I just saw an amazing breakdown on /r/nba by someone who's a pilot himself
https://old.reddit.com/r/nba/comments/ev0ji5/helicopter_sikorsky_crashes_north_of_los_angeles/-----------------------------------------------------------------------------------------------------------------------
(I know this is probably a repost (video/audio of ATC) but I wanted to give some explanation to the video after I shared it with my family members and they were confused on some of the terminology that ATC and the pilot are using in the video. I will break it down in intervals and add some insight into the pilots possible thought process.)
My background: Naval helicopter pilot that has flown in the southern California area for close to 6 years and roughly 1,500 hours of pilot time. I have flown the route that the helicopter was on during the mishap a few times and can speak to the dangers of a marine layer and the possible spatial disorientation it can cause from personal experience.
Some ATC definitions, LA airspace and common aviation parlance.IFR: Instrument flight rules- Operations in weather that does not allow the aviator to guarantee separation on a see and avoid principle. Requires an instrument rated pilot, a transponder for radar following and a two way radio to operate in. In general, if weather falls below 1000 feet of ceiling for cloud clearance (from the ground to the bottoms of the clouds) and/or less than 3 miles of visibility, IFR must be used..
VFR: Visual flight rules- Operations that allow for a see and avoid principle. Can vary for different types of airspaces around airports, but typically when weather has greater than 1000 feet of ceiling for cloud clearance and greater than 3 miles of visibility.
SVFR: Special VFR (for helicopters) - operating under visual specific weather minimums allow helicopters, because they are slower and easier to maneuver around weather, that says you can operate within an airports airspace as long as you can maintain clear of clouds and 1 mile of visibility. If you want to transit through an airports controlled airspace during weather below VFR minimums, you need to request SVFR.
- The LA airspace is one of the busiest in the country, if not the world. Outside of LAX's Class B (biggest airports), you have multiple other B, C (smaller, still pretty big), and D (smaller, still towered) airports within 50 miles that dot the landscape. Burbank airport (class C) and Van Nuys (class D) airport are northwest of downtown and have specific helicopter routes that allow you to transition through the airspaces, most navigating along highways at prescribed altitudes that allow helicopters to operate within controlled airspace (usually 4000 feet and below within 10 miles of airports) without disrupting other fixed wing traffic.
- The communications you hear in the video are between the helicopter (callsign: 2EX, Two- Echo-Xray) and the control towers of those two airspaces. 2EX is attempting to transit from the southeast to the northwest through these airspaces.
The video:0:30 - 0:35 - (1021 AM Local time) 2EX has called Burbank Tower (not heard) and Burbank Tower responds with the information about the field. He tells 2EX that the field is IFR, the altimeter setting (barometric pressure that pilot sets to reference altitude on a barometric altimeter) and asks for his intentions (how he plans to proceed as he is not currently under an instrument clearance to proceed to the airport).
0:36-0:42 - (1021 AM Local time) 2EX responds that he wants to proceed westbound to pick up the 101 Freeway and proceed SVFR through the airports airspace. The pilot needs to ask for permission to do this because it means he intends to operate VFR even though the field is IFR.
0:42-0:50 - (1021 AM Local time) Burbank Tower tells 2EX to hold outside the airspace because he has an inbound aircraft that needs to go around on an approach and he needs to maintain separation for that aircraft so it can safely waveoff their approach and set up for another approach. It is unclear why this other aircraft is waving off but can somewhat be safely assumed the weather is a factor. 2EX agrees to hold outside the tower's airspace, which you can see he does with the small graphic doing circles on the screen as the video fast forwards for around 10 minutes.
0:50 (1021 AM Local time) The screen flashes the METAR (Meteorological Terminal Aviation Routine Weather Report), essentially, the current weather in coded format. Of note- it says the visibility is 2 1/2 miles, HZ (Haze), and ceilings are 1100 overcast (which is above 95% sky coverage, so pretty much complete). It does not say how thick that cloud layer is.
