The Partenavia unexplained accident at Essendon in 1978

[Centaurus]

The No 59 tram from Airport West to the CBD parallels Matthews Avenue as is it travels South towards Niddrie. Passengers seated on the left of the tram can just see the threshold of Essendon Runway 08 on the left and Cameron Street on the right. Houses are situated most of the way on the west side of Matthews Avenue stretching from the suburb of Airport West to Niddrie. I travel the route often on my way to Niddrie Public Library and as we pass Essendon Airport, it brings back memories of an aircraft accident that cost the lives of a young family.

It was into some of these houses on the night of 10 July 1978, at 1853 hours, that a Partenavia P68B crashed with three crew aboard. It had departed from Runway 26 with the intention of executing a simulated engine failure after take off followed by a circuit and landing. The simulation was by cutting the mixture control of the starboard engine at 200-250 feet above ground level at the same time the wing flaps were retracted from setting 15 degrees to UP.

Seconds after power was re-introduced on that engine the Partenavia adopted a six degree nose down flight path until colliding with houses on Matthews Avenue. The aircraft caught fire immediately which resulted in the deaths of several occupants of the house. The crew of the aircraft survived.

The cause of the accident was that the aircraft became grossly out of trim at a height which did not permit time for the crew to effect recovery. The manner in which the out-of-trim condition occurred was unable to be determined and the possibility of a trim system malfunction cannot be eliminated. However, the more likely explanation is that the command trim switch was activated unknowingly.

See the following accident report:

https://www.atsb.gov.au/media/24632/197802547.pdf

Inadvertent elevator electrical trim use when practicing an emergency is a an event most flying instructors may have met at some time in their instructing career. This usually happens when the electrical elevator trim button is situated on the control wheel and the pilot's thumb may be resting close to the switch. It can happen in times of stress and is not noticed until a severe out of trim is felt.

For example, a case occurred recently when a go-around was attempted in a Boeing 737 flight simulator. The stabilizer trim switch is thumb operated on the pilot's control wheel. As part of the go-around procedure, full power may be applied and at the same time the aircraft is rotated up to an initial pitch attitude of 15 degrees. The flaps are then normally retracted from landing flap to 15 (close enough to be the equivalent of half flap in a general aviation type aircraft.

The combination of under-slung engines delivering high power and the pitch up to 15 degrees gives a very marked pitch up moment well beyond 15 degrees if allowed to happen. Pilot action to contain the rate of pitch up includes forward pressure on the control column backed up by appropriate forward selection of stabiliser trim to contain the forces applied to the elevator. A Cessna 172 or most light singles have a similar pitch up characteristic when full power is applied in the landing configuration.

In the case of the Boeing 737 incident in the simulator, the pilot under instruction held his thumb forward on the stabiliser trim much longer than necessary and the result was the aircraft eventually bunted over and dived into the ground. The stabiliser trim wheel of the 737 makes a loud clacking noise when operated (a design feature to alert the crew). At the time of the go-around the aircraft was on autopilot. When the pilot disconnected the autopilot, a warning siren sounded which he failed to cancel.

The noise of the siren was so loud that it disguised the clacking noise of the moving stabiliser trim and this was missed by the student. This all happened together in a time of increasing stress caused by the late go-around. It shows these sort of unexpected events can occur in any aircraft type.

A similar thing happened to a Boeing 737 of Flydubai Airlines that crashed during an IMC go-around at Rostov-on-Don, Russia, in March 2016,that killed all on board. See link below

https://en.wikipedia.org/wiki/Flydubai_Flight_981

[josephfeatherweight]

The crew of the aircraft survived.
That sounds amazingly lucky!

[Band a Lot]

That sounds amazingly lucky!



If I had my finger on that switch, I would have wished one extra did not survive - maybe not every day but many.

If that were the case.

[Old Akro]

Alan Baskett retired only a few years ago and is still alive and healthy. He was at the Casey airfield reunion at Moorabbin a couple of years ago. He was an outstanding and respected instructor. I was an early student of Speedair at Essendon having followed him there from Casey in Berwick.

The ATSB report does not cover the mandatory AD that resulted from Partenavia as a result of this accident to limit pitch trim travel.

The report is inconclusive as to whether it was runaway trim or inadvertent trim activation by the pilot under supervision. It was told to me at the time by the crew that it was runaway trim that they were physically unable to manually over-ride it. The report acknowledges this and the Partenavia AD is witness to this.

