And you think you're good!! <Old Crash Comic Article>

[Dogimed]

Consider the following near catastrophe from over 20 years ago in western New South Wales, involving a single pilot on a low capacity RPT operation.


As his near-new Piper Chieftain was established on short final at Brewarrina with four passengers, the pilot selected full flap at about 200ft. A Chieftain’s flaps are actuated by a single electric motor turning a spindle drive to the flap on either side, where a small fibre gear wheel engages with a larger gear wheel to actuate the flap.

When both flaps were fully extended, the drive gear on the right flap moved away from the larger actuating gear because of a worn spindle, and its teeth were partially stripped.The resulting loss of gear engagement caused the right flap to be fully retracted by aerodynamic forces. The flap motor microswitch is on the right side, so that the fully retracted right flap cut the power to the flap motor, preventing retraction of the fully extended left flap. The left flap was providing such a powerful right aileron force, despite full opposite aileron and rudder, that the aircraft began banking to the right. The pilot immediately applied full power to both engines and selected gear up to abort the approach, but despite full opposite aileron and rudder and full trim, he was forced to reduce power on the left engine to prevent the bank angle from continuing to steepen towards
the vertical. The drag induced by the extended flap and the necessarily crossed controls was seriously limiting aerodynamic performance.

While gingerly exploring these unwelcome handling characteristics at close to treetop height, the pilot quickly determined that if power on the left engine was reduced to prevent over-banking to the right, the remaining available power was insufficient to maintain height. Additionally, although full power on both engines would provide a slight climb, this could
only be sustained for a short time before the angle of bank became dangerously steep. The pilot was faced with an aircraft in a continuous turn to the right. A power reduction reduced the angle of bank, increasing the radius of turn, but caused the aircraft to descend; while full power produced a steep climbing turn,which could only be sustained for a short time. Alternating
between the two produced a flight path consisting of a series of arcs joined by small loops.

Fight to clear:Any attempt to get the aircraft back on the ground would depend on manipulating the available power to achieve a flight path to a suitable landing place, where the aircraft could
be aligned with a clear landing path. The terrain – tall river gums – a crosswind and single runway at Brewarrina, made it unlikely that the aircraft could be successfully aligned with that runway. The pilot, still fighting to clear the trees, decided to try and reach Bourke, 50nm to the west,with its two runways and more hospitable surroundings.He planned to do this by making
his long descending right turns while on westerly headings, and his tight climbing turns when the flight path had taken him too far to the right. He was also aware that there was likely to a physical limit to the length of time he could handle the strain of holding full right rudder and aileron. While wrestling with his desperate situation, the pilot was also arranging for his passengers to sit on the left and secure their seat belts.
Simultaneously, he operated the fuel crossfeed to draw fuel for both engines from the left outboard tank. This created a lateral weight imbalance, while ensuring both engines were
operating at full rich mixture to reduce the weight of fuel in the right wing, and help counter the aerodynamic roll forces of the
extended flap. Also aware that extended cowl flaps produced a slight lift effect, he ensured that the right cowl flap was fully extended.

Well aware of the mechanics of the failed actuator gear, the pilot then called Dubbo Flight Service.
He recalls: "The Brewarrina agent had already called Dubbo and told them I had swerved off the landing and was tearing around
the bush like a scrub turkey that had swallowed a packet of tacks. I assured the operator it wasn't too funny, and got him to ask our engineers to come to his radio room with the electrical
systems book, because the circuit breaker was okay, and we might be able to nut out some way to get electrical power to the flap motor. “As it happened, they confirmed there was no way we could do that. Meanwhile I can recall we were getting near the river, where the trees are taller, and a couple of times I had to concentrate on fitting the aircraft between two tall trees.Another wild climb, and I had a brief talk to the passengers.
“By continually switching power configurations, I was able to gain a little height, and I’d worked out how to get some control over the flight path. Eventually I got into a configuration where I had enough power on the high engine to stop me turning so quickly, and the circles were getting bigger. Instead of circling around in a steep turn I’d been able to reduce it to a medium bank, but I never got much better than that all the way to Bourke. By the
time I got to Beemery, halfway to Bourke, I was high enough to clear the big power lines.”

