BA911 G-APFE Mt. Fuji crash

[GAXLN]

It is 50 years ago today that BOAC lost Boeing 707-436 G-APFE which broke up over Mt. Fuji with the loss of all on board. As a young boy, I recall reading about the accident in the papers at the time. The aircraft had just taken off from Tokyo Haneda bound for Hong Kong with 113 passengers and 11 crew. A day previously a CP Air DC-8 had crashed on landing at Haneda with the loss of 64 passengers and crew. I was near Mt. Fuji last month and paused to remember those lost that on that sad day half a century ago. Mountain wave turbulence was identified as the cause with the airframe breaking up in mid air. Fortunately, air travel safety has improved by a significant factor since those days. Something we should all be grateful for as we remember the passengers, crew and their families and friends affected by this accident.

[The SSK]

I recall seeing a photo of G-APFE taxiing out at Tokyo past the remains of the CP DC8, it is one of the most poignant aviation images. I can't help but think what was in the minds of the 707's passengers as they looked out and saw the debris.

[ExSp33db1rd]

I was one of the two F/O's waiting at Kai Tak to take over, when we got to the airport we were told that it was "overdue"at the reporting point ( "waypoints" hadn't been invented ) VOR on the South coast of Japan. (name ? Kagoshima ?)

Both the F/O's killed were colleagues of mine, we started with BOAC on parallel intakes. One was a family friend and neighbour at home.

There were two Capt Dobsons on the then Hong Kong crew posting. The Company rang the wrong one.

It was common practice for crews flying that service to file VFR to the south of Japan then re-file IFR to HKG, and deliberately fly over Fuji to give the passengers a view of the mountain whilst still climbing out of Tokyo, dropping a wing to see down the crater. "no-one" admitted it" but everyone" - well, maybe not everyone - did it. ( or so I was told after the event )

That practice stopped, as did the practice of filing VFR flight plans, after that accident.

There was also some story of 2 Japanese Air Force high performance jet fighters getting into trouble at the same time, the turbulence on the lee side of the mountain put them into trouble with massive "G" forces being experienced.

It seems that the 707 broke up in midair, the crew drowning in fuel.

There was also a discrepancy in the number of male "body parts" and female "body parts" in comparison to the number of males and females recorded on the load sheet for weight and balance calculations. It later transpired that a troupe of Transvestites had been travelling on that flight.

Truth is Stranger than Fiction.

Don't pick me up on petty detail, it is 50 years ago and I'm sure it is all written down somewhere.

[Haraka]

Some cine film taken from the ground was made public . IIRC showing the main structure spiralling down, minus most of one wing. As stated above, the aircraft had apparently been flown over Mt. Fuji to give the passengers a good view.

[Cows getting bigger]

There's a short sequence at the attached from 17:40 onwards

https://www.youtube.com/watch?v=7KaVe624V3U

[Discorde]

There's a photo of 'FE in happier times in this article celebrating the 50th anniversary of the B707:

The 707 is fifty (http://steemrok.com/70750thv4)

[eckhard]

And here is a sad picture of her last moments.......

http://i1121.photobucket.com/albums/l507/harold_flyer/image.jpeg (http://s1121.photobucket.com/user/harold_flyer/media/image.jpeg.html)

[Shaggy Sheep Driver]

What was the cause of the DC8 crash?

[seafire6b]

What was the cause of the DC8 crash?

https://en.wikipedia.org/wiki/Canadian_Pacific_Air_Lines_Flight_402

ASN Aircraft accident Douglas DC-8-43 CF-CPK Tokyo-Haneda Airport (HND) (http://aviation-safety.net/database/record.php?id=19660304-0)

Because of poor weather conditions, the aircraft was about to divert to Taipei when advised that visibility at HND had improved, above minimums.


In turn that reminds me of the Vanguard accident at LHR six months earlier. After two discontinued approaches in fog, the flight was actually in the process diverting to MAN, when the Captain heard that another BEA Vanguard had landed at LHR.
Hence G-APEE's third and fateful attempt.

[Shaggy Sheep Driver]

Thanks for that.

[ZeBedie]

Drowning in fuel whilst still airborne - now that's a risk I didn't foresee. Not a nice way to go.

[Georgeablelovehowindia]

Google: 'Better On A Camel' then scroll down to 'Japan-The Mount Fuji Disaster, by James Wilson (1966).'

[aterpster]

It is 50 years ago today that BOAC lost Boeing 707-436 G-APFE which broke up over Mt. Fuji with the loss of all on board. As a young boy, I recall reading about the accident in the papers at the time. The aircraft had just taken off from Tokyo Haneda bound for Hong Kong with 113 passengers and 11 crew. A day previously a CP Air DC-8 had crashed on landing at Haneda with the loss of 64 passengers and crew. I was near Mt. Fuji last month and paused to remember those lost that on that sad day half a century ago. Mountain wave turbulence was identified as the cause with the airframe breaking up in mid air. Fortunately, air travel safety has improved by a significant factor since those days. Something we should all be grateful for as we remember the passengers, crew and their families and friends affected by this accident.

