Slinging in the 412
Hi Guys,
Further to Tribals excellent advice, I would also warn you that most 412 HP/EP aircraft with DF engines have very twitchy FCU's - so once you do get above that steady 95% Mast Tq on lift, you are into the 'twitch range' and need to pull in your remaining 5% power very gently to avoid an overtorque (which does you no good whatsoever in this aircraft anyway - except result in nasty interviews with the Boss!). The co-pilot's overtorque light tends to be the first one to illiminate - usually as the P1's is oscillating gently about 98-99% - so even though your TQ Meter says you've got something left in hand, you haven't! Use the co to call the Torques as his will normally be the slightly higher reading of the two! Also if you have slightly different speed FCU's this in the range within which the engine torques might split - so you will have to trim your N2 lateral beeps (DF engined aircraft only) or even carefully tweak a throttle slightly to ensure the needles stay together through to 100%. Sometimes the naughty ones oscillate in this range also! What fun!
Tribal is spot on with the pedal input/torque demand problems too. If you have good vertical motion with the load (which you must aim to lift from the deck at or below about 85% Mast Tq to have the required power in hand for a safe transition with low wind/90% with a higher wind)) you will need to start your rotation (into wind, or preferably with the wind from Red 30 to Green 10) before you lose vertical motion, - in order to get the requisite nose-down for a safe transition. In normal pax operations, modern proposed JAR Perf E recommendations now point to using 95% to max available Mast TQ (carefully!) and then using a whole 15 to 20 degrees nose-down for the transition to Vy/VBROC (70KIAS, not 60 as some people insist on thinking!) within the 9 seconds of the 'Exposure Profile' ('Rotation' to 'Vy' time - not TDP or Vtoss off a helideck!). For Underslung Loads, - particularly long-lines from a deck (or land surface) your will only be able to put in a gentle nose-forward pitch at the rotation point of about 5 to 10/15 degrees. Unlike the 205/212/214B, the four-bladed messy 412 monster hasn't the inertia in the head to allow you to happily 'pull to the bells' and chuck in a huge nose down attitude on departure to 'pendulum' the load off the ground and then accelerate through Translational Lift speed using the 'sling-shot' effect of that 'pendulum-effect' departure. Ah! - Such halcyon days of Yore!
Le Slug 412 however, will fall out of the sky doing this - due to its 'LO (i.e. NO) -Inertia Head! Remember that the 412 likes to have at least 8 knots of wind to attain MTOW graph performance -especially with OATs above 25 degrees. Winds above that -no worries - except that the flight deck turbulence will require you to shuffle at very low skid height about the deck to get into wind before departure with pax/internal cargo. No 10-foot hovers in this beast at MAUW! Best not to turn off the wind at all for deck landings in wind speeds above 20 knots or in the Classic or older SP/HPs you won't have the torque on lift to turn back into wind as the tail rotor input will overtorque you quite quickly and alarmingly! Remember your TR charts in the PFM - the 412 hates winds from abaft the beam and likes to fall out of the sky at that point, leaving you pedaling like you're in a kids go-cart!
As the fixed USL mirrors are crap for long-line work - particularly to offshore platforms/decks, I would recommend that you take a suitably competent and well-briefed co-pilot in the LHS, then on the run-in for the deck with the load, <45 KIAS (and also during the initial take-off to position over the load) he loosens his lap-strap about 12 inches, which allows him to turn slightly in the seat, grip the leather door strap firmly with his right hand, while opening (and firmly gripping!) his lower door handle with his left hand - and between those two 'geometrically locked' hands he can firmly hold the door partially open and at the same time look out and talk you down with the load to the desired landing point giving the usual con 'patter' with reference to height and speed for the load (Word-Picture-Information as my old mate Robbo used to say!). He can also confirm proper subsequent release/unhooking of the load and or strop without any nasty lateral/fore/aft drift over the load. This is particularly effective for changing out flare heads on offshore platforms, where very accurate positioning is required for safe installation. Of course if you have a proper 'bubble' load door in the LHS with instrumentation included, then just fly the load from the LHS like a 212! What joy! Just remember that if you are flying a 412 Classic or an SP (or HP with BF engines) you won't have the same engine/torque response/pulling power for the same amount of lever movement that you would have had in a DF-engined aircraft, nor will you have the same level of power margin under any set circumstances. As the Older Classic and SP aircraft - in particular - age, the machine will not normally perform to graph expectations (especially in low wind conditions) and you will, by necessity, have to work at minimal fuel loads or with reduced MAUWs (usually by reducing the published weight by about 600 to 800 lbs depending on the ambient wind conditions). The older (212-type) torquemeter instruments are much steadier but have no overtorque warning lights and will - effectively - give you much less raw 'grunt' or 'pulling power' than the more reactive (and excitable) DF-equipped HP and EP split-type Mast Torquemeters.
Happy humping! Any more questions - fire away!