In my opinion, a factor that should have been considered,. but was not, is the poor town planning which did not align a street with the runway or provide any public open space that would provide additional safety off the end of runway 26.

[john_tullamarine]

I don't know if Alan still posts .. he PM'd me at one stage after a comment I made in the long-winded Essendon thread. Had a quick look in the history but was unable to identify the PM to check if he still posts.

Only flew with him several times .. including an endorsement on the Partenavia in question a while prior to the prang. He appeared to be quite a straight down the line operator and, certainly, a pleasant chap with whom to interact about the airport.

[Deaf]

Always wondered about that one especially regarding a failed TO of a Partenavia at Melton the previous year. BASI said the unable to get airbourne was due to 50 (lbs/kg?) overweight.

[Ethel the Aardvark]

the P68 has a pretty average trim system. it relies on the tension of the cable around the trim wheel to stop any slipping and has no physical cable lock. therefore if you move the trim to each stop and continue to operate the trim wheel it will misalign the indicator with its actual position.
I have seen pilots hold the trim wheel and operate the electric trim which slides the cable around the trim wheel and misaligns the indicator as well.
I used to check the correct alignment before every flight which takes about 2 mins.
for those that don't know gently trim full nose down, outside align the stab with the neutral rivet, stab trim should be level or slight down.
the fuel system is an even greater marvel of engineering and can cause accidents if not treated correctly.
thankfully been a while since I have had any involvement with the partbanana

[First_Principal]

the fuel system is an even greater marvel of engineering and can cause accidents if not treated correctly.

Oh yes, it certainly has! This report (http://www.taic.org.nz/ReportsandSafetyRecs/AviationReports/tabid/78/ctl/Detail/mid/482/InvNumber/2002-006/language/en-US/Default.aspx?SkinSrc=[G]skins%2FtaicAviation%2Fskin_aviation) is worth looking at, although I think it says rather more about the driver and the training system than the aircraft fuel system...

FP

[Ia8825]

It doesn't help that they seemingly re-designed the fuel system for each individual aircraft, and the differences can be very subtle as well

[Ethel the Aardvark]

biggest problem I have heard of was after maintenance the fuel selector knobs were not installed at the correct positions, there is no master spline and can be fitted in potentially 20 odd positions due to its design, if the control cable tubes are not lubed then the selector drives slip as well throwing it out. hope the new ones are better!

[Seagull V]

And then there was this incident in January 1992. See http://www.atsb.gov.au/publications/investigation_reports/1992/aair/199201201/ (http://www.atsb.gov.au/publications/investigation_reports/1992/aair/199201201/)


While the title "Hard landing" is quite misleading there are some aspects of this event that appear to relate to original post i.e. Loss of elevator control.

[ramble on]

IIRC the accident killled 4 children their mother and grandmother. It was so tragic.

I used to pass the little brown roofed house on the block years ago wondering if the childrens father was still alive.

The block was recently subdivided and a second house built on it.

[Centaurus]

biggest problem I have heard of was after maintenance the fuel selector knobs were not installed at the correct positions, there is no master spline and can be fitted in potentially 20 odd positions due to its design, if the control cable tubes are not lubed then the selector drives slip as well throwing it out. hope the new ones are better!

Thread drift from original subject of trims. Some years ago there were several Partenavias at Essendon. I recall trying to turn the fuel selectors to their various positions while teaching a student. They were all unacceptably stiff to operate and sometimes needed two hands. I went across the tarmac and tried the same with the other Partenavias. Same defect. I wrote the defects up in the MR much to the annoyance of one operator. I was told it was a well known characteristic with these aircraft and to accept it.

Later I read a UK accident report where a Partenavia was en-route from the Channel Islands to an airport in southern England when an engine failed. I forget the finer details but the female pilot went to use the cross-feed system but was unable to physically move one of the fuel selectors into the cross-feed position. The aircraft was ditched due inability to cross-feed and some passengers were drowned. The pilot survived to tell the tale. The Brits CAA issued an AD that warned of the danger of Partenavia defective fuel selectors.

I contacted BASIS in Canberra with a copy of the AD and evidence of my own experience with Partenavia fuel cock selectors. BASIS then issued a similar AD to Partenavia owners. In brief it required pilots to write up instances of difficult to move fuel selectors and maintenance organisations to check them on scheduled servicing cycles.