Re: the 707 breakup. Given the same circumstances you don't think today's airliners wouldn't break up?

[Shaggy Sheep Driver]

Drowning in fuel whilst still airborne - now that's a risk I didn't foresee. Not a nice way to go.

How could that happen?

[D120A]

SSD,

ISTR the aircraft suffered a vertical gust which induced a 'g' load far in excess of the design load for the wing. Hence the outer wing failure, and also the departure of all 4 engines from their pylons - they carried on under power from the fuel they carried and were found some distance ahead of the main wreckage.

The vertical (strictly, 'normal') gust load induced a corresponding design-exceeding deceleration due to the associated induced drag, and this was enough for the fuel in the centre section tank to slosh forward, break the front of the tank, and carry on until it reached the forward pressure bulkhead, just ahead of the flight deck. Thus the flight deck filled with fuel. The wing fuel behaved similarly, which explains the 'white mist' emanating from the whole span in the published pictures.

One hopes the sudden loads and accelerations experienced by all on board were enough to ensure that no one was conscious and aware of any of these elements of the mid-air break-up. Even 50 years on, these are sad to report.

R.I.P.

[Shaggy Sheep Driver]

Thanks D120A, for your clear explanation. Very sad event indeed.

[suninmyeyes]

All BOAC 707 pilots who retired were given a photo of that particular aircraft in flight with other pilots signatures underneath it. Not the happiest photo for a retirement present! BOAC got another aircraft to replace FE registration G-AWHU known to pilots as "The Saturn". It was very different to the other 707s and the other 707 pilots were not allowed to fly it, one of the differences was the switches went up for on and down for off unlike the other 707s or vice versa. So they just trained 9 crews to fly it and they flew nothing else for a while until it was converted.

[GAXLN]

Re: the 707 breakup. Given the same circumstances you don't think today's airliners wouldn't break up?

No, but I believe pilots are more alert to the risks so that has helped contribute to a reduction in risk and therefore an increase in safety. If you compare the accident statistics from the 1960's with those of today, given the increase in air movements, the increase in overall safety has been huge. I was at a conference last year where someone claimed that if the accident rates of the early 1960's applied today there would be a major crash somewhere in the world virtually every other day. Makes you think doesn't it?

In my original posting, I omitted to mention that I understand that Capt. Dobson was a Lancaster pilot with 617 squadron having joined them after the famous Dambusters raid.

ExSp33db1rd and others - thanks for the interesting comments and background you have provided.

[aterpster]

I was at a conference last year where someone claimed that if the accident rates of the early 1960's applied today there would be a major crash somewhere in the world virtually every other day. Makes you think doesn't it?

Not on point. What has transpired in the past 50 years to prevent a "Mt. Fuji tour?"

I was mistaken, though, that you were attributing this horrible accident to the design of an airplane I loved flying; the 707.

[aterpster]

All BOAC 707 pilots who retired were given a photo of that particular aircraft in flight with other pilots signatures underneath it. Not the happiest photo for a retirement present! BOAC got another aircraft to replace FE registration G-AWHU known to pilots as "The Saturn". It was very different to the other 707s and the other 707 pilots were not allowed to fly it, one of the differences was the switches went up for on and down for off unlike the other 707s or vice versa. So they just trained 9 crews to fly it and they flew nothing else for a while until it was converted.

Perhaps that was a TWA 707-300 diverted to BOAC. TWA "customized" their orders to have the switches go the wrong way. This came to an end with the L1011 and 767, which had push switches.

[aterpster]

And here is a sad picture of her last moments.......

http://i1121.photobucket.com/albums/l507/harold_flyer/image.jpeg (http://s1121.photobucket.com/user/harold_flyer/media/image.jpeg.html)

I recall that photo at the time. I was a new 707 F/O at the time. It made me very sad then, and does now.

The difference the comes with age: 50 years ago I thought, "How awful, but that won't happen to me."

[ExSp33db1rd]

Perhaps that was a TWA 707-300 diverted to BOAC. TWA "customized" their orders to have the switches go the wrong way. This came to an end with the L1011 and 767, which had push switches.


I see that I flew G-AWHU in 1970, but can't remember a switch position issue?

I do recall that BOAC bought 3 "second-hand" 707's originally owned by a USA company, forget which, but pretty sure it wasn't TWA, to operate the Tokyo - Moscow route. These were707 -336's as opposed to the majority of the 707 fleet, which were the original 707-436's, and had a longer range, Tokyo - Moscow being about the longest sector operated at that time, we also had a stash of high density fuel available for uplift at Tokyo, to make the route possible.

I don't know about 9 crews, but -336 crews were separate from the -436 crews, pilots didn't mix and match between the two fleets.

