Spinning an Airliner
 

Just wondered if it was possible, say a Dash 8 or 737

:ok:

I would worry more about whether or not it could be recovered from the spin if you did succeed. :\

I'm sure it's possible. Not sure I'd want to be in it when it happened however.

Tragically it's been proven to be possible in the 707, as some RAAF aircrew found a number of years ago during asymmetric practice (RIP gentlemen, you're still missed).
That topic's been well discussed so I don't want to open it up again, but yes, at least some types will spin.
As with any machine, the weight distribution, configuration, power settings, speed and so on must influence a type's propensity to spin.

Spinning airliners
 

Sure - I reckon the usual laws of aerodynamics aren't that corrupted or negated by scale, so if you can get to a sufficiently high angle of attack, and you can overcome the natural directional stability, it'll spin. A Dash 8 was lost a few years ago in south west UK, spinning following loss of control during a Vmca check on an air test - like the 707 above. My guess is the only reason it doesn't happen very often is that airliners spend much less of their time at low speed/high AOA than military jets, and very little time indeed in being manoeuvred under those conditions. Also, depending on the CG position, control power may be limited, making it difficult to get to a stall AOA without applying forces and stick displacements that are markedly different from those seen in normal operation.

Playing around with Vmca is bound to lead to trouble eventually. An RAAF Hercules in 1960 did a three turn spin before recovery following a Vmca situation during dual conversion. The aircraft was badly damgaged and almost a write-off and in fact Lockheed were interested in exactly what spin recovery action the pilot took as there has been previous spin accidents in Hercs and the aircraft failed to recover. There have been numerous cases of light twins going into a spin during Vmca "demonstrations" - or should we say cock-ups.

Lockheed P-3 departure
 

http://www.safetycenter.navy.mil/med...05/spun_it.htm

There is a departure recovery procedure in the NATOPS manual - so it must have been tested.

Worf

I bet
 

I bet Tex Johnston could do it. I know Bob Hoover could. Probably without spilling his tea, either. (R-click 'n save to see why I hold these beliefs...) :ok:

I bet too!

That most mediums to heavies would break and toss off engines early into a developing spin.

I suppose it's quite possible...
 

Never really thought about spinning a big airplane, but I'm sure it's possible. All you need is a stall in uncoordinated flight, and it'll happen.

The problem with multi-engine airplanes is when you're one engine inoperative...and a stall occurs. If under given conditions, a stall occurs before Vmca (i.e. the stall speed is greater than Vmca), the wings will stall before the aircraft uncontrollably rolls. (This assumes the flying pilot manipulates the controls in a proper manner and maintains coordinated flight.)

Conversely, if Vmca is greater than the stall speed (under the given set of conditons), the plane will roll before the wings stall.

In either of the two above situations, you'll not spin. It's when the two speeds are close to or equal...that's when you soil your panties. She rolls uncontrollably (you're in uncoordinated flight), and the wing (or wings) stall. Yep, you'll get a spin.

So, in Vmca demonstrations, you need to see what speed you'll stall at and then be careful about power/speed combinations to make sure she doesn't roll at or near that stall speed.

Many of the test pilots have the advantage of chutes to assist in stall/spin recovery. As we all know, during training and check rides, many unrecoverable spins inadvertantly occur. What a shame...

Tom

Not exactly an airliner, but an exec twin that failed to make the UK register - the Mitsubishi MU-2. I was investigating stalling speeds in various configs after some lower than scheduled speeds were found on a C of A airtest, and carried out several airtests after ground checks and engine / airframe adjustments. Finally everything seemingly possible had been checked and a/c should have been perfect. On the next airtest the aircraft auto-rotated at the stall (power off & clean) despite immediate full opposite rudder. The spin developed fully and showed no sign of recovery using 'standard' techniques. There wasn't too much time available as entry to the 'stall' had been 5000ft amsl (normally sufficient as recovery usually only lost a few hundred feet at most) and ROD was off the clock estimated 6000fpm.
I could write a chapter on the next 20 seconds but I'll be brief. After trying in/out-spin aileron (spoilers on MU-2) unsuccessfully, time was running out fast and, in desperation almost, I smoothly increased to max power on the in-spin engine. After about 5 seconds of oscillatory spin the a/c flicked into a spin in the opposite direction which I arrested after about 1/2 to 3/4 of a turn. Resumed symmetric power after closing both levers and recovered at 1000ft above the sea.
Not an experience I'd like to repeat - fortunately I was pretty recent on spinning, having completed 2 years with the Rothman's Team about a year before, my specialist solo manoeuvre being the lomcevak.
Training spins are usually entered by applying pro-spin rudder from level flight (or from manoeuvre) - this one went unprovoked and with corrective inputs. Later extensive investigation revealed an engine problem that caused a slow insidious loss of power on one power plant with no cockpit indications. It would take too long to explain the MU-2's controls and aerodynamics, but the effect of this power loss was, on a 'trimmed' a/c, to reduce the stalling speed by about 7kts and set up all the conditions required for a spin.
Lessons? 1. The UK CAA were absolutely right in not certifying the type and 2. I was wrong, with hindsight, to fly to the actual stall (less than scheduled) - better to stop the exercise at Vs and report 'no stall'. 3. Not a good idea to have a fleet of 1 odd-ball aircraft. If there'd been another similar type in West Africa we could have compared flight characteristics.
rts