By now, the pilot was planning his approach to Bourke and his own account is graphic:“The shift of weight had made the turns a bit shallower and the circles a bit bigger. I had time to think of ways of landing without first digging a wingtip into the ground, which could finish us. “It was all very messy to work out, but I had to have a plan to go by. I’d have to fly the aircraft onto the ground at 120kt, but fortunately Bourke has a long runway. I’d put the gear down at the very last moment, and I’d know within seconds whether we’d roll onto both main wheels or stand on a wingtip. “I planned to straddle the left runway lights, so the right wing would be on the bitumen, where it wouldn’t catch on the runway lights, bumps, sand or grass, and the drag from the
sand on the left gear might help us keep straight. I’d also have to kick the nosewheel straight before it touched, because if it was still turned hard left it would be torn off.

“I came around in my last turn, put the gear down as the runway was coming into line, pulled the top engine power right off, and pulled back on the wheel as the plane sank towards the runway.The gear locked down just as the right wheel and wingtip touched together. “There was a little squirt of sparks out of the wingtip on the sealed runway, then the wing came up, about a foot above the runway.When the wheel strut compressed with all the weight, there was another tiny burst of sparks, but the wing lifted again.
“We did quite a run on one wheel with the 350hp right engine on full power for a long time before the left wing started to drop. Off came the power, and we dropped onto both wheels. I let the nose wheel fly straight before it touched.”
The aircraft had taken over an hour to travel the 50nm to Bourke, and used almost the entire 1,830m of runway before stopping. It was later found that this event was the fourth in a Chieftain; and that the other three, in Israel,Mexico and Brazil, had all been fatal.

Amazing.

[Arm out the window]

Fantastic, hat off to this bloke.
Very cool and thorough under pressure, obviously, and you've gotta love the comment about the scrub turkey that swallowed the tacks!

[kiwiman]

I apologise in advance.....but I am feeling extremely pedantic today.......

"And you think you are good" OR " And you think you're good"

........thank you....I feel better now...........where are those pills......

[Dogimed]

kiwiman,

Cant change it on the big ol title thingy.

If thats all you got out of the story, I hope you drive trains for a living.

Dog

[Woomera]

......................:E

[kiwiman]

No. Great story! Long for someone with a short attention span like me - very long!

[Dogimed]

Thanks Woomsie!


Dog

[Chimbu chuckles]

Very well done indeed..wonder what he's doing now?

Reminds me of the story of the chaps in a Falcon 10 at, I believe, Sydney many moons ago.

Runway electric trim went full nose up causing uncontrolable pitch up on A/P disconect....as the aircraft reached some terrifying nose high attitude the PIC rolled on 90 degrees of bank and let the nose slide down below the horizon, rolling winds level before starting back up again...all of course with max nose down pressure on the control column..while the F/O frantically searched for the CB and then manually adjusted the trim back towards neutral.

Two classic cases for the pro handflying skills/ recovery from UA training case....sometimes, not very often but sometimes, manual skill and calm critical assessment are more vital than FMC skills.

[Dogimed]

I believe he wrote a book, however I am yet to find it.

I think it may have been a Mr Daley?

Dog

[ovum]

Please correct me if I'm wrong, but I thought the micro switch limiting the up and down travel of the flap in the PA31 is in the left wing?

[Sharpie]

Chuckling Chimbu!

Great story and in fact I spoke to the skipper of that Falcon only yesterday afternoon (He now resides retired in France) and he assured me that he would send me his story in the next couple of days to post in pprune.

C.C. What about the F28 on short final rway14 at Jacksons POM that had the lift-dumpers deploy after the gear was extended!

The aircraft experienced a rather high rate of sink very quickly and the crew avoided landing short only by rapid positive actions on their part.