These first three -336's, being originally of USA origin, certainly had switches that operated in the opposite direction, just as American household light switches operate in the opposite way to British light switches, the Brits knock a switch down on entering a room, the Yanks knock it up.

BOAC decided that it was dangerous to leave these 3 a/c different to the rest of the 707 fleet, so changed them around - at enormous cost I believe.

In another era, years later, I was involved with a company who put an originally American 747 freighter on to the British register. The C.A.A. insisted that we re-write all the Flight Manuals, changing the word "light" for "lamp", ( or v.v. ? ) as they had been first written for the U.S. F.A.A.

I'm sure if a pilot hears a loud warning bell, and sees a bright red warning "light" in an engine fire handle, he doesn't care if it is called a "light" or a "lamp" - he still sh**s himself !

[Shaggy Sheep Driver]

Didn't the same 'upside down switch' scenario apply to at least one 1-11 on the BEA fleet? It (or they) were different to the rest having been acquired when another airline was merged with BEA?

[Planemike]

BOAC got another aircraft to replace FE registration G-AWHU known to pilots as "The Saturn". It was very different to the other 707s and the other 707 pilots were not allowed to fly it, one of the differences was the switches went up for on and down for off unlike the other 707s or vice versa. So they just trained 9 crews to fly it and they flew nothing else for a while until it was converted.


Jackson's BCA Vol 1 states G-AWHU 707-379C was purchased as a replacement for G-ARWE, this was burned out at Heathrow 08 Apr 68. This model appears to have been a "one off" on the UK Register.


The 707-336C fleet comprising nine aircraft that was acquired between 1966 (G-ASZF) and 1971 (G-AYLT)....

[Groundloop]

And the initial -336C fleet were operated as pure freighters with BOAC CARGO titles for quite a few years after delivery.

[Alan Baker]

To clarify the BOAC 707 situation, the first two P & W JT3D powered 707-336Cs (G-ASZF/G) were ordered in October 1964 as cargo aircraft on the basis that no British equivalent existed and were consequently imported duty free. The third example (G-ATWV) was ordered in July 1966 as a cargo aircraft but was delivered in November 1967 in passenger configuration due to a capacity shortage. This aircraft was also duty free which caused Caledonian and British Eagle to protest as they had had to pay import duty on their 707s. BOAC ordered a further 4 -336Cs, the last as late as October 1970. Although some were used as cargo aircraft, all of the BOAC -320Cs were convertible. In 1969 two 707-336Bs were ordered for the new trans-polar and trans-Siberian routes to Tokyo. These, of course, were pure passenger aircraft. The two 707-320Cs that BOAC acquired "second hand" were G-ATZD, a -365C delivered to British Eagle in 1967 and acquired after Eagle's bankruptcy in 1968 and G-AWHU, a -379C originally ordered by US supplemental Saturn Airways but sold to BOAC before delivery and thus not really second hand as it was delivered to BOAC direct from Seattle.

[Spooky 2]

It's true that the TWA aircraft of that vintage had the overhead switches reversed as they treated the overhead panel as a vertical panel much as one would view the FE panel. There was former VP Flight Ops who, I forget his name now, that was responsible for this. Maybe Apster recalls that individual as he was around for quite a while.


This design crept over to the Lufthansa fleets of that era as well since TWA was providing some technical assistance back in those early days. Clearly recall flying a former Lufthansa 727-100 with that design. Don't see any killer issues as this was limited to things like the landing light and seat belt signs as I recall.

[suninmyeyes]

I wonder when Boeing changed their philosopy on landing light switch position? I am sure on the original 747s I used to switch them up for on whereas on all modern Boeings it is down for on.


Going back to the BOAC 707. Thanks for correcting me Planemike, you are absolutely right, G-AWHU was the replacement for WE not FE. It was last registered as 4L-GAS and was delivered to a company in 2009 called Mach Avia who flew it for a while. Not bad as it was over 40 years old even then. It was flying until a few years ago and is presently stored in the United Arab Emirates at Fujairah.

[aterpster]

I

These first three -336's, being originally of USA origin, certainly had switches that operated in the opposite direction, just as American household light switches operate in the opposite way to British light switches, the Brits knock a switch down on entering a room, the Yanks knock it up.


TWA's 300 series were -331, -331B, and -331BA.

[Planemike]

Thanks for correcting me Planemike, you are absolutely right, G-AWHU was the replacement for WE not FE. It was last registered as 4L-GAS and was delivered to a company in 2009 called Mach Avia who flew it for a while. Not bad as it was over 40 years old even then. It was flying until a few years ago and is presently stored in the United Arab Emirates at Fujairah.


Registered 15 times with 13 different registrations. Some sort of record?

[Spooky 2]

Noticed the current Lufthansa 380 still uses this switch logic on the lights at least.