Great clips, and very impressive, I believe he could too.:ok:

Hoover's flying is superb, and the reason his show is so impressive (without being terrifying) is that it is sooooo smooth - He knows his survival depends on keeping the airplane in the regime where airplane/control response is approximately linear. I believe the only airplane he spun in shows was the NAA F-86 Sabre.

As well-thought-out is the dead-stick Shrike Commander routine, his P-51 show closer (touchdown on the numbers - pullup and roll - land & stop on the remaining runway) is REALLY convincing. :ooh: :cool:

Spinning A340
 

I've heard that if you disonnect enough of the Protection Factors in an A340 sim that it does quite an impressive spin. Not sure about the real a/c.

Does the simulation include failing the engine pylons due to centrifugal G's?
:eek:

I'm with you there barit1. I wouldn't say anything to detract from the excellence of Bob Hoover or Tex Johnston, but rolling and spinning cannot be compared. I doubt if either of these 'aces' would have been stupid enough to consider a deliberate spin in a 707. A well executed barrel roll is harmless to an aircraft (though if screwed-up one of the greatest height losers - Bullock (RIP) A26 Biggin Hill), but a spin has many other forces (centrepetal, sideslip etc) and I seem to remember early 707s were quite prone to shedding pods with quite small amounts of sideslip.
rts

Barit + Rod, agreed.
One of the 320 sims we use does an impressive manoeuvre if you apply standard spin initiation, but I would call it a spiral dive rather than a spin. That might be because of the physical restraints of the jacks.
We learn a lot from sims eg: 'would the REAL aircraft do that?'. Usually the answer is 'yes'.
Not, I fancy, in the case of spinning.

I would be utterly astonished if any commercial aircraft simulator had an accurate representation of the aerodynamic forces and moments in an actual spin, given the almost total absence of any data whatsoever on which to based the modelling. It's a flight regime where little or nothing can be extrapolated to from normal linear aerodynamics, and to actually build a realistic spinning aerodynamic mathematical model is not a trivial task by any stretch of the imagination. (When I was at BAe we had post-stall/spin models for the Hawk, but I don't think any of us would have considered them other than a general representation of the aircraft's behaviour, and that was WITH the benefit of large amounts of flight and wind tunnel data to base the models on)

Got me thinking about this one now. My immediate reaction was agreement to the statement about engines falling off if a big jet did spin, but then I thought about it some more. First, the rotation rates are probably going to be lower - big inertias to overcome with aerodynamic forces. Second, IAS will be low - the average airliner doesn't have fighter power to weight ratios and will almost invariably be at low speed at spin entry, either because the pilot stuffed up some low speed handling (e.g. Vmca) or generated more drag than thrust in the manoeuvre leading to the stall. The structural loads are dependant on dynamic pressure, i.e. square of IAS. The average airliner is designed to cope with, for example, an engine failure at max IAS that generates significant sideslip by the time the usual allowances for yawing moment due to asymmetric thrust, directional stability, and for the average pilot to react to same and apply corrective control have all been applied. The resulting structural forces would have to be pretty significant compared to those generated at the low speeds seen in a spin, even allowing for the higher sideslip angles, because they're proprotional to the square of the speed.
That said, the above relates best to airliners with jet engines: I reckon the gyroscopic effects on big propellors would be way more whacky, so I'd tend to agree with the earlier assertion about losing engines if you want to go spinning a C-130 or P-3.

Ref Fantoms post, allegedly some Arse tried the same manoeuvre in a B777 sim and the box attempted to launch itself off the jacks and into the coffee shop next door. Left , right , left , right, hats off interview with no tea and bickies.