Then one day a Partenavia arrived for a 100 hourly. An LAME mate rang me and said come and have a look at this Partenavia which was undergoing other rectification. He said try to move the fuel selectors. They were jammed completely and had obviously been like that for yonks. In fact the problem was at the other end near the engines - not the selectors themselves. He suggested to his supervisor that DCA airworthiness people would be interested and should be advised as a standard procedure in view of the AD. The supervisor told him to forget that idea as the aircraft owner might get upset and go to somewhere else for future servicing.

[Stationair8]

Is it just me, but are these BASI reports posted by Centaurus a lot better than today's piffle written by the current crop of experts?

[Centaurus]

Is it just me, but are these BASI reports posted by Centaurus a lot better than today's piffle written by the current crop of experts?

Which is why I believe today's pilots can learn from these old BASI/DCA accident reports without being ambushed by the plague of political correctness that regretfully pervades much of our Public Service reports

[advo-cate]

Is that due to the MOU [Memo of understanding] between casa as well as deficient reporting by atsb??

Only speculating!!

[Old Akro]

Is it just me, but are these BASI reports posted by Centaurus a lot better than today's piffle written by the current crop of experts?

You need to read the old Aviation Safety Digests!!! The facts from decent investigation, plus the real world judgement from someone like Centaurus.

[Lookleft]

What's been learnt though? Whether the report was written by BASI or the ATSB pilots are still going VMC into IMC and crashing, pilots are still running out of fuel and crashing and pilots are still mishandling engine failures in twins and crashing.

[D B Cooper]

Please excuse the thread drift, but with regard to the Partenavia at Moorabbin in 1992, does anyone recall if a nosewheel change was carried out on that aircraft not long before that which involved a number of people sitting on the tailplane? Or was that a rumour?

[6317alan]

Special InvestigationReport79-1


This Accident Investigation Report prepared by the Dept while appearing to be extensive and detailedin its investigation of this accident is in fact deficient in its pursuit of the subject matter to its logical extensionof the ramifications of the total assessment of all the facts.
The Dept have touched on the matter of pilot strength when they investigated control system failure caused by pilot input loads but choseto not detail in a similarmanner the requirements of FAR 23-143(c) which limit the force requiredto be exerted by a pilot on a temporary basis not to exceed 75 pounds
This report also omits to detail any reference to the fact that the position of the trim tab actuator was in a position that indicated that the trim tab travelwas other than that certified in Australia
This report omits to admit to the fact that the Dept failed to obtain flight test reports as required by ANO 101-22 prior to certifying the Autopilot/Electric Trim system.
This report omits to detail that the Trim Tab Travel Range was excessive to that required to comply with FAR23-689(f) which establishes total trim capacity requiredfor an aircraft.
This report fails totally to address the fact that the Electric Trim System was never flight tested correctly as required.
This report by not completely investigating all aspects of the Electric Trim System was able to minimize the design and certification deficiencies to enable the claim of pilot error to be raised by stating
“However,the more likely explanation is that the command trim switch was activated unknowingly.”
This cannot be supported by any supported by any evidence as the coroner found at the inquest.
The CAUSE as listed in this report is incorrect and misleading and would be more accurateif listed similar to the following.-
Cause
The cause of the accidentwas that the aircraftbecame grossly out of trim at a heightwhich did not permit time for the crew to affect recovery.The trim system design allowed control forces to be generated that exceeded pilot control force limits to be exceeded by a substantial amount. The manner in which the out of trim conditionoccurred has not been determined and the possibility of a trim system malfunction cannot be eliminated


All this was only achieved after many numerous legal orders were obtained as the Department did everything they could to stall and delay proceedings.
I think their tactic was to maximize the delaying tactics hoping that I would tire of the whole process and just go away.
I had to get a court order to get them to let me get copies All the documents were laid out on a conference table in a boardroomin no logical order.I then had to identify he relevant documents that I required to be copied. It ended up taking a full days work to sort out.
In the end I ended up accepting an offer as I had been made aware that if I didn’t,Legal Aid would withdraw their support and I would be on my own from a financial point of view if I didn’t accept what was on offer. So reluctantly I accepted and at the end of 1993 after repaying the workers compensation costs and paying my legal costs I received what was left.
[email protected]

[Centaurus]

Cutting the mixture in order to induce an instant failure was normal procedure among general aviation operators in those days and considered perfectly safe. Even to this day, the technique is still used by some instructors to simulate engine failures at low altitude in multi-engine aircraft despite CASA published material warning of the inherent dangers of student mishandling. The subject has previously been extensively covered in Pprune pages.