[aterpster]

It's true that the TWA aircraft of that vintage had the overhead switches reversed as they treated the overhead panel as a vertical panel much as one would view the FE panel. There was former VP Flight Ops who, I forget his name now, that was responsible for this. Maybe Apster recalls that individual as he was around for quite a while.

.

Gordon Granger

[India Four Two]

I remember this accident very clearly and in particular, reading about an 8mm movie camera that was recovered and used to estimate the vertical loads. After some searching, I found this Flight article which must be where I read about the camera:

https://www.flightglobal.com/FlightPDFArchive/1967/1967%20-%201067.PDF

The film sequences showed pictures of Tokyo Airport, the Tanzawa mountains and Lake Yamanaka, followed by two empty frames, then by pictures of what appeared to be passenger seats and / or carpet before suddenly coming to an end. Tests showed that a peak load of 7.5g was required to make the film-feeding malfunction so as to skip frames in this way.

The article also mentions fuel moving foreward but doesn't refer to the horrific consequences for the crew.

Here's the link to the article referred to in an earlier post:
Japan - The Mount Fuji Disaster, by James Wilson (1966) (http://betteronacamel.com/Japan-The-Mount-Fuji-Disaster-by-James-Wilson-1966-)

It's a very moving account by BOAC's Tokyo station manager.

[blind pew]

My first three aircraft were Trident, VC 10 and DC 9.

The Trident switches were opposite to the VC 10 and the DC 9 had the windshield as datem....above one way, below the opposite.

The Iron duck had a four engine flame out...engineer with Delhi belly had an urgent call of nature - if you can call a curry natural - during climb - did the leaving the panel checklist which was switch all of the fuel pumps on (he was cross feeding).
In his panic he turned them off.
Engines continued to suction feed which had a limit of somewhere around 25 grand and they all flamed out as the climb continued.
We had two RATs...hyrat and elrat...which took a couple of minutes to come on line during which there were no flying controls.
All ended happily and engines got some sort of commendation iirc for getting the engines restarted.

[BEagle]

An ex-BOAC Boeing 707 captain, since passed away, once told me that he'd warned his colleagues not to fly the 'Mt. Fuji tour' when the wind was from the direction it was on that fateful day. Before flying the 707, he'd earlier flown route proving flights to Tokyo in the Comet and had a healthy regard for the weather in that part of the world. He had a lifelong interest in meteorology, so his knowledge would have been better than that of most pilots.

Regrettably his advice was ignored.

[India Four Two]

BEagle,

I had wondered about the decision to fly that routing that day. Even back in the 60s, mountain waves and the associated turbulence were relatively well known.

Given the forecast winds that day, I would have thought an experienced captain would have stayed well away from the lee-side of the mountain, particularly when at or below the summit level.

The summit wind speeds reported in the Flight article were 60-70 kts.

[Jn14:6]

G-AWHU was probably known as 'The Saturn' as it was originally constructed for US carrier Saturn AIrways, hence the -79 (-379C) designation.

[Bergerie1]

I believe the turbulence was caused by a rotor downwind of the summit, but I may be wrong. Does anyone know more about the exact meteorological phenomenon? I know, after this accident, I was always very careful to check the wind when flying near mountains.

[Shaggy Sheep Driver]

Glider pilots exploit mountain wave to heights far above the summit of the mountains creating the wave. AFAIK the destructive turbulence isn't so much the wave itself (which is smooth) but the 'rotor' shear in the associated peaks and troughs. Can anyone confirm?

[India Four Two]

SSD,

I have many years of gliding and towing in the lee of the Canadian Rockies. The rotor occurs downwind of the upgoing air, underneath the "crest" of the wave, where as you said, there is shear between the wave airmass and the underlying air. The rotor is often marked by very ragged, wispy, dark clouds, that are visibly rotating.

The rotor can be extremely rough and quite violent. A very experienced tow-pilot friend of mine used to say "The rotor's not rough until you get rolled inverted!"

Typically, the rotor only occurs at or below the ridge level of the mountain range that is generating it. The largest gust "jolts" I have experienced while flying commercially in the western US and Canada, have been while climbing or descending through the altitude of adjacent mountain ridge lines, on windy days. Based on my "Chipmunk calibrated posterior", I estimate some of them to have been ~2G. Quite scary for non-pilot passengers.

A typical wave-tow consists of flying up-wind through the rotor until you reach the upwind side and then turning to track parallel to the mountain front and climb in the disorganized lift until the air becomes magically smooth. At this point, the glider releases and by the time the towplane has done a 180, the glider is a 1000' or more higher.

The laminar flow in a wave is uncanny. Often the only indication in a glider that you are moving, is the altimeter winding upwards.

PS I've never towed into a wave associated with isolated peaks, but I've seen the so-called "UFO" lenticulars that form downwind of the Cascade volcanoes, like Mt. Rainier. I would image the rotor associated with those waves might be even more violent, because of air coming around the mountain, as well as over it.