Teadriver, I can't access the accident report now, but the RAAF 707 I mentioned above did have engine pod or pods separate in flight as it spun (only from about 5000 ft if I remember right).

wanna spin?
take something like a 737, fail some slats on one side, put it in a std rate turn an slow it down.

Oh ask Hoot Gibson how he did it that 727-100.

Teadriver -
"A Dash 8 was lost a few years ago in south west UK, spinning following loss of control during a Vmca check on an air test"

..... the aircraft was a Dash 7 (VP-CDY). The airtest was for a 3-engine climb for C of A renewal. Schedule called for Flap 25, Eng #1 shut-down, Eng #2, 3 and 4 Take-off power, climb at V2 (80kts at planned weight). Unfortunately the Flaps were left at 0, and the aircraft stalled at 90kts. Aircraft descended at a high rate to impact. AAIB report states that it is not possible to state whether the subsequent path was a spin or a spiral dive, as the recorded "g" suggested a spiral dive, but the low IAS suggested a spin. Full aft elevator was held throughout the descent, and full power on 3 engines also kept almost to impact. CVR was u/s, findings were based only on FDR recordings.

Report is available on AAIB website

Thanks KenFoggo... I'm still LMAO about the B777 sim trying to shake itself to pieces... Good one. I have some spin experience but not enough to be an authority.

I recall a Channel Express F.27 freighter had it's cargo shift aft on approach and it went into a flat spin. There was something similar about a BAC-111 spin test in which the spin parachute was of no help. Were these flat spins indicative of heavy aircraft characteristics or just reflective of the special circumstances.

Roethesod about the Mu-2 which I have never flown personally, I gather they all have some difficulty with power levers (constant speed pitch levers)down between the pilot's seats being vulnerable to being knocked or having a friction nut deficiency. I gather that it is not uncommon for one of the power levers to retreat without the pilot noticing.

This plane is a well known widowmaker and the issue seems not with the engines, but with deficient power levers.

I would add my voice about the structural failure risk to airliners. Engine pylons are designed to shear if the engine seizes, or when torque is too great. Remember the L-188 Electra (a la spinning a C-130/P-3) had speed restictions imposed because at 400kt the engines shook off their mounts. Engine mounts were never designed with strength in sideways motion.

Kiwiguy,
I think the unfortunate F27 suffered a C of G issue and, when the final stage of flap was selected, became uncontrollable in pitch. I don't remember anything about a 'flat spin'.
As I recall, a BAC 1-11 was lost during a flight test programme concerning stalling and had nothing to do with 'cargo shifting' or a 'flat spin'.
In my hazy recollection, the Mu-2 was denied British certification as (perhaps, inter alia) a consequence of the forward window integrity not meeting British requirements. I would hesitate to refer to a type as 'a well-known widow-maker'. Unless, of course, you have private, unlimited income to support an expensive libel case.
Just my humble opinions, of course.

I didn't say the BAC-111 crash had anyhting to do with cargo shifting. You're making that connection yourself.

I referrred to the Channel Express F.27's cargo shifting rearwards. At the time Flight International published a photo showing the aircraft landed flat and did not strike nose first. I seem to recall mention of a flat spin.

In terms of the BAC-111 crash I read an account of the crash many years ago stating that it was in a flat spin at impact. Even without black boxes it is usually evident from the impact whether the impact was flat or not.

With regards to the Mu-2 many pilots will not fly her and have an apprehension of it because of it's accident rate. Fair comment. If Mitsubishi want to draw attention to the claim with banner headlines, so be it, but I think they have better things to worry about.

In many respects I actually like the Mu-2 design. If it has flaws then it is appropriate for the professional pilot community to discuss this. Many aircraft designs are pretty fantastic but have a single flaw which damages their reputation, for example the Comet 1 with square windows, or the L-188 Electra which vibrated it's engines off until it's speed was limited to 350kts.

Pity aircraft manufacturers would think to sue before thinking to rectify something as simple as power levers.