Then that other one of a few years ago that happened I think to a Zlin doing aerobatics in UK?
A wing started folding and the quick thinking pilot rolled the aircraft on its back, carried out an inverted approach until very close to the runway, rolling back normal way up and landed as the wing did fold.

[Chimbu chuckles]

Can't for the life of me remember who the F28 skipper was (Billy Spencer?) but Tim, the FO who saved the day when he saw the lift dumper dolls eye roll over to 'out' (or whatever it used to say...up?) as he armed them in the gear down scan is now a Captain with VB....prolly still a formidable drinker too :ok:

They must have been VERY close to hitting the ground...and Fokker's response...sorry can't happen!! Wasn't it Malaysian engineers who had rewired them wrong during a D check....can't imagine PX engineers being so silly....they wouldn't have worked at all had they been tampered with by the PX lads ;):E

The Zlin story is from the 60s....very famous ex RAF test pilot and aeros champion subsequently killed in a CFIT ferrying a HE-111 (actually Merlin engined Spanish licence built version-CASA 111?) from Spain to Britain for the filming of Battle of Britain...Neil Williams. He subsequent to the Zlin wing folding escapade spent a CONSIDERABLE time 'long haus sik' recovering....the wing did fold after rolling back right way up on VERY short finals...but even then he was 20' up else the wingtip would've not cleared the ground on the roll...of course...still pretty clever bit of aviating.

I'd certainly be interested in a first person account of the Falcon 10 trim runaway.

Chuckles:}

[Contract Con]

Gday all,

Great stories all of them. Keep 'em coming!

The asymetric flap ones are always an eye opener, especially mid base or on final!!

Woomera, would it be against "the rules" to name names of pilots such as those above and those featuring in equally "interesting" events in aviation?

Great skill and judgement deserves to be recognised.

Pleasant to see this forum used for the greater good rather than the normal cr@p and mudslinging!:ok:

Cheers,

Con

[Sharpie]

Chuckles, Here 'tis.

Sharpie.


Dear Peter,

As per our conversation, below is my recollection of the events of 20th September 1987 in the Falcon 20F at Sydney Airport.

The story commenced at 140 feet above Runway 16 (now called 16 Right) at Sydney Airport on a normal visual, manual approach and landing. There was a slight rain shower on medium to short final. The Pilot Flying (PF) was in the right hand seat and myself, as the Pilot In Command (PIC) was in the left hand seat.

The body angle of the aircraft seemed to flatten and the PF mentioned the term wind shear. Our speed was VREF +20 or 25, we checked again gear and flap positions.

The PF stated that things were wrong and he was going around, power was applied and loss of pitch control followed immediately. I took over the control of the aircraft and I can still recall the alarming pitch attitude we had and saw the Indicated Air Speed drop below 107Kts. I had both my hands holding the control column fully forward trying to limit the rearing of the body angle. My concern was that we were going over on to our back which would have been the end,as this manoeuvre started at about 80 to 90 feet AGL. In my mind was that the vertical lift of the aircraft had to be minimised so I rolled it to the left in a very steep turn and had the PNF close the throttles to assist me in getting the nose of the aircraft to come below the horizon. This turned out to be successful and we recovered prior to ground contact. As power was restored the nose pitch attitude reached again the 60 to 80 degrees (as some eyewitnesses claimed).

During the first go around the flaps and gear were retracted and we did a series of the above manoeuvres, using the roll and power off and on application technique as described above, each time gaining some height above ground level, although we had very limited heading control.
We did this for about 5 or 6 times and obtained about 6500 feet AMSL. During this time I was unable to take either hand off the control column or relax the force required to limit the rear of the body angle. The PNF was completely occupied with the closing and opening of the throttles to help me semi-control the nose position.

During the initial loss of pitch control I glanced at the trim indicator which appeared to me to be in the normal range. I did not see the red light "on" for an aft stabiliser condition. My own efforts of trimming with
the normal system did not initially help the situation.

The aircraft then "flew out" of the problem and returned to normal operation, with no further input from the crew.