Here is a nice time-lapse video of cap clouds and lenticulars at Fuji, although the labelling at the beginning is wrong. What is labelled as "Rotor Cloud" is the stack of lenticulars, marking the laminar wave. The actual rotor can be seen as fast moving wispy clouds, just above the foreground ridgeline. There is a good example at 0:25:
RXFjosCx0n4

I expect the day of the BOAC accident would have been a "blue wave day", where there was not enough moisture in the airmass to form clouds.

[Bergerie1]

India Four Two,
Thanks for your description. When you have a conical mountain rather than a mountain chain, is it possible to have a rotor trailing downwind rather like the vortex off a wing tip?

[India Four Two]

Bergerie,

You can get something called a Karman Vortex Street, which is different from a wingtip vortex. See the very nice animation under Analysis here:
https://en.m.wikipedia.org/wiki/Kármán_vortex_street

And here is real-life example:
https://upload.wikimedia.org/wikipedia/commons/3/3f/Vortex-street-1-90deg.jpg

[Bergerie1]

India Four Two,

Thanks. Yes - I have seen those before. What I was wondering about was the possibility of having a powerful horizontal vortex downwind from the shoulder of a conical mountain.

[Shaggy Sheep Driver]

India four two, many thanks for your instructional explanation of your experiences with wave and rotor. Most interesting. I've even nicked it for my blog! I hadn't realised that rotor usually doesn't exist above summit line.

[India Four Two]

Bergerie1,

I don't know the answer. I'm making some enquiries.

SSD,
Thanks for the compliment. Plagiarism is the sincerest form of flattery. ;)

[washoutt]

Bergerie1, I would expect not. A wingtip type vortex is related to pressure differences in a vertical plane i.e. top and bottom of a wing in an airstream. I can't imagine a mountain causing such a pressure differential. Just my instinct.

[megan]

A U.S. Navy A-4 Skyhawk that was sent up shortly after the accident to search for the wreckage encountered extreme turbulence in the accident area. The aircraft registered peak acceleration values of +9 and -4 "g", causing temporary loss of control, and leading the pilot to believe his aircraft would also break-up in the turbulence. The pilot regained control and landed safely, but the aircraft was grounded for post-flight inspection by maintenance personnel.

[ICT_SLB]

Mount Rainier is visible from Boeing Everett on a clear day and I can remember two lenticulars forming just inland being pointed out to me by one of the local glider pilots. It's a wonder that a similar accident hasn't happened as it seems to be common practice to route flights over the mountain.

[Shaggy Sheep Driver]

But as I-42 pointed out, the destructive rotor which caused the accident only exists at or below the height of the mountain, unlike the wave (indicated by the lenticulars) which can be many times summit height but is non-destructive.

[brakedwell]

Didn't the same 'upside down switch' scenario apply to at least one 1-11 on the BEA fleet? It (or they) were different to the rest having been acquired when another airline was merged with BEA?

I seem to remember G-ANCD, one of 4 Britannias in IAS, having the "reversed" switches. It was built originally for Northeast in the USA, but never delivered to them. It was a 307 with a grey flight deck interior and an accident waiting to happen with all those switches.

[India Four Two]

The aircraft registered peak acceleration values of +9 and -4 "g",
Megan,

When you are not expecting it, that would be staggering, even for a fighter pilot!

ICT_SLB,

Lee waves are very common all over the western US and Canada, when the wind direction, topography and air masses are conducive to their formation. They routinely extend into the stratosphere. The Canadian glider altitude record is 34,400' (Cowley, AB) and the US record is 49,000' (California City CA). At altitude, the wave flow is laminar and very smooth. Turbulence is unusual. The risk of turbulence increases at lower levels, at or near the mountain tops and so it is typically during climb and descent that commercial aircraft encounter.

However, the turbulence, while uncomfortable for the passengers, hardly ever reaches the "severe" classification. I've only experienced severe turbulence on a couple of flights, for very brief periods.

The turbulence associated with the Mt. Fuji accident was extreme. It would certainly make me think twice about flying downwind of a volcano.

I live in Calgary, about 50 nm downwind of the Rockies. On "blue wave" days, with no lenticulars, it is quite common to see the contrails of E-W jets appearing and disappearing as they fly through the peaks and troughs of high altitude waves.

[Shaggy Sheep Driver]

I remember years ago being in the jump seat of a 737 to Tenerife South. The island, dominated by its volcano, Mount Teidi, was visible for many miles as we approached from the north, and the wind was southerly.

I remember the captain being wary of 'what the mountain might be doing' and we gave it a wide berth as we ran down the east coast of the island some miles out.

[India Four Two]

the destructive rotor which caused the accident only exists at or below the height of the mountain

SSD,
I was rereading the accident report and I was surprised to see that the 707 was at 16,000', more than 3000' above the summit, which is higher than I assumed. However, this was clearly a day with unusual and extreme conditions.

