Originally Posted by
terryp
Hi All,
I am a PPL holder and have been flying for over 10 years so have had my fair share of turbulence in light aircraft and as a passenger on commercial flights.
I arrived back from San Francisco earlier today and have experienced what I can only describe as the scariest thing in my entire life. Flying British Airways 747-400 from SFO, we were about an hour into the flight and the cabin crew had just finished handing out the first food serving as we started to experience some mild turbulence. Enough to make a nervous flyer uncomfortable but nothing than concerned me and the seatbelt signs were left off.
After a few minutes of this the turbulence went from mild to violent with the 747 being thrown around like I could never imagined. This started to make me a little uncomfortable, even as an experienced pilot and passenger, the seatbelt signs remained off and the cabin crew were still going about their business.
All of a sudden the 747 was flung violently upwards then slammed downwards as is if someone had hold of it by the tail. The engines had a clear loss of power and the aircraft went into a nose down attitude and began to bank right, all while still violently shaking, passengers screaming and trays drinks flung around the cabin. To be honest, I wasnt sure we were going to recover.
The seatbelt signs went on as the flight crew tried to regain control of the aircraft and put power back onto the engines. While they managed to do this we remained flying in these conditions for a further 45 minutes or so, the longest of my life I might add, the intermitently violent spells of turbulence until we reached the Atlantic and leaving Canada behind.
I spent the remaining 6 hours of the flight terrified at every jolt and its left me feeling I never want to get in an aircraft ever again! Now while I hope that won't be the case it has definately unnerved me significantly and I'm questioning whether I would want to feel that way again.
Has anyone else ever experienced this?
Having flown SFO-LHR a number of times (albeit as pax on UA 777's) my guess is that an hour into the flight would put you around Reno (or just a bit further East given the tailwind you had). I suspect therefore that what you experienced was something that's not actually uncommon and is known as rotor. It's an effect associated with Mountain Lee Wave and you get a lot of wave effect to the East of the Sierra Nevadas which are lined up perpendicular to the winds blowing in off the Pacific.
I've experienced rotor first hand a number of times when flying out of Minden (just South of Reno). If you're not expecting it, it's very, very unpleasant. For a PPL I'd fully expect you to be uncomfortable about flying through it. As a glider pilot, I've actualy used it numerous times as a way of gaining height in order to benefit from the smooth rsing air above it associated with wave. Minden is one of the World's most renowned soaring sites precisely because of its location which makes it ideal for wave conditions.
Usually ATC will advise airliners when there's known wave in the area but, like the weather, it's not always completely predictible. So, combine the unexpected sudden onset of the situation with the possible lack of awareness/experience of the crew in dealing with the problem (amazing how many CPL's don't know about thermals, wave and rotor) and thinks may have become a tad frantic for a while!