Surprisingly, the wisdom of mixture cutting an engine soon after take -off at Essendon that took place over the immediate built up area was not mentioned in the accident report. Maybe because in that era, the risk of mis-handling by a student was considered by many to be minimal.
However it was sheer bad luck in this case where the combination occurred of mixture cut engine failure happening simultaneously as flap retraction was occurring and the strong inference that the student froze on the trim switch due to stress of the moment at night. As the saying goes, "Sh*t happens." But it sure picked the wrong time to happen on that night..

[Centaurus]

Adding to the subject of an unexplained accident - in this case the suspicion that a trim tab was involved - was that of an RAAF MB 326 Aeromacchi jet trainer that in 1969 crashed under mysterious circumstances near the mouth of the Avon River close to RAAF Base East Sale.
https://www.google.com.au/search?source=hp&q=Macci+jet+trainer&oq=Macci+jet+trainer&gs_l=psy-ab.3..0i13k1l2.1715.21551.0.22042.19.19.0.0.0.0.447.3803.2-13j0j1.14.0....0...1.1.64.psy-ab..5.14.3795...0j46j0i131k1j0i46k1j0i10i46k1j46i10k1j0i10k1 j0i13i10k1j0i13i30k1.7XrURbyK1XQ

The aircraft was on a low level cross-country exercise with an instructor and trainee instructor aboard. Some minutes after departing East Sale and close to the area of the Avon River the aircraft was seen by witnesses to suddenly pitch up almost vertically, then dive into the ground. Both pilots were killed. There was no radio calls.
Investigators discovered there had been a history of Macchi unexplained elevator electrical trim operation during previous months both at East Sale and RAAF Base Pearce in WA. One example at East Sale was where a trainee instructor flying from the back seat was in the climb shortly after lift off when the aircraft pitched up violently. He immediately let go of the controls because he thought the instructor in the front seat must have seen another aircraft or a bird and taken avoiding action. The instructor in the front seat felt the aircraft pitch up and instinctively took over control to avoid a stall. The cause of the pitch up was never determined.

On another occasion a Central Flying School instructor was testing a trainee instructor for his instrument rating. During a recovery from an unusual attitude on instruments the aircraft went into a steep dive from 15,000 feet. Both pilots stated the aircraft was vertical passing 10,000 ft with them joining to pull back hard on the control column to recover. Recovery was completed at 1500 feet agl. In each case the elevator trim tested normal on the ground

The Macchi trim control was a `witches hat` switch on top of the control column operating elevator and aileron trim tabs. A test flight was carried out to see how quickly a pilot could react to an uncommanded elevator trim change. During level flight at 200 knots and 5000 feet the Macchi was flown with the pilot in the front seat and the investigating officer in the back (instructor position) seat. The plan was the investigating officer was to operate full back elevator trim without notifying the pilot while the aircraft was in level flight. The purpose of the flight was to see how long it took for the elevator trim operation to take effect and the action of the pilot once he detected the change of trim.

Initially there was a slight pitch up followed within seconds a violent pitch up as the trim reached full rear stop. The recovery action from the steep nose up attitude required the pilot to quickly roll the aircraft to 90 degrees angle of bank towards the nearest horizon in order to get the nose to drop and then use ailerons to level the wings.

This recovery action mirrored witnesses reports when they saw the crash of the Macchi near the Avon River. That is to say the aircraft was seen to roll hard in one direction as it reached a vertical climb and had the wings level in the ensuing dive recovery but too late to avoid ground impact.

Until the cause of the Macchi trim defect could be established, steps were taken to disconnect the trim tab to one elevator on all RAAF Macchi trainers. In turn this would lessen the chances of loss of control if only one trim tab was operational and ran away. It was about two years later when an airman at Pearce was doing a walk-around inspection of a Macchi prior to a night flying exercise. He had switched on all external lights as part of the inspection and that included the anti-collision rotating light. To his astonishment he saw the elevator trim tab oscillating in tune with the rotation of the anti-collision light. Further investigation revealed a crushed electrical loom inside the fuselage adjacent to the tail-plane. The mystery of the uncommanded elevator electrical trim operation had been solved. Following rectification, all Macchi elevator trim tabs were later returned to service.
P.S. Centaurus happened to be the DFS (Directorate of RAAF Flying Safety) investigating officer.