[KMSS]

But as I-42 pointed out, the destructive rotor which caused the accident only exists at or below the height of the mountain, unlike the wave (indicated by the lenticulars) which can be many times summit height but is non-destructive.

Such a tragic accident.

Just looking at my glider logbooks. I see a number of flights over 10000' msl in waves from the low ridges of the central and northern Appalachians. I often noted the turbulence as well in my logs. Some of these flights were from airports where the upwind ridges are no more than 1000' above valley level (typically 600-800 msl on the airport).

Very familiar (and satisfying) experience to be working the ragged lift of the turbulent zone well above ridge level, and then climbing into the laminar wave.

Could be the poster quoted above is correct about the rotor zone. I'm not sure if this turbulence I've flown in is strictly "rotor" or how it occurs. I'm just offering a PIREP that it's there, well above the height of the peaks, and wondering about its mechanism...

[blind pew]

Rotor and wave.
Some excellent posts but I would like to add a bit more.
I have hiked Mount Fuji and flown over her. I have also soared three conical mountains.
The first, Hongorie, in the Alp maritine and in a glider.The second south of Auckland when my paraglider instructor imprudently threw me off in an El Nino year when everywhere else was blown out and the third is Sugar loaf in the Wicklow mountains last week.
India 4 2 posts are highly informative and Sugar loaf acted exactly like the Von Karman link on the windward face with the flow oscillating. Sugar loaf is a Marilyn, steeper than Fuji and in a 16 kph pressure gradient flow I was able to soar 150ft above the 660ft mountain - my paraglider has a sink rate of 1m/sec.
Similarly I was able to gain around 50% of the height of the NZ hill in a 30 kph wind (mind you my sphincter was going sixpence - half a crown at a great rate of knots).
Bearing in mind the relatively low Reynolds numbers the airflow over a conical mountain is influenced up to 50% of its height.

Rotor.
As shown in I-42 link it moves and can gallop off downwind...I would imagine there is a ducting effect with it bouncing of inversions.
I have flown in rotor many times and it's best described as being in a tumble dryer. My first trip in the Pyrenees had me spending around 9 hours over four days trying to climb into the wave system.
I had two unpleasant experiences - one where I was knocked unconscious during a transit of the Durance valley on a light wind day...I came too with the undercarriage hanging out and the airbrakes extended. The other was near the Cape gliding club where I found myself inverted at 200ft. There are several members of the club who have managed to put their head through a canopy - one twice.
It was suggested the Steve Fossett crashed due to rotor.
I have also seen a down burst in the lee of Tenerife which terminated 6ft above the road on a day when the wind was blowing force 6.
But I have flown on the lee side of the mountain in a Mistral less than a wingspan away from the southerly face - a technique taught by some of the best french glider pilots - one has to just stay very close and put on a thinking hat as to how and where to leave the lee.
Bergerie would probably remember the loss of a 747 skipper who died in Spain - Vic was one of the few guys who really loved flying and had started hang gliding in the mid 70s when we were both in BEA. He transitioned to paragliders in the mid 90s and was blown back into the rotor above take off at an altitude of 200ft where his wing had a series of collapses (I contacted the investigator). The point of this observation is that the rotor extends practically vertically above the leading edge. I have also witnessed a 200 ft plume of spray above the cliffs of Mohar.

WRT to wave for the curious.
The bars are stationary and parallel with the feature that sets them off. They aren't necessarily at right angles to the wind. I have had a difference of 80 knots on beats soaring the leading edge.
Two features will react similarly to a light interference pattern - the lift can cancel itself out or augment the climb - there is a hotspot over the A1 south of Sutton Bank.
Wave can also be set off by wind shear and there is a theory that cloud streeting is indicative of a sheer wave system. I do know someone who has soared above one side of a street.
I flew yesterday Sleive Gullion which is a part of the Ring of Gullion - either a weathered volcanic ring dyke.
Geology ? Ring of Gullion (http://www.ringofgullion.org/geology/)
In a NNE wind the lower edge throws off a rotor which can make flying interesting...rather curious as it's virtually an edge to a plateau and it's the downwind lip that throws off the turbulence and also forms a wave above the rotor.
To sum up rotor extends far further than many imagine and it can be bloody rough.

[India Four Two]

bp,

Your post was a graphic illustration of how turbulent rotor can be. Scarier events than I have ever experienced. Also, very interesting observations about "conical" mountains.

My experience with rotor has been exclusively at or below the mountain tops. All my wave flying above the tops (up to FL240), has been in completely smooth conditions. I asked a glider pilot friend of mine who is also a commercial pilot, about his experiences and how the autopilot manages in wave conditions. He sent me an extensive, very interesting reply, which I am quoting, with his permission:


Wave effects are quite noticeable. One of the big surprises of jet flying was how often we do see wave, and how widespread it is. Wave caused by strong wind over T-storm lines can be run into every month of spring, summer, and fall. None of the pilots I fly with, recognize the name Cowley [ed. known to glider pilots as "Canada's Diamond Mine"], but everybody knows where I am referring to, if I mention the speed bump on the way from Vancouver to Winnipeg. We often see wave around Thunder Bay, also. Sugarbush is a good place to see wave. I have seen lenticulars over every province, and territory, except maybe PEI.