The problem we had with our MU-2 was nothing to do with power levers, I don't recall ever experiencing the 'wander' you describe. We had what was described as a 'torque shift'. I don't pretend to understand the Garrett 'single red line' instrumentation system, but what we actually experienced was a slow reduction in the starboard engine torque over a long period of time (100s of flying hours) so that, at the time of my airtest there was 10 - 12% less torque with identical on-board engine indications. Our investigations prior to the said test flight were extensive and included blade angle, idle fuel flow, flap spoiler and trim-aileron rigging checks etc. The engine malfunction was only discovered when we had the actual torques checked with a Le Beau (apologies for spelling?) meter, a device which is fitted between engine and prop - not the kind of equipment normally held by a small fleet. As far as I know Garrett had never advised that the torque gauge indications could be totally meaningless (100% torque was 100% of what was available on an engine, nomatter how sick and underpowered it was, it seems).

I agree with your appraisal of the aircraft's safety reputation and I may be wrong but I never heard of any pilots being sued by Lockheed for calling the F-104 a 'widow-maker' (fwiw a very fine aircraft in my opinion). Many MU-2s were lost in the USA prior to my complaints to Mitsubishi about its asymmetric handling characteristics. The AFM quoted Vmca as 93kts in those days (1984-ish). We complained about difficulties our trainee pilots were having with EFATOs and were asked 'at what speed did we make the 'cut'?' When we told them 105kts+ they were amazed and said 'NEVER BELOW 125kts'. It appeared that the low Vmca was there to sell the aircraft's short-field performance. We suggested this and that they review their AFM. Probably the fastest AFM ammendment on record followed and the Vmca was increased to 115kt IIRC. We immediately ceased our Nigeria MU-2 operation and sold the aircraft (which had been bought specifically for VIP flights into a performance limiting field after thorough AFM study).
rts

Like I say, I haven't flown the Mu-2 and just base my observation on what friends have told me about their experiences on it. What you say about torque differences makes a lot of sense out of the problems with that type.
My friends blamed the power levers.

I think you'll find that the BAC 1-11 was in a deep stall (T-tail blanked so no elevator authority.) TP kept the running commentary all the way down.

The BAC 1-11 G-ASHG was sadly lost to a Deep Stall, the Anti-spin/anti-stall shute was not fitted. Another 1-11 G-ASJD forced landed on Salisbury Plane with the chute attached and streamed.. This aircraft was repaired and flew on becoming XX105 of the RAE/DERA/Qinetq.

M5DND

It was actually during a flight demo over Lake Washington during Aug. 1955 hydroplane races. Thousands of people witnessed it:

http://www.historylink.org/output.cfm?file_id=390

BTW - Tex Johnston lived to the ripe old age of 84 before dying of Alzheimer's.

Spinning larger aircraft
 

The Indian Airforce back in day one spun the Bristol Freighter, and wrote back to the manufacturer asking for correct spin recovery technique!
2:
A B747(Classic) did a one turn spin when the crew failed to observe an Autothrottle disengage, and the bird slowed up in Alt Hold untill too late it auto rotated.
They used the gear to control the huge speed excursion on recovery, lost the gear doors and limped into LAX.
The aircraft was flown home (orient) about a year later after Mr Boeing did one or two repairs.
The crew Paxed home with out expenses or a future in aviation.

The Air China incident wasn't a spin, the pax described high g loads for extended periods of time, similar to a spiral dive or badly executed barrel roll. No chance for the engines to separate! Besides, the report makes no mention of a spin, just a roll. Granted, the aircraft probably exceeded Mach 1 in the recovery :uhoh:

Confabulous,

I absolutely agree with you; I first thought spiral dive because of the high speed and high G loads, but having read on I go for the barrel roll which, without an initial pull up, rapidly becomes a barrel roll in the down vertical as demonstrated fatally by Don Bullock in the A26 Invader at Biggin Hill.

I Ford,

The structural damage is consistent with high G loads. There are no high G loads in a stable spin (IAS too low) although pilots have been known to follow a spin recovery with a spiral dive - but not in the Air China incident. I still think an early 707 would have shed pylons (due to sideslip loads) if it had been spun.

Regards,

rts

Wasn't there a TAROM A300 which got into a spin about 10 years back? I recall the crew recovered from it at a fairly low altitude, there even was a video about the incident but I can't put my hand on it.

Anybody?

TTF

Treetopflyer the FDR animation of the incident which I believe that you refer to shows that the aircraft did not spin. There was a pitch up during go-around due to the crew over-powering the autopilot (no force disconnect) which caused excessive nose up (auto) trim. The aircraft ‘rolled-off’ the top of a very nose high wing over (>90 deg roll). Although the airspeed was less than stall speed, the ‘g’ level, and presumably the AOA were low. The aircraft repeated the manoeuvre before the crew regained control.