[zzuf]

IIRC there was another contributor to Macchi longitudinal trim incidents.
A number of pilots experienced strong nose down trim change, with almost uncontrollable control forces, while accelerating in a dive just after spin recovery. The cause was found to be that, during a spin, the trim switch could contact the pilot's harness buckle and apply full nose down trim. The stick force used to hold pro-spin control inputs and the low "q" during the spin resulted in full nose down trim deflection with no noticeable stick force changes.
It became clear that the Macchi longitudinal trim system had far more authority than required to be able to trim the aircraft for the full flight envelope and weight/cg range.
The RAAF had previous experience with the runaway of electric trim system (with excessive authority) with the Canberra. Apparently the message of the risks of high authority electric trims combined with reversible control systems was forgotten.

[6317alan]

"Centaurus" is missing the point completely by concentrating on the engine failure exercise! The aeroplane crashed with full power applied and full nose down Trim applied! Even if the trim system had run fully down the pilot should have been able to overcome a total force of only 75 lbs! The Department had not met their own
requirements for flight tests and certified an aeroplane that did not meet FAR23-143c

[zzuf]

While I no longer recall the certification basis or FAR23 amendment status applicable to the Partenavia, I am unaware of any FAR23 handling or controllability standards, past or present, which are conducted at the trim travel limit. FAR 23.143 does not require this.
Reaching the trim limit in flight should only result from pilot action. The failure mode and effects analysis of the trim system should show that a trim runaway is highly unlikely and must not occur in case of a single failure.
The Australian regulator certificated FAR23 aircraft under bilateral agreements, it was rare to conduct any flight testing.
However, in the case of the Partenavia, the stalling speeds hence Cl max appeared optimistic cf similar aircraft. Tests were done to determine the accuracy of the pitot static pressure corrections. Further, the importer decided to re-run landing distance tests, possibly as a result of the pitot static tests.
It would have been a nonsense to do a completely new certification exercise on the dozens of new types / models arriving in Australia.

[6317alan]

The first PN68 was certified in Australia had no Autopilot fitted, the next 2 arrived had Autopilots fitted The Department asked for flight tests as required by ANO 101-22 this was bypassed! After a trim runaway at Moorabbin a Modified to SB41 aeroplane the Department then finally in 1989 carried out flight test CAA Document M131-515-4 which proved that technically even with the SB41 fitted the PN68 still does not meet FAR23-143c
If the Department had done their job 6 innocent lives would not have been lost

[zzuf]

6317alan, it is now not clear to me, aka I don't recall, if the Partenavia electric trim system should have been tested for control forces over the operational speed/cg range at full trim deflections or by virtue of the trim operating cable diameter tested by runaway, recognition, reaction tests.
Not knowing the cert basis and not having access to FAR 23 and AC23 at the appropriate amendment status makes it difficult to follow all the investigatory work you did.

[Deaf]

Alan may correct me here but IIRC it was not a student but a three monthly check flight for a pilot qualified for night twin ops.

At the time student visual circuits could not be done at EN so ex EN usually done at MB

[Old Akro]

At the time student visual circuits could not be done at EN so ex EN usually done at MB


Bacchus Marsh

And limited circuits were possible on request.

[6317alan]

Pilot Flying was rated NVMC and needed 3 take-off's and landings to remain current. EN required IFR for night circuits at that time so I acted PIC so P/F was AICUS. Essendon banned Night Circuits after the Partenavia went berserk. Geoff was a very responsible experienced PPL. I was there to save him from needing to fly to Mangalore to do his 3 circuits to remain current
"He did not operate the Trim Switch."
I believed him and so did the Coroner! I have no memory whatsoever of the Accident!

[CharlieLimaX-Ray]

Talking to another pilot about this thread, and he mentioned that some of the early Partenavias were a bit poor on quality control inspections in the factory. Didn't this one, have washers missing on the engine mount bolt's, and this was found during the accident investigation?

[scrum]

I am enjoying these posts of yours Centaurus. Well written and thought provoking.