The aircraft position was now North East of Sydney and we returned for a landing at Sydney, Runway 16, using 10 degrees of flap. The landing was successful.

Some brief comments: a) Once the first recovery had been achieved, I knew that I could control the aircraft to a certain extent whilst the fuel lasted.
b)This could not have been possible without the excellent crew co-ordination between PF and PNF.
c) A help to me was the knowledge of aerodynamics instilled by instructors during my early training on Tiger Moths.
d) The aircraft had a single electric trim system, they now have a dual system to try to prevent the possibility of dust causing relay sticking problems.
e) Immediately after this incident we made arrangements for the CVR and FDR to be forwarded to the BASI for their investigation.
f) At a later date, after the BASI investigation, we simulated the problem in a flight simulator which was spectacular!
g) The ATC assistance during the incident was of the highest order.

We were both lucky to come back from this incident to tell this story and I hope that any other crew faced with an immediate, critical situation work as a team and do not give up.


Mike.

[dogcharlietree]

07 Jun 93 Amazing flying skill: Piper Navajo G-BMGH;
Aircraft Accident Report 6/94, published by the Air Accidents Investigation Branch of the Department of Transport, United Kingdom. Piper PA-31-325 C/R Navajo, G-BMGH 4 nm south east of King's Lynn, Norfolk on 7 June 1993.

SYNOPSIS

"The aircraft was operating on a scheduled passenger flight from Birmingham to Norwich, with a pilot and seven passengers on board when, as the flight passed south of King's Lynn, there was a loud 'bang' and the aircraft immediately rolled to the right and entered a tight spiral dive, or spin. The loud bang was caused by a blade, that had detached from the right propeller, penetrating the aircraft's nose baggage bay and exiting through the upper left fuselage structure. This blade then struck and removed the front of the left propeller assembly. The right engine tore away from the wing, precipitating the loss of control, and the left engine stopped. The commander managed to regain control of the aircraft and successfully carried out a forced landing in a field of cereal crop. All eight occupants evacuated the aircraft with no serious injury."
Note, the UK AAIB states;
"The commander managed to regain control of the aircraft and successfully carried out a forced landing in a field of cereal crop."
However, when BASI wrote an account of this accident in the November 1997 issue of their Asia-Pacific Air Safety magazine, they say;
"Miraculously, the pilot managed to regain control of the aircraft ...."
intimating that there was some "divine intervention", and nothing at all to do with pilot skill.
The UK AAIB investigation identified the following as among the causal factors:
i) Separation of the right engine, as a result of massive out-of-balance forces following fatigue failure of the right propeller hub and associated release of one blade, caused an immediate and critical loss of control which was only recovered and a successful forced landing accomplished by the exceptionally skilful handling of this commander.

Another great example of superb airmanship by a professional aviator. Well done.

[Sharpie]

...and then there was Don Erceg NZ topdressing pilot whose 180 threw a blade before totally removing the engine.

With pole held full forward by use of knees, full nose down trim, the aircraft floated down a la falling leave and just before it was going to impact on a cliff face, Don let everything go, covering his head with his arms.

A wee updraft lifted the aircraft up a few feet with the result that it landed(?) on ther cliff top with no further damage.

It is reputed that when Don phoned the engineers to advise that his engine was missing, they told hiim to bring it back to base and they'd check the maggies and plugs!

[Chimbu chuckles]

I had remembered hearing he was badly hurt but found this first person account...seems not.

By Neil Williams - British Aerobatic Team member
1970 World Aerobatic Championships, practising at Hullavington
The weather at Hullavington was good, with 2/8 of cumulus based above 3,500ft, 1,066m. The wind was south-easterly, 5kt to 10kt and there was no turbulence.

Because there were three static balloons flying in front of ATC it was decided that we would use runway O5/23 as datum and fly on sorties over the grass parallel to that runway. This would keep us well clear of the balloons and the wind was so light that it did not pose any problems.

