressure. As outlined in the fuel flow sensor manual, it is very important to determine adequate fuel delivery after installation of the fuel flow sensor, and before attempting flight.


Inserting a jet into the flow sensor that is too small for your fuel system can and will result in the inability to deliver fuel to the engine. And, while the lack of fuel delivery is normally very apparent during a full power engine runup, there have been cases where flight has been attempted without adequately verifying fuel delivery.


Fuel Flow Jet open
Image showing the internals of the plastic fuel flow sensor and the restrictor jet



Please see this diagram as a guideline of which jet to use (typically the 2mm and 3mm jets are used):


Fuel Flow Sensor Jets 



Of course, the issue of ensuring good fuel delivery brings up the more general issue of the importance of creating a good Flight Test Plan, as outlined in the recommendations of the recent NTSB Safety of Amateur-Built Experimental Aircraft Study (found here). This study shows that a very high number of accidents happen in the first few hours of flight in a newly-built Experimental Aircraft. And many of these accidents are related to inadequate verification of powerplant and fuel delivery operation before flight is attempted. Also, many of these accidents take place in aircraft where the pilot has not been a part of the build project since the beginning. So, since fuel delivery is such a critical requirement for safe flight, we would like to emphasize the importance of a good Flight Test Plan, including full power runups and extensive ground testing before any flight is attempted.

Jun 30th

Rotax 912 Fuel Pump

By Dave Schultz
Brian Carpenter, of Rainbow Aviation, reviews the 912 fuel pump and how to remove and reinstall the unit.

Another great video brought to you by the EAA!

Jun 30th

Rotax 912 Spark Plug Removal/Reinstallation

By Dave Schultz

Brian Carpenter, of Rainbow Aviation, reviews how to remove and reinstall spark plugs on a Rotax 912 engine.

Another great video brought to you by the EAA!

Jun 29th

Why Oil Analysis? Learn what's going on in your engine!

By Dave Schultz

Why Oil Analysis?

Learn what's going on in your engine.


Oil analysis is a quick, nondestructive way to gauge the health of an engine by looking at what's in the oil. People use oil analysis for different reasons: to see if there are any problems developing, to see if their oil is working well in the engine, and to see if they can run longer oil changes.

What does a standard analysis include?

Spectral exam:

In the spectral exam, we take a portion of your oil sample and run it through a machine called a spectrometer. The spectrometer analyzes the oil and tells us the levels of the various metals and additives that are present in the oil. This gives us a gauge of how much your engine is wearing.

Insolubles test:

The insolubles test measures the amount of abrasive solids that are present in the oil. The solids are formed by oil oxidation (when the oil breaks down due to the presence of oxygen, accelerated by heat) and blow-by past the rings. This test tells you how good a job the oil filter is doing, and to what extent the oil has oxidized.

Viscosity test:

The viscosity measures the grade, or thickness, of the oil. Whether it's supposed to be a 5W/30, 15W/40, or some other grade, (within a range) what the viscosity should be. If your viscosity falls outside that range, there's probably a reason: the oil could have been overheated or contaminated with fuel, moisture, or coolant.

Flash Point test:

The Flash Point test measures the temperature at which vapors from the oil ignite. For any specific grade of oil, know what temperature the oil should flash at. If it flashes at or above that level, the oil is not contaminated. If the oil flashes off lower than it should, then it's probably been contaminated with something. Fuel is the most common contaminant in oil.

Blackstone tests engine oil from cars, trucks, boats, motorcycles, airplanes, and more. But we'll test other types of oil as well. The cost for a standard analysis is the same for oil out of any of the following systems:

  • Transmissions
  • Gear boxes (differentials, transfer cases, etc.)
  • Power steering reservoirs
  • Generators
  • Air compressors
  • ... and more!


Established in Fort Wayne, Indiana, in 1985, Blackstone Laboratories strives to provide an easy-to-use, understandable, and accurate oil analysis program with the fastest turnaround in the industry. At the heart of our program is ICP (inductive coupled plasma) spectrometry, database averages for comparing wear, and a comments section on each report that explains — in plain English! — what your results mean. The cost of analysis is $25.00.

Just fill out the kit request form for a free sampling kit on-line at:


Blackstone Laboratories

416 East Pettit Avenue

Telephone: 260-744-2380 (8-5 EST)

Fax: 260-745-2200

Fort Wayne, IN 46806

Jun 28th

Forgetting to remove the old oil filter gasket of an engine can cost $20,000

By Dave Schultz

Forgetting to remove the old oil filter gasket of an engine can cost $20,000, according to a safety tip received by Light Plane World.