[MagnumPI]

Wow what a thread. Certainly the first I have been in where one of the crew has posted about their experience.

6317alan, a question for you if I may - how hard was it to get back in the air after the accident? Have you ever felt vindicated? Can you remember anything at all from the flight?

[6317alan]

Magnum PI, Answers to your questions, I have absolutely No memory for a fortnight after the crash although I got all the questions correct on admission form at Royal Melbourne Hospital, so therefore I had no problems other than the Medical branch creating problems after I had repassed a Medical in getting back into the air. No memory has ever returned! "Natures way of looking after me I Guess"
I have been very much been vindicated after the accident by Geoff who was medically U/S a little longer than I, and he can remember it vividly, He got me to check him out after his medical clearance, however I have never felt vindicated by the Department. They still try to push the Party Line with ATSB Report 1-79 as can be seen in the first post. The only way to stop this is to separate the accident investigation from the Regulator completely!
Alan

[6317alan]

My Report PDF.pdf (http://www.pprune.org/attachment.php?attachmentid=2864&stc=1&d=1503544974)

[MagnumPI]

Thanks for answering my questions 6317alan. Keen to read your report but the link doesn't work - maybe try uploading to Dropbox and posting the link here?

[john_tullamarine]

Keen to read your report but the link doesn't work

Try now .. the site, as of a while ago, requires the attachment to be given a tick. As a consequence it might be a few hours until someone spots it and does the deed.

[6317alan]

I'm working on it back soon!
AB

[zzuf]

6317alan
1. What was the diameter of the trim operating cable?
2. What was said about the statement in AC 23 (23.689(f)) that the maximum prolonged forces of FAR 23.143 are not applicable in a failure case and would be considered too low?
3. Were runaway tests carried out or simply control forces at full tab deflection?

Unfortunately without documents at the appropriate amendment status any attempt at following the saga is problematic.

[6317alan]

My Partenavia Report

Partenavia P68B aircraft autopilot
and trim systems

Prepared by Alan C Baskett

introduction On the 10th July 1978 the Partenavia P68B VH-PNW crashed at Essendon Airport. The Dept in their Special Investigation Report 79-1 of March 1979 list the cause as:

Cause The cause of the accident was that the aircraft became grossly out of trim at a height, which did not permit time for the crew to affect recovery. The manner in which the out–of–trim con- dition occurred has not been determined and the possibility of a trim system malfunction cannot be eliminated, however the more likely explanation is that the command trim switch was activated unknowingly.

The coroner at the inquest because of the evidence could not accept the DEPT’s more likely explanation. The DEPT’s simplistic assessment of the cause of this accident
is an easy way of minimizing the underlying design deficiencies, which allowed the aircraft to “become grossly out-of-trim” and the DEPT’s mismanagement of its certification responsibilities by attempting to shift the cause of the accident to “pilot error” This report attempts to detail the history and modifications made to the trim tab travel range of the trim system and the auto- pilot/trim system and of the certification and approval of these modifications.

summary of events

23-1-75 First of Type Certification in Australia of P68b Air- craft (no autopilot fitted)

April/May Two P68B arrive in Australia with 1975 Autopilots fitted and no certification

23-5-75 The Dept. formally requests certification justification for Autopilot installation
12-6-75 R.A.I. Autopilot Approval No 124-245-T
1-8-75 to Edo-Aire Flight tested Autopilot 12-9-75 installation.

15-9-75 Edo-Aire issued S.T.C. no SA 3067SW-D for Auto- pilot/Electric Trim system installation

Sept. 75 Australian approval of Autopilot/Electric trim system installation

28-4-76 Partenavia produce Autopilot flight tests BM 82 and BM 83

20-7-76 VH-PNW registered in Australia with TTTR Number 2 fitted

23-11-76 TTTR Number 2 certified by FAA type data sheet A31 EU Revision 3

16-1-78 R.A.I. Certify TTTR Number 3 in RAI Type Data Sheet SO / A151 Revision 5

10-7-78 Date of the said Crash

October 78 S. B. 41 modification to TTTR Number 4

March 79 Special Investigation Report 79-1 published

17-2-89 The Dept. flight test P68B aircraft as per CAA docu- ment M131-515-4 and in doing so establish TTTR Number5

NOTE FAA is USA Federal Aviation Authority R.A.I. is the Italian Aviation Authority STC is an FAA Modification certification Meaning, Supplementary Type Certificate

Partenavia P68B aircraft and autopilot electric trim installation history

The original P68 aircraft and the P68B aircraft were both certified originally with a trim tab travel range of 36 degrees (TTTR No One) in fact this was the only trim tab travel range approved in Australia until the requirement for S.B. 41 became a mandatory modification late in 1978 after the said date. The first P68B aircraft arrived in Australia during 1974 after Forrestair entered into a distribution agreement with Partenavia. This aircraft received “First of Type” certification on 23-1-75 for Australian operation.