Two Zlins were operational that day, with three pilots. I had flown one sortie and took off on the second with full fuel tanks at 11.35 a.m. The sequence was flown twice through satisfactorily, and the aircraft was climbed for the next and final run through. Everything progressed normally until the completion of the fifth figure. which was a vertical climbing half roll, half outside loop to a vertical dive and pull out to level flight at about 1,000ft, 300m. During this pullout, as the nose came up to the level attitude, with 5g indicating. There was a loud bang and a severe jolt was felt through the airframe.

I have heard eyewitness reports in which the aircraft is said to have "staggered". That is perhaps the best way to describe the immediate sensation following the failure. At the same instant there was a sudden and very peculiar increase in slipstream noise. and I found myself leaning against the straps to the left although, as I looked left, the aircraft appeared to be flying level. I had reduced power and centralised controls instinctively at the first signs of trouble.

The reason for the sensation of being pulled to the left was very soon apparent. Although the left wing was flying more or less level, the rest of the aeroplane was rolling left around the failure point. At this stage there was some degree of control over the aircraft, which was by this time beginning to lose height. I throttled fully back to reduce speed and thereby reduce the flight loads, but this caused the nose to drop further. Dihedral was increasing steadily and the roll and yaw to the left were becoming progressively more determined. Full power was then applied in an attempt to get the nose up, but this had no effect at all on the situation. By this time the aircraft was outside the airfield and losing height fast. It was my intention to try to keep the wings as level as possible and to try to achieve a shallow flight path with the intention of arriving, if possible, right way up in the most convenient field available. It was, however, apparent that if control was being lost at that rate, it would have gone completely before reaching the ground. In fact all control was finally lost at about 300ft, 91m.

At this stage the aircraft had turned left nearly 90° from its original heading, and was banked 90° to the left (at least the fuselage was). I thought the wing had folded to about 45° but it was probably less than that, if one takes into account the fright factor. Full right aileron and rudder were being held on and the throttle was wide open as the bank reached 90° left and the nose finally dropped. The sideslip was very high, and the instinctive reaction to pull the stick back only worsened the situation. I had heard a report from Bulgaria some years ago where a top wing bolt had failed on an early mark of Zlin whilst under negative g and that the aircraft had involuntarily flick rolled right way up, whereupon the wing came back into position, and the aircraft was landed by a very frightened, but alive, pilot. I had guessed by this time that a lower wing bolt had failed and that I was faced with a similar situation, albeit inverted.

It seemed that if positive G had saved the Bulgarian, negative G might work for me. In any event, there was nothing else left to try. I centralised the rudder, rolled left and pushed, still with full throttle. The wing snapped back into position with a loud bang. which made me even more concerned for the structure. Immediately the negative G started to rise and the nose started coming up. Altitude was very low by this time and I had no instrument readings at all. For just a moment I thought I was going into the trees, but then the nose was up and the machine was climbing fast, inverted. I was just beginning to think that I might make it after all when the engine died. I checked the fuel pressure - zero. A check around the cockpit revealed the fact that the main fuel cock had been knocked off. This could possibly have been the result of the jolt which accompanied the initial failure. I think I was probably thrown around in the cockpit and may well have accidentally knocked the cock then. I selected reserve fuel and almost immediately realised that this position would take fuel from the bottom of the gravity tank, which was of course now upside down. I therefore re-selected main tank and after a few coughs the engine started and ran at full power.

Inverted circuit
I was quite low again by this time and initially started to climb straight ahead. I then turned back towards the airfield and continued the inverted climb to 1OOOft, 305m. By this time, the remainder of the team had been very quick off the mark and had alerted crash facilities. I throttled back to conserve fuel as I knew the gravity tank was only good for about 8 minutes safe inverted flight. I then turned the aircraft in steady flight and held the stick between my knees (no aileron trimmer) whilst I used both hands to tighten my shoulder harness even more. Had a parachute been carried I would have climbed as high as possible and used it.