The effect of wave is two fold - wave and turbulence. We don't see much turbulence due to wave - besides climbing/descending in and out of Calgary. Most turbulence is wind shear generated by the jet stream, although we can get some interesting interaction when a jet stream over-runs wave activity.

The autopilots maintain an altitude hold and the auto throttles maintain a Mach or IAS hold. The autopilots are very assertive about altitude, but the auto throttles are very damped. If I'm too busy to look at the airspeed in some situations, I will just start to push or pull the throttles in the opposite direction to the one they are trying to drive to.

A consideration for most jets is that we run very close to Mmo/Vmo. The other night we were showing an airspeed of 253 kts at 37,000', Vmo was 266 kts, and the stall buffet warning (the speed at which a "g" loading of 1.3 would stall the aircraft) was 231 kts. So, 35 knots between stall and over-speed warnings. At the first feel of the aircraft rising, pilots will put hands on power levers and at 5 knots or so will start adjusting the power, depending upon the rate of acceleration. Excursions of 7 knots or greater will usually see us reset the target speed to the middle of the band. The autopilot will usually hold within 100 feet. If the airspeed excursions start getting greater, we advise ATC and start flying attitude accepting the deviations to moderate the airspeed excursions. Maybe once every year or two, the excursions can be +/- 600' with speed changes of +/- 10-15 kts. The most extreme event I am aware of, was when a friend of mine ran into wave at Cowley and ended up 1600' above initial cruise of FL410 while “sharply" reducing power, and still getting the occasional over-speed alarm.
In a follow-up, I asked him about what altitudes he has experienced rotor turbulence, relative to the mountain tops:

Rotor turbulence will be significantly below the tops of the lenticulars of course. As a rough rule of thumb - coming into Calgary I figure when wave is possible - if it is smooth above 14,000' it will likely be rough below, if it is rough above 14,000', often it is smooth below. And it is a rapid transition from smooth to rough - rarely over 500' vertically. So that is 4-5,000' above the ridgeline tops. Driving further east past the foothills at 16,000' before letting down over the flat land (10 nm) will almost always avoid the majority of the rotor, unless the tertiary lennies are in serried ranks east of Calgary.

There are very interesting theories about the behaviour of single mountains vs ranges in wave conditions - with vortices/and all sort of singularities being identified - but the common thread is a narrow lift band and greatly disturbed flow up to near the heights found along ranges.
Finally, with reference to the Mt. Fuji accident, he made this observation about the relative strength of jets, compared to the towplanes we both fly:

The vertical "g' limits for certification in the transport category are (to a little airplane guy) frighteningly small, being just +2.5 to -1.0, compared to the +3.8 to -1.52 Normal category, and +4.4 to -1.76 Utility category. Both the 182 and Scout are certified Utility category at reduced weight. (Flaps down is +2/-0, but that's the same for pretty well all aeroplanes).

[Bergerie1]

BCal had a severe turbulence incident in mountain wave/rotor conditions over the Andes. You can read about it here:- BCal Flight over the Andes 1 (http://www.british-caledonian.com/BCal_G-ASIX_Flight_over_the_Andes_1.html)

They were very lucky.

[blind pew]

India 4 2... 100% behind your post.
My first experience with wave over the Alps heading South when I was extremely wet behind the ears...I went out to answer the call of nature and when I sat back down noticed the speed was low...added a touch of power and looked at the Doppler map and my nav log...next second over speed alarm went off - only time I heard it on the Trident (but not so on the DC9 with ex Luftwaffe starfighter guys).. I yanked open the airbrakes as per our SOP...complete over kill...supposed risk of tuck under.

Only used the Turb mode on the DC10 with one of those "heros" one occasionally get who dispite Shannon warning us that everyone else had descended below FL300 on the Nat Tracks we had to go through it cause the yanks are whoosies...

Hit the button which disconnected the auto throttle and the FD went into pitch attitude hold mode...both "sir" and engines kept switching the A/T back on...didn't even understand the basics.

The glider I got knocked out was a Phoebus C built by one of the Atafliegs...stress loaded to 12G and the first production glass glider..42:1 which flew the first 300km flight in the UK.
Sadly some of the modern microlight gliders aren't so well built as was at Coupe Icare when one folded and lost a very good mate ex French and American carriers when he had a wing fold near Gap.

[KeMac]

Does anyone know the source of the picture of PFE coming down? I know it was in Macarthur Job's book but it looks as if it must have been taken by someone local who had his/her camera to hand. I ask because I want to trace the copyright holder to see if I can get permission to use it in a book I am writing.