IT WAS NOT FITTED WITH AN AUTOPILOT/ELECTRIC TRIM SYSTEM!

During April/early May 1975 two aircraft arrived at Essendon after ferry flight from Italy, both these aircraft were fitted with Edo-Aire Century 111 Autopilot / Electric Trim Systems. During the regis- tration/certification process the Dept. noted the autopilot installa- tion and requested the Reg .27 justification for these non-approved modifications. This justification was first sought verbally and then in writing from the Dept. to Partenavia on the 23-5-75. In the mean- time Forrestair were required to disconnect and disable the autopilot installations in these aircraft, leaving Forrestair with two aircraft paid for by them but unable to deliver to their customer and receive payment for until completion of the autopilot installation. Partenavia obtained Italian certification from the R. A. I. for the Autopilot/Electric trim system installation, RAI approval No 124, 245 / T on the 12-6-75 more than a month after the two aircraft had arrived in Australia after the ferry flight from Italy.

I am unaware of any flight test data or any justification for the Italian certification of the Autopilot/Electric trim system being sub- mitted to the RAI for this certification. (None was produced during legal discovery for the litigation by Partenavia to me and this was the process where Partenavia were legally required to produce all documents that we had requested.) Italian certification of the Autopilot/ Electric trim system would have been a prerequisite for testing to obtain American S.T.C. approval of this modification. I suspect that Edo-Aire were probably mislead into a false sense of security when conducting the flight tests for the STC issue as the aircraft had already obtained Italian certification. Partenavia may have lead Edo-aire into believing that aft C of G may have been the critical condition to be tested as it appears that this is the only condition that results appear to be satisfactory can obtained. Edo-aire document A75-66SW-DAS is incomplete, inadequate, superficial and misleading for the following reasons:

1; The section of the FAA Flight Test Report Guide Form 8110- 18(6.75) dated June 1975 on pages 69 and 70 referring to Electric Trim System including flight tests have not been reported on.

2; The only flight tests conducted at forward C of G position were function tests only

3; Autopilot malfunction and trim runaway tests were all con- ducted at aft C of G position only (This is not a normal operating condition for the P68B aircraft as even at all up weight the C of G position is normally towards the forward limit. VH-PNW was oper- ating at a weight only 57 kg below the maximum allowable operating weight and at a C of G position only six percent aft of the forward position of the total allowable on the night of the accident.
4; Trim runaway tests were not conducted hands free but “Stick force observations were made without allowing an aircraft or air- speed change to occur”
5; Trim runaway tests were not conducted in takeoff or climb configurations
6; Trim runaway tests were not conducted to determine if a temporary force of 50 pounds (22.65kg) on the elevator control was exceeded when corrective action is not initiated until the mal- function is detected by the pilot for the following time delays and conditions of flight:

