A109E Fuzz Burners - engine Vs gearbox

[GipsyMagpie]

Noticed an odd discrepancy in the RFM. You cannot (are not allowed to) operate the Fuzz Burner for an engine chip on the ground but there isn't a similar restriction for the gearbox chip detectors (MGB, TGB, 90 Deg)

Anyone got any idea why?

[noooby]

Because Leonardo don't make the engines so they don't make the rules for them.

[PolarisPilot]

Not sure why the discrepancy. Could be a certification issue - the Gearboxes are made by Agusta, but the Engines are P/W.

There are a few other discrepancies in the Agusta RFM in any case. One example is the engine start procedure (I'm flying the S, not the E) . The procedure ends by stating "ENG 1 MODE switch : Set to Flight". However, during the Flight training, the instructor explained that if you do this, then the EDU page goes from Start to Cruise, and the TOT limits (for start) can't be monitored easily due to change of scale. I'm not sure if the Engine HOT START monitoring would be active if the MODE switch is to Flight. Hence we were all asked to start the second engine also with the first one in idle. Its likely that the person who wrote the RFM didn't think about this issue, believing that once the parameters were stable, you could put the switch to Flight and be done - but what about the second engine? There are also a few other discrepancies. The N2/Nr is supposed to indicate 100 in the RFM, but actually shows 101. A check with the maint manual showed me that its supposed to be 101.

We were told that the "E" RFM doesn't allow you to put off fuel pumps in case of a double generator failure, but the S manual does.

Not too sure... but these could be likely reasons. May be a good idea to write to Agusta (sorry, Leonardo) helicopters as well.

[Non-PC Plod]

The obvious answer would seem to be: because on the ground you can shut down and get maintenance to look at it, which might be safer than just burning the chip and getting airborne?

[ShyTorque]

We were told that the "E" RFM doesn't allow you to put off fuel pumps in case of a double generator failure, but the S manual does.

The 'S' drill actions require you to switch off the fuel pumps, rather than allowing it to be done; obviously it's to load shed the battery a little better following a double genny failure, to get the advertised 49 minutes of battery capacity. Maybe the engine suction pumps are more efficient/reliable on the S so the chances of a flameout are reduced? Don't know the answer to that - they're probably the same pump!

[helopat]

Engines don't have fuzz burners on the 109E...the only restriction on burning transmission chips is that you shouldn't burn chips if there are indications that the oil level is low (presumably so that you don't add a spark to a transmission full of oil vapour).

[Non-PC Plod]

There are 2 part numbers for chip burners on the 109E (appendix 4). One does just the main transmission and TGB, and one does the engines too.

[GipsyMagpie]

The obvious answer would seem to be: because on the ground you can shut down and get maintenance to look at it, which might be safer than just burning the chip and getting airborne?

Agreed but surely there would be the same logic for Eng and gearboxes.

Interesting point about the S. I'll look into that

[Non-PC Plod]

The requirement with a gearbox chip (which burns off) is to record it, and make sure you are not getting more than 2 per 50 flt hours.
With an engine chip, there is mandatory maintenence action before next flight. So, its logical you dont burn the engine chip on the ground, as you cant take off anyway.
So, an engine chip is more of an issue than a transmission chip - I guess the gearbox is more resilient to the occasional particle than the engine is.