[AtomKraft]

Blind pew.
I have experienced high altitude rotor over the Pyrenees in an airliner and it was not funny at all.
Started at FL380. Climbed to 390 at Mmo/ idle power, followed by loss of I think 5000' with full power and intermittent stick shaker.

:{

It was over a waypoint called TURBO. :ok: I guess there was a clue there, had I only known it.....

Strong northerly Jetstream of about 90kts.

It damaged the aircraft fin cap and scared us both ****less.

Luckily ATC warned us of 'Windshear' over the mountains, so we'd buttoned up the cabin. Was quite a ride though and it seemed to go on for ever.

I let the FO fly it!:E

[Tu.114]

I have tried to find the investigation report of this accident on the web but failed to find anything with the usual suspects like Google, ASN and the Japanese aviation accident investigation authority (where nothing older than the accident to the JAL 747 in 1985 is apparently online).

Could anybody give me a pointer, please?

[megan]

Tu.114, like you I have been unable to source the original report in the past. Should you want, PM with your email and I can scan an article written by a very respected Australian aviation safety personality who would have had access to the originals- Macarthur Job.

[Bergerie1]

Megan,
I too would very much appreciate seeing the scanned document on this crash. I will send you a PM.

[rjtjrt]

like you I have been unable to source the original report in the past. Should you want, PM with your email and I can scan an article written by a very respected Australian aviation safety personality who would have had access to the originals- Macarthur Job.

The 3 books, Air Distaster 1, 2 and 3, by Macarthur Job, are fascinating books, well worth acquiring.

[blind pew]

Like you I was once scared ****l@ss over the Pyranees or rather to the north...Cruise level probably around 300 as in SR we often flew lower than optimal for crew and pax comfort as well as shorter block time.
It was gin clear without any obvious wave signs and in a DC9.
Was a "life changing" experience as had always been frightened of turbulence but was going through a rough time with the Mrs and thought "well at least if the wings fall off I won't have to back to her nagging"
With that alternative perspective I've never been frightened since...

Early in my time of flying for the Swiss I pointed out to a skipper that with the forecast of severe turbulence over the Alps we should route around them, two weeks later our ops manual was changed as previously it had stated no operations into areas of forecast or observed severe turbulence.

But had it once with a "star" on the DC 10, westbound on the Nats after we were informed that everyone had descended to below 300 because of the actual turbulence. Despite me being the flying pilot our hero decided that the yanks were woosies and we ploughed on. 'Twas the only time I used the turb button, "Sir' and the eng kept leaning forward and reengaging the auto throttle as neither of them knew what the mode did or what to do. (Fly attitude with constant cruise thrust).
As my instructor at Hamble said (ex hurri ground attack) "severe turbulence is when you get eyeball bounce and can't see the instruments".
Nowadays it's when my wing folds and reinflates with a bang...time to land ;-)

[Chris Scott]

Interesting you got such mountain waves at FL300, blind pew. That was presumably a very long way below the trop? After our VC10 incident in the lea of the Andes in 1971 (even "accident", in terms of the substantial damage), BCAL realised that the mountain waves may be at their worst just below the tropopause. So on the EZE/SCL leg we flew at least 8000 ft below it, particularly if there was a big difference in the QNH between Mendoza and Santiago. IIRC, Swissair and KLM or Lufthansa had already sussed out the problem.

Safe flying in the rotors (rather you than me)...

[blind pew]

What I have learnt in twenty years of gliding and paragliding is that the atmosphere is made up of homogeneous "packets" that don't mix and that the boundary layers are the source of turbulence.
There is also a channeling effect - a bit like ducting with VHF.
I was very lucky a few years ago with a setting sun on my local mountain when the sea breeze wind started to increase.
I didn't understand it at the time but had enough of flying and decided to spiral down to top land near my Jag only to find myself flying backwards...
After survival mode kicked in I passed three landing options going backwards to land vertically in a blackberry bush and a 25ft pine tree at the edge of a plantation saved me getting seriously hurt.
It took the best part of an hour to extract my paraglider and another hour to retrieve the motor which gave me enough time to figure out the cause.
Which was the inversion was acting as a Venturi with the ground as the other wall.Whilst the sea breeze was decreasing the Venturi effect and the mountain were forming a choke.
I only did the Andes once on the Death Ship...a turn around ex Rio to Santiago..and with light winds it wasn't a problem and I had never heard of Bcals tropopause theory but it makes sense with the wave system bouncing off the layer.
What still surprises me is the lack of communication between disciplines (and companies).
One that comes to light is an ex BEA skipper who I knew who signed off on an Airprox..GASCO..concerning a chopper and a paraglider..biggest load of Rubbish but then in a previous life he was forced to resign after leaving a stick of Semtex on a 747 for a couple of weeks which circum navigated the globe until found by a cleaner (IIRC) - the Semtex...even he couldn't loose a 747!