0:50-1:30 (1021-1032 AM Local time) Burbank town tells 2EX that they will need to continue holding as the aircraft that they have another aircraft on approach and the aircraft that just waved off needing to sequence in before they can clear 2EX through the airspace. 2EX acknowledges to continue holding and is then given instructions on what they can expect after those aircraft are clear.
1:30-2:05 (1032 -1033 AM Local time) Burbank tower makes a call to another aircraft to help out 2EX to get going as they have been holding for awhile now. He clears 2EX north along the 5 HWY (runs southeast to northwest) through the airspace using SVFR and at or below 2500 feet MSL (altitude in mean sea level). 2EX acknowledges and proceeds through the airspace.
- A quick aside. At this point, it is unclear how bad the weather is or if 2EX is actually maintaining SVFR rules or if the haze is making the visibility less that SVFR minimums. From my personal experience navigating in the marine layer a good amount over the past 6 years, it has varying levels of severity.
2:05-2:45 (1032-1037 AM Local time) Burbank tower gives 2EX the option of proceeding along the 118 Freeway and then rejoining the 5 as it heads toward Van Nuys airport's airspace. 2EX follows that route and checks in with Van Nuys Tower, telling the controller he is operating under SVFR and is at 1400' feet MSL.
2:45-3:21 (1037 AM Local time) Burbank tower clears 2EX through Van Nuys airspace and gives a similar weather report to Burbank tower. She also advises them to transit below 2500 feet MSL and to advise when they are VFR or when clear of the Van Nuys airspace to the west. 2EX acknowledges the instructions.
3:22-3:52 (1037-1039 AM Local time) Van Nuys Tower asks if they would like to contact So Cal (Souther California) approach when they are clear of the airspace to which 2EX responds in the affirmative. 2EX then asks if they can turn west toward the 101 as they are clear of the Van Nuys class D airspace to which she responds affirmative and asks if they are in VFR conditions to which 2EX says yes they are at 1500 feet MSL. Van Nuys Tower checks off with 2EX saying they can check in with So Cal Approach for flight following (a form of continued radar services while maintaining VFR provided because the approach controllers have radar coverage in the area)
3:52-4:24 (1039-1043 AM Local time) The video speeds up as the display indicates 2EX is turning south. At this point the only voice communication heard is So Cal approach asking 2EX if they are looking for flight following and to say their intentions as it seems they are veering off of 101 as previously intended. When the radar contact disappears, the last call was that 2EX was too low for flight following.
Some final thoughts:1. I do not do any of this analysis to pass judgement on the pilot heard in the video. It is rare that helicopter aviation is in the spot light like this and I just wanted to provide some context for what was happening. I have the deepest sympathies for the pilot, the passengers in the mishap and their loved ones.
2. Vertigo is a term you may hear that the pilot had during this mishap. Think of vertigo as being instantly drunk and unable to have your brain communicate function to your body. It can occur when you encounter clouds when you are not expecting it or believe that the horizon that you are referencing while flying is there when in reality it is not. I can see how that is confusing and there are many youtube videos that can show the effects of veritgo on pilots.
3. I have had incapacitating vertigo once while flying my helicopter and it was the scariest moment of my life. It was like nothing I have experienced before while flying and hope to never experience again. My motor functions and brain connection basically became disconnected and I was unable to tell if the aircraft was climbing / descending / turning / straight. It was at night and I went into the clouds at an area I was extremely familiar with. I was complacent to the mission I was conducting because I had done it so often and it nearly cost me my own life and the lives of 4 other people that night. I was saved by my copilot and his ability to use his training to get us back straight and level and talk me back onto the instrumentation.
4. I do not know if this pilot had vertigo or simply lost control of the aircraft. The bad weather, his intention to turn to the west and sudden departure to out of control flight (a climb to above 2000+ feet MSL and ultimately crash landing at 4000 feet per minute rate of descent) are indicators that some kind of spatial disorientation may have been a factor.
Long post, hope it was helpful if you were looking for some analysis on the recording.