No AWOS at N94. At the time of the accident, KCXY (15 mi east of N94 and home base of the accident B407), was reporting wind 270/5. Same for the hour before and after the accident.
I read west / northwest @ 10 during the time of the accident.
You'll find the wake vortex from forward flight and the downwash (rotorwash) from a hover are different aerodynamic results. The former happens after transitional lift and flows off the blade tips similar to wake vortex off an airplane's wings. It changes to rotor downwash when transitional lift is lost and flows out in all directions below the rotor disk and will be affected by the surface texture. See below. While the forward flight vortex can be altered by the wind, the hover downwash will not move in the same manner. So in this case, given the recommended separation distance/time for helicopter wake turbulence is 2 miles and 2 minutes, if the 150 approach to the runway was in less than a minute behind the 407, they ran into the existing wake vortex once they hit 15 feet and well before the static downwash from the hover position. There are a number of documents on this if you choose to look into further.
Yeah, that's not going to go over very well. They might as well get the checkbook out at this point
I don't know the position of the two aircraft, but... It's not per the AIM, it's per the Regs.
Clearly this post is a fraudulent attack on the two troopers. Their names have been revealed and any person can look it up on the Faa airman page.
Certainly most of us have "been there and done that" and maybe even wondered how we landed without incident when the sun was at the end of the runway flaring our bug-splattered windshield into oblivion.
Below is a pic being used in a different discussion to illustrate how the blade tip wake vortex stops as the helicopter transitions into a hover and the blade outflow becomes downwash with a more condensed, smaller circular footprint vs the long trailing wake vortex shown on the water.
Excellent visual.... please explain if I'm wrong.
Actually it’s a nearly verbatim critique by a certain YouTube aviation influencer that posts weekly Sunday-night videos with the central claim for this accident that straight-in approaches are bad. Therefore, PSP at fault. After watching the video last night, I came away unimpressed and unconvinced. This was not the Watsonville mid-air.
In my reply I was only addressing the false credentials posted about the two troopers and their false CTAF comment from “witnesses”. The approach, pattern, hover,150 pattern and flight and should he have gone around, I’ll wait for the report to come out and not speculate.
I'll take things that didn't happen for $100..Alex
Apologies for being imprecise with my words. When I said “If you’re going to argue…”, I didn’t mean you. I meant the aviation influencer associated with the post #85 line of attack.
The hovering diagram just depicts the initial rotor wash. While the make up of the rotor wash will differ between hovering and forward flight, surface wind will still move the rotor wash laterally across the ground.
www.airportmanagement.co.nz
No vendetta; facts are important. If Trooper Mills of Pennsylvania now has a commercial rotorcraft-helicopter rating, why isn't the FAA AIRMEN CERTIFICATION INQUIRY aware of it?
The easy answer to that is that the helicopter was not on the runway for 3 minutes after its arrival, which is supported by ADS-B data.
Slow or fast not the issue, but a consensus is as the 150 turned on final he interacted with the 407 blade tip vortex which caused the unusual attitude and flight noted by the IIC and the aircraft was already unstable or LOC prior to entering the video frame and well before near any hover downwash.
Except you can’t overlay the picture example to the 407 as the pic aircraft is more than twice the size and weight of a 407. The pic was to show how the blade tip vortex remains in the area and affecting the water surface well after the 212 moved on and was in the processes of converting to a hover where the vortex stopped.
I think that would be dependent of the surface make up. If the 407 was hovering over concrete vs the 6 inch grass there may be some movement but still not at the volume or speed to suck in the 150. And as noted in other discussions if it was hover downwash that upset the 150 it would have lifted the right wing up vs roll it right which a blade tip vortex would do.
If facts are important, perhaps determine if the State Troopers operated under Public Use, Part 91, or Part 135 before asking your questions?
Sorry, you are totally correct on that one. So the I guess then the question is what changes in training, if any, will come out of this? And is it really an issue with training or the people involved in this incident?
Well sure, the grass will reduce outflow vs a hard surface but with 10 kts of wind, it’ll still get blown to the runway. It’s not going to stay stagnant around the helicopter. It’s not going to disturb the grass outside the disk either because it’s going to rise. No different than a dust cloud. Also, even while the aircraft is IGE stationary hover, its still producing tip vortices and the tail rotor thrust is being ejected toward the runway. All of that combined with 10 kt surface wind pushing it.
Yep. A slow Cessna is an uncontrollable Cessna. I have a propeller in the corner of my office as a testament to that.
I think the only thing being a bit exaggerated here is the volume and force of the downwash (rotorwash) of a Bell 407 in a stabilized 4 foot hover over a grass infield and 35-50 feet from the runway. And having spent many hours working in that specific rotorwash and others, I think I'll stick to my SWAG. Regardless, time will tell.
Sure they have as the process works exactly as it was designed to: find a probable cause. And not assign blame as others may think it should.
Interesting choice of words. Have any examples of such confluences?
podcasts.apple.com
podcasts.apple.com