An experienced Rotax 912 owner was distracted and failed to notice the old oil filter gasket was retained on the engine case when a new filter with gasket was installed.

It was a busy day at a small airport on Long Island, New York, when Igor Kolpakchi changed the oil and oil filter on his Rotax 912 engine as he had done many times before. After reassembly, the engine was started and checked for evidence of leaks and for proper oil pressure. Everything was fine, so after a normal engine warm-up, he made a takeoff from the airport where he has flown for many years.

The first indication of trouble came in a radio call immediately after liftoff advising that his engine was trailing smoke. The instruments didn't indicate a problem, and Igor assumed the smoke was from oil spilled on the exhaust. So he continued the takeoff. About 20 seconds into the flight the engine warning light came on, and the engine stopped completely a few seconds later.

Fortunately he was in his Aeroprakt A-20 Vista LSA that he has flown for many years including numerous deadstick landings, practicing and competing in microlight competitions. Igor has flown in two world championships and is the only U.S. Microlight Team member to compete in both trikes and fixed wings in the two-wing-place categories. He said the deadstick landing was routine and that he was able to execute a complete 360-degree turn and land back on the field into the wind. He credits the performance of the airplane and said he would not have made it back to the field in a typical Cessna.

Inspection revealed oil had blown out past the oil filter gasket but apparently only at full power setting. The gasket hadn't failed or ruptured, but the presence of an extra gasket allowed the blowout. The two front pistons had disintegrated and the cylinders were destroyed along with broken or bent connecting rods. The rear cylinders were intact because in the climbing attitude they still received some lubrication. Rotax engine mechanic Jim Leon at The Ultralight Place confirmed the estimate for repair is likely to be equal or more than the cost of a new 912 engine as extensive further damage is sure to be found. The type of oil filter involved in this incident wasn't identified, but Jim recommends using only the latest genuine Rotax oil filter.

Igor wants to remind Light Plane World readers to take care and realize that a very small oversight can cost a lot in dollars or worse if you don't make it back to the field. He was able to save the smoking airplane in front of a lot of witnesses, thereby enhancing his reputation for pilot skill, though at considerable cost.

Jun 20th

BluLink Pilot Headset Adapter

By Dave Schultz
BluLink enables you to use your Bluetooth cell phone and any music source wirelessly in the cockpit. You can use your existing general aviation, helicopter or BOSE® panel mount aviation headset with BluLink. No more tucking your cell phone under your headset or using cell phone adapters with various cords and additional adapters. The BluLink will work with any cell phone with Bluetooth.
Jun 8th

ATC Separation for Wake Turbulence

By Dave Schultz

ATC Separation for Wake Turbulence

Featuring John Krug - view profile

Subscriber Question:
"You are taxiing for takeoff at a busy multi-use airport. Reaching the runway you see that you are following a Boeing 737, and several planes are now behind you in the lineup. The tower is launching departures as fast as they can. You are worried about wake turbulence separation. How do you handle this situation?" - Colin B.

John Krug:
"Because of the possible effects of wake turbulence, ATC is required to provide certain separation minima between aircraft of different weight classes.

The separation used depends upon the aircraft involved and relative positions.

A 3-minute interval will be provided when a small aircraft (less than 12,500 pounds) will take off from an intersection on the same runway.

A two minute interval is provided when the previous departure is a heavy jet or B757 and the small aircraft is departing from the same threshold.

In the situation that you describe, a small aircraft following a large, ATC is only required to provide the small aircraft a cautionary advisory for wake turbulence.

You may request additional separation for wake turbulence if you feel that you need it. This request should be made as soon as practicable on the ground control frequency and at least before taxing on the runway.

The controller may juggle the departure sequence to minimize the delay. For example, if there are 2 or more light aircraft, they may be sequenced together to avoid excessive delays.

You may also request an early turn to avoid flying in the path of the departure. Make sure the turn is on the upwind side. Try to liftoff prior to the large aircraft to avoid wake turbulence."

Full article at:

May 31st

Rotax releases mandatory Alert Service Bulletin requiring immediate action on affected 912 series engines.

By Dave Schultz

Rotax releases mandatory Alert Service Bulletin requiring immediate action on affected 912 series engines.

