Originally Posted by
aa5bpilot
I'm a fixed wing pilot. First some data, then some questions for the helo pilots here...
METARs and PIREPs around the time of the crash show the marine layer bases were around 1500' and tops around 2500', with marginal visibility:
According to the USGS Topo maps I have of the area, the highway elevation along the 101 tops out around 1100' just to the east of Las Virgines Rd, with hills up to 2000' to the north and south. Approaching Las Virgines, the highway dips into a valley and is at about 760' elevation. Two private helipads in the area are charted at 850' and 888'. Further west, the highway rises back to around 900' before descending through the Conejo Grade towards Camarillo.
Tracks posted upthread show N72EX was following US-101, at an altitude around 1200'. This suggests they were flying in hazy conditions just below the cloud deck. While the conditions were certainly marginal, they appear to have done just fine following the 101, and had already passed the highest portion of the highway along their route. (The south/east-bound turn started west of Las Virgines)
Assuming the FR24 and FA data are to be believed, N72EX then turned to the south/east, and possibly started a climb before the crash. My questions:
1) Are inadvertent IMC procedures the same for helos as fixed wing - that is, doing a 180? I'd imagine there are more options including trying to slow, hover, or try to set down short of a cloud bank if one sees it looming, or is that not practical?
2) What is the maximum climb capability of the S-76? (i.e. how long to get on top of a 1000' foot cloud layer, if required)
Putting it differently:
3) Are there any circumstances where a helo pilot would choose to turn and climb like that, knowing it would put them into a cloud especially if they weren't already?
The weather as you drop down to the west of Calabasas can change dramatically. I was on the freeway heading west from the Valley shortly after the accident and the weather deteriorated quite badly as I passed Calabasas towards Las Virgenes Rd. The marine layer funnels up Malibu Canyon and can settle on the 101 from Calabasas all the way to the Conejo Grade and down into the Camarillo Plain.
Ladyface Mountain in Agoura (3 miles W of the crash site) is right alongside the South side of the 101 and rises to 2031 feet.
The 101 in that 13 mile stretch is not the place for scud running.
The 2 helipads - one is at the LACFD Fire Station on Las Virgenes Rd and the other is LACSD Lost Hill Station.
On that morning all Police and Sheriff's Department helicopters were grounded due to viz...