Safety Corner

DISCLAIMER: The personal experience and grief of other Moni owners have provided the safety advice you find here for your benefit and edification. This data has been collected since 1986 through the various Moni newsletters and the Moni user community. The main intent here is to make you aware of some of the potential problem areas in the Moni design and for you to make an informed decision for solving those problems. Ultimately, it is YOUR responsibility to decide how to use this information and whether your aircraft is safe or not to fly. Use this advice at your own discretion and if you have any safety tips to contribute please do so! Thank you.

Now that we've got that out of the way, here are some very useful safety tips. They are in no particular order of importance since they are all important. To those of you who have shared your experiences for the benefit of our group I wish to personally thank you for your caring and unselfishness.

Riveting the Wings | Canopy Latch Mechanism | KFM Engines with OVC Carb | Propellers/Propeller Bolts | Prop Strikes | Static RPM Prior to Takeoff | Spinner Failures | Fuel Filter Contamination | KFM Crankshaft Failures | Weight and Balance

Originally the Moni had bonded wings, meaning the aluminum wing skins were adhesively bonded to the wing structure. Several incidents and accidents prompted the designer to come out with an AD that calls for having the wings riveted. This is not optional! Your life depends on it! If your wings aren't riveted read this PIREP!

As originally designed, the canopy latch mechanism on the Moni is unreliable and many pilots have reported the canopy coming open in-flight. Please note that from pilot reports the aircraft remains controllable and will fly with the canopy open. ALWAYS remember to fly the aircraft first! Before you fly be sure to have an alternate means or a secondary safety catch for your canopy. It could save your whole day. Want more details? Read these PIREP's.

Many pilots flying the OVC carb have reported poor running and "unexplained" engine stoppages. The solution came by adding an electric fuel pump which should be run at all times (low pressure type). Apparently the pump installation in the Moni KFM installation is prone to vapor lock. Not flying with an additional backup fuel pump is asking for trouble. It might also be a good idea to have a backup on BMR installations, although it seems the BMR's pulse pump is not as prone to trouble. Want more details? Read these PIREP's.

There have been several pilot reports of props coming off in- flight as well as failures of the AN-5 bolts that hold the prop. It appears that the cause of the bolt failures is due to using the improper length bolt, i.e. too long. When the bolt gets torqued down the nut bottoms out and stresses the bolt. Prop hubs are NOT all created equal. Their thickness may vary from prop to prop so it is VERY IMPORTANT that you double check you particular prop, hub and thrust plate thickness and make sure that you've got enough "meat" left on the bolt for when you re- torque the prop. Remember to re-torque the prop after your first hour of use and check the bolts and torque regularly. Want more details? Read these PIREP's.

If you experience a prop strike don't assume that the extent of your damage is limited to replacing the prop. There is a very definite probability for crankshaft failure. KFM Advisory Circular 01.007.001 recommends having the crankshaft disassembled followed by a magnetic particle inspection (Magnaflux process). On the propeller subject, several pilots have reported loosing their tips on Prince P-tip props (they have a "drooped wingtip" at the ends of the prop). There does not appear to be any good explanation for this. Some props throw their tips, some don't.

If you experience a prop strike you will most certainly experience a broken crankshaft down the line, usually within 20 hours. This has been reported by many pilots. Best advice: don't make that prop stop abruptly.

It may seem obvious, but it has been done before. DO NOT attempt to takeoff unless you're developing adequate static rpm. The Moni isn't exactly overpowered and the KFM only starts to deliver its hp in the 5000-6000 rpm range. Static rpm values will vary depending upon your particular propeller installation, however, as a rule of thumb, you should be getting at least 5000 static rpm.

The original spun aluminum spinners as supplied with the 25HP KFM have a propensity to develop cracks which will ultimately cause the spinner to depart usually damaging the prop on the way (and hopefully nothing else). Best advice: at the first signs of cracking, remove spinner or it will fail. Want more details? Read these PIREP's.

The ON/OFF valve supplied with most kits has a built-in mesh filter. There is no way to replace or inspect this filter once installed. It is advisable to remove this mesh filter and install a standard type in-line fuel filter that can be periodically replaced. A "quicker" 90-degree fuel shut-off valve should replace the original valve. Want more details? Read these PIREP's.

This is a controversial subject but it's one that needs to be exposed. While there are some people flying Moni's that have never had a crankshaft failure there have been many others that have, myself included. We are talking failure of the crankshaft for no apparent reason (ie. prop strike). I don't know if there's an exact time interval but I had one fail after 150 hours of use. In every case I've heard except one, the crankshaft has failed diagonally across the front journal. Typically, the engine will keep running after the failure although at a lower rpm. You can also hear some faint "pinging" noise. If left running long enough the rod end bearing will self-destruct causing the engine to seize.

If you ever read or saw pictures of the Moni in the trade magazines you never saw any ballast in the engine compartment or mention of the need for ballast. The truth of the matter is that the KFM powered Moni is very tail heavy and it will need between 25-35 lb. of ballast in the nose, depending on pilot weight, to be within the proper C.G. range. I know many builders cringe at the thought of adding up to 10% of the empty weight in ballast and some have tried not doing it. That is not a very good idea. The airplane will be very difficult if not impossible to fly at this extreme aft C.G. Please, be sure of your weight and balance numbers before you fly! Be suspicious of your computations if you come up with less that 25 lb. required. If in doubt double check! Wanna see some ballast?

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