Rotax has released Mandatory Alert Service Bulletin ASB-912-061 covering specific part number and serial number ranges of fuel pumps which were manufactured since late 2011 and supplied on new engines or as spare parts. The actual affected component is the pressure fuel hose assembly attached to these specific fuel pumps (see Alert Service Bulletin for list of specific engines, fuel pumps or fuel hoses affected).

Engines affected will require replacement of the fuel pressure hose as well as an inspection and cleaning of the pressure side of the fuel system including carburetors BEFORE NEXT FLIGHT.

Although parts replacements are not immediately available, they are expected to be procured shortly. For detailed information on engine serial numbers and fuel pump part number and serial numbers affected, please see the Alert Service Bulletin.

Rotax Owner has released a new video to help explain and clarify the information found in this Alert Service Bulletin ASB-912-061. Stay tuned for updates to this video and further information on parts availability and compliance instructions as they become available.

Best regards,
Dave Schultz
"Fly like your life depends on it"

May 16th

Manuals: Do YOU Really Need Them?

By Dave Schultz

Written by Rotax Owner

The prudent answer is YES and absolutely !

At the same time you pick up a screwdriver or wrench and get ready to perform some work on your trusty Rotax engine, be it a 2 or 4 stroke, you should also be reaching for your engine manual. Let’s face it a manual is as important as your wrench. Your neighbor is not a walking Wikipedia and won’t always provide the correct advice or at least perhaps not in correct sequence.

Even if you think you know, or remember what to do, something unexpected always comes up. What to torque a bolt or nut is a good example. You may need the Line Maintenance manual, the Heavy Maintenance manual or the Parts manual. Another good manual application would be to check if you are required to have a space between certain parts and if so how much space.

This list can go on forever. All smart mechanics and owners will know that the path to easier maintenance and successful engine ownership requires manuals for reference. Even if you are screwdriver challenged and never intend to touch your own engine reading up on the particulars of your engine will help your and the mechanic and you may be able to keep them on a correct path. If your mechanic doesn’t have your engine manuals then have him print them out or you can give him a set for his birthday.

You should source and have on hand all the manuals that apply to your engine. For example the Rotax 912 series engine has 5 manuals that apply to your everyday needs and will answer just about any question that may come up pertaining to that engine.

Many questions right here on the forum can have an answer ascertained from these manuals in a few minutes. I do agree that sometimes there could be a little more information provided or maybe just a little better explanation, but the manuals are an absolute must. The reason you need them all is because information may not be in the book you are using on a specific task. An example of this is the torque settings on many nuts or bolts for a special application. It may have a special torque value that is not the same as another nut or bolt found somewhere else on the engine of the same size. You can buy these manuals or you can print them out right here on the Rotax-Owners Forum.

Purchase a three ring binder and crank up your printer. While you’re at it make sure to print any Service Bulletins, Alerts or Service Information that pertains to your particular engine and keep them on hand as well. I use the manuals all the time in the shop. You just can’t remember everything, besides you need to know when your neighbor’s advice was wrong. These manuals are your Bible, encyclopedia and teacher. You need them to make life easier for yourself and your engine. Follow them and the inspection periods and maintenance schedules will stand a good chance of not having any major issues.

I do realize that engines are mechanical things and do fail so this is another reason the keep your manuals on hand. All engines need maintenance for proper functioning and neglected engines will usually cause the engine owner grief of some sort sooner or later.

Don’t wait for a problem to arise. Read through each manual or table of contents and get some idea of where things are, and read up on how to accomplish a simple procedure. The night before you are going to perform some specific task is a good time to flip open the manual and read up on the procedure.

I know this isn’t a technical article, but I get questions everyday about fairly simple things that are already in the appropriate engine manual. Don’t get me wrong I really don’t mind the calls and I enjoy talking to people from all over the world, but if I can get them to pull up the manual and then point them in the right direction chances are better they will get it right and the next time they will have it right at their fingertips be better equipped to deal with many issues right on the spot… all at home… with that trusty manual.


Service Bulletins:

Full article at:

Apr 16th

Installing a Ground Adjustable Propeller

By Dave Schultz
Brian Carpenter, of Rainbow Aviation, shows us how to properly install a ground adjustable propeller. The guidelines are for Sensenich, but apply to many different propeller manufacturers.

Another great video brought to you by the EAA!

Best regards,
Dave Schultz

Fly Like Your Life Depends On It!