I then considered using undercarriage and/or flaps, but rejected both. Flaps were no use to me whilst inverted, and I could not fly right way up anyway. Also if only one flap extended it would cause an immediate loss of control. The undercarriage required more thought. If I could make an inverted approach with a last minute rollout and if the aircraft arrived on its wheels damage might be minimised. However, if the gear fully or partially collapsed the aircraft might turn over. Also, and this was the biggest argument against, the Zlin undercarriage usually extends with a fairly solid thump.

I did not know exactly what damage had occurred and I was concerned in case the strain of lowering the wheels might remove the wing altogether. It was just as well that I left thewheels up, because the failure was not the wing bolt after all, but in the centre section inboard of the undercarriage leg.

I also considered four possibilities for landing, namely, inverted ditching, deliberately crashing inverted into trees to take the impact, inverted crash-landing on the airfield, or an inverted approach with a last minute rollout and hope for the best.

The last seemed to hold the best chances for survival, but I then decided to experiment to see which way was the best to rollout; if the rate of fold of the wing was sufficiently slow it might have been possible to exercise some control over what was obviously going to be a belly landing (I hoped). A rollout to the left was attempted, and the wing immediately started to fold, with the result that the inverted flight was quickly re-established. The rollout to the right was not investigated, as the left wing was obviously being weakened by these manoeuvres. Also the supply of adrenalin was getting rather low by this time.

A wide inverted circuit was made for the grass strip parallel to runway 23. As the crosswind was insignificant this afforded the best approach, clear of buildings and balloons. The threshold was crossed at 112 m.p.h., 180 k.p.h. at about 200ft, 60m with the throttle closed. Petrol and switches were left on in case it was necessary to overshoot; also the canopy was retained, since I did not want my height judgement affected by slipstream. The possibility of a jammed canopy was considered, but the hood is very light, and I felt that I could break my way out if necessary. A slow inverted flare was made and the aircraft was levelled as near to the ground as possible.

Low, low rollout
As the speed fell to 87 m.p.h., 140 k.p.h. a full aileron rollout was made to the right, and just a trace of negative G was maintained in order to hold the left wing in place. The aircraft responded well to the controls at this stage, but as it approached level flight the left wing started to fold up again. The nose was already down as a result of the slight negative G, and subsequent examination of the impact marks showed that the left wing tip touched the ground during the roll, although this could not be felt inside the aircraft. As the wing folded the aircraft hit the ground hard in a slight nose down, left bank attitude. I released the controls and concentrated on trying to roll into a ball, knees and feet pulled up and in, and head down protected by arms. I had a blurred impression of the world going past the windscreen sideways and then with a final jolt, everything stopped. I released the harness, which had done a very good job, and then found that the canopy had sprung 6in, 15cm open and jammed. I didn't bother to investigate this, as the petrol tanks had split! I gave the canopy a resounding blow and it flew open first time. I felt mildly surprised that everything was still working as I evacuated the area, and having decided that the aircraft was not going to burn, and having also collected some semblance of breath and composure, I returned to the aircraft and made all switches safe. The crash services were on the scene very quickly, which was most encouraging. Fortunately they were not required.

The aircraft was a complete write-off, but on reaching into the cockpit and checking the, seat, it was as solid as a rock, all the straps were intact, and on moving the control column, both ailerons worked in the correct sense. True, there was a failure, but it is a tribute to the Czech designers and engineers that the aircraft could be flown at all.

It was a nasty experience, but a lot can be learned from it, notably that the aileron was acting as a geared tab, as the wing folded. This resulted in the left aileron being pulled down, since the aileron rods were intact, and as the wing moved, the aileron was applied without any movement of the stick. Any attempt to apply right aileron merely worsened this situation. I could have saved myself a lot of problems by rolling left immediately the failure occurred. It seems also that the damaged wing must be towards the ground during any rolls, either in or out. The ability to fly over an airfield with crash facilities is absolutely essential. This time assistance was not required, but lives have already been saved by this.

This situation may never be repeated but if such an accident does occur again the information in this account may be useful.

I hope it will never be needed.

From Flight International - 18 June 1970