CASA CAO 95.7 anomaly
Heliport is onto one aspect. I wonder also do many of the posts relate to informed opinion of what others do. If they are not informed, they are not interested, if they are not interested, there’s the door – strong but life saving jungle talk.
ICAO rules are a reflection of the political weight that formed them; on this subject, way out of pace it seems with reality in everybody’s backyard. ICAO therefore needs purging, to regulate in conformance with reality. Those that quote ICAO should give over, take the blinkers off. There are many instances where leaving your place of employment in a hurry for safety sake is a reality.
Shutting down unnecessarily in a hostile remote environmet is also stupid.
Often when mustering it was imperitive to be back in the air very quickly when refuelling or risk losing control of your task.
However to adopt the practice of seat departure in any air transport op, or say fire fighting ops where everything is laid on with equipment, manpower etc after many deliberations on SOP’s months before has obviously got to be questionable.
ICAO rules should reflect the imperatives of the different environments to protect their constituents.
There are a couple of pertinent points
1) as per Eacott's quote of the OZ CAO 95.7 (immediate vicinity) this does not mean as Shy quoted, about some dude retiring to the latte’ society for a recharge whilst Rotors are still in motion (RIM).
Neither does it mean walking around Fox Glacier to look at the view having just descended from the 1 million dollars worth of viewmaster machinery?? - Bloody hell. !! And on an RPT tourist flight into the bargain!!
2) Mr Bally has hit on another and I’ll put it to bed as well as him because I could be on a mission to tuck him in on another thread.
Bally you say,
“How is a gust of wind going to knock a helicopter over when the blades are flat against it (180degs)?”
I’ll not be disappointed if you answer in the negative when I ask did you ever get taught to lean the disk into wind a bit if there is a storm coming and to always park the machine off-line the incoming storm wind 15 degrees so as when blade sailing occurs during shutdown you don’t cut the tail off. The reason I’m not surprised if you say no, is because I know of an identical case recently in an R22 where that happened. The 3000 hour pilot was simply not told of the phenomena and didn’t have the scone to work it out.
But Bally what is it that we do all day, lift the collective and select the desired direction with the cyclic?
Well yes, but really we are varyibg the A of A on the blades. To first slip the surly bonds of earth we lift the collective for symmetrical lift.
When we move the cyclic in the desired direction we are altering the A of A of the blades in each half of the disc to create a dissymmetry of lift and thus create a thrust moment toward the desired direction? Operating the throttle during these sequences is to replace power used in the manoeuvres to maintain RPM as we compensate with more collective and or pedals.
Now let’s go to your bit about the ‘gust of wind with blades flat against it.’
Remember the references to landing in Wolf Crater, “the wind was blowing straight down”? Ever been in northern OZ during the build-ups when you can often look out the window and see the tree leaves all pointing straight down, or for that matter ever stood on an ocean jetty with a prevailing sea current and wondered why most of the time all the water is going the wrong way? No? I didn’t think so! Obviously at times when the wind is going straight down there are other times when it is going straight up, or any other which way!
A wind forecast is merely an ‘expression’ of the time that it is estimated that two differing atmospheric pressures may tend to equalise, expressed as a wind velocity and direction. Of course they never do and neither is any of the close to ground interferences ever accounted for in that forecast. As low level pilots we have to think of that and we encounter these ‘situations’ hundreds of f’n times every day, especially when we park our machine with RIM facing into a gusting wind that can and does vary continuously, thus changing the A of A on the blades continuously.
Bally, let’s take another small step. Let’s say you’re in a light helicopter; its flat pitch power requirement is say 13”. You take off at daylight, yourself and full fuel and gee whiz you only need another 8-9” to get off the ground. At the end of the day, temps are about the same, you’re in a hurry to close a gate behind the cattle, you’re just about out of fuel, that is, suddenly there is 400 pound less in the machine compared to take off with full tanks this morning, it’s sitting at flat pitch, blades level, you left the RPM inadvertently at operating RPM, collective is locked down and the bloody wind gusts upwards over the little rise in front of you and hey presto, the helicopter nose is climbing.
Note two things;
a) In a Bell 47 one inch equals 100 pound, straight up, and
b) It takes stuff all wind to turn a big powerful windmill.
Compensated power is not an issue, as the damage is done and RPM simply decays now as the machine lifts, unless of course you are in a Robinson with those idiot electric governors and you like an idiot left it switched on, then they just fly higher before crashing.
So, Bally at your expense I have finally isolated an anomaly in CAO 95.7, it refers to something that we have always done.
What should be included is a section to detail that the rotors should always be set well below operating RPM and therefore not capable of generating enough lift to lift the empty machine when the pilot is to get out. They should not just be - at flight idle - which might be interpreted as operating RPM with the throttle under the detent.
If that and a Governor-off requirement for the Robinsons are included in 95.7 it may help blokes like you as it should then have been included in a training sequence.
Thanks mate you’ve been a great help, oh, and in the future, think!