Takeoff, climb, approach & landing 2 seconds Cruise 4 seconds

7; The most critical weight and C of G condition was not deter- mined and used for trim runaway tests. However the FAA- STC No SA 3067 SW-D was issued by Edo-aire on the 15-9-75. The Australian Dept. then approved the Autopilot / Electric trim system modification to the P68B for use in Australia even though they did not then or even now receive any flight test data from Partenavia to justify this Australian certification as required by ANO 101-22-7.3(6) They do not even have a copy of the S.T.C. The Dept. did not require Partenavia to submit any evidence “relating to the design to which the application relates including evidence of the effect of the design on safety of an aircraft” as
required by A.N.R. 40 ( 1 ) ( 2 ) The Dept. had previously recognized that the possibilities of problems occurring with aircraft designed and manufactured in counties other than the USA or the UK as they had included in ANO 101-22.1.2 “The Director-General may specify additional design stand- ards, documents and other evidence for aircraft types other than those designed in the United Stares of America or the United Kingdom.” I have not been able to discover any such additional require- ments being made for the certification of the P68B or its modification by installing the Autopilot / Electric trim system. In fact when one departmental officer suggested additional flight tests for the first of type certification, he was informed that under no circumstances would this be required (copy of departmental memo held) nor was any additional requirement made for the certification of the Autopilot / Electric trim system. In fact the reverse is the case as the Autopilot /Electric trim system was certified with the requirements being less than that required by the statuary standards. So the Autopilot /Electric trim system was certified in Australia. Partenavia produced flight tests numbered BM82 and BM83. These tests are dated 28-4-76 and are similar in nature to Edo-Aire flight tests. BM 82 and BM 83 and Edo-Aire document A75-66SW-DAS are all documents applicable to the Autopilot / Electric system installation certification none of which are in possession of the department. During April 1976 Forrestair took delivery of VH PNW. This aircraft Partenavia claim and the wreckage reconstruction would support this claim, was fitted with trim tab travel range number two of 28° This TTTR not certified in Australia and the change was not noticed during the certification process by the department and nor was it noted during subsequent maintenance by Forrestair or Phil White (Aircraft Maintenance Engineer). The only certification details of this change to TTTR 2 is included in. FAA types certifi- cate Data Sheet A31EU Revision 3 dated 23/11/76 more than six months after installation in VH-PNW. No justification have been discovered to myself or to the depart- ment and for this modification. A further modification of the trim tab travel range (TTTR number three) was approved by the R.A.I. on the 16th of the first 1978 in R.A.I. type certification data sheet SO/A151 revision five. This reduced trim tab travel range to 24° Again this modification has no design justification or flight tests discovered by Partenavia to myself, nor were any submitted to the Department Partenavia were either unaware, and, are unable or unwilling to notify certification authorities of changes to the P68 b design status and obtaining approval before incorporation into production aircraft. These modifications to the Trim Tab Travel range from 36° to 28° indicate that Partenavia were aware that a problems existed in the trim system Perhaps the events of the 10th of July 78, may have been averted at the modifications to 24° total travel had been incorporated into Australian aircraft as this reduced the nose-down trim capability by 54% from a total excess on over 140% to only 86% of excess capabilities. After the crash of VH-PNW on the 10th July 1978, Partenavia issued Service Bulletin 41 during October 1978, which changed trim tab travel range (TTTR number four) to 14° and again Partenavia have not discovered to me any design justification or flight tests to support this modification. Neither have they provided any design justification or flight tests to the Department The departments CAA report M131-515-4, I submit is the only fight test report that is available even though it would not produced until early 1989, that one is able to establish the actual trim tab travel required for the Partenavia. Even though its purpose was to determine the P 68.B’s compliance with F.A.A.23-689 (f) In doing this the Department has established the trim tab travel requirements for the P68B. By logical conversion as detailed in TTTR number 5, it can be determined that only 7 ½ degrees of total trim travel is required for the aircrafts safe operation.


MTF AB

[6317alan]

Part2 Sorry The Drawing is missing but would not transfer!




trim tab travel range number one 0 degrees + / – 1 degree Down To 16 degrees + / – 1 degree UP

This was the only range that was approved and certified in Australia for all P68B aircraft from the first of type certification on 23/1/75 until the mandatory modification incorporated in Partenavia Service Bulletin 41 in October 1978. This range is shown on the Trim Tab Travel Ranges drawing Page 118 coloured RED This travel range has an excess nose down trim capability of 18.5 degrees or 246 % excess capability. This travel range has an excess nose up trim capability of 10 degrees or 135 % excess capability. This excess capability has been calculated over that shown in Trim Tab Travel Range number 5 No design justification for this Trim Tab Travel Range has been discovered to A Baskett by the Department or Partenavia.

trim tab travel range number two 20 Degrees + / – 1 Degree Down - To 8 Degrees + / – 1degree Up

This range is shown on the Trim Tab Travel Ranges drawing as being coloured YELLOW.

This is the range that was approved and certified by the F.A.A Type Certificate Data Sheet A31EU Revision 3 dated 23/11/76. This range was not approved in Australia. This is the range that Partenavia claim was fitted to VH-PNW.



This appears to be the range fitted to VH-PNW as far as can be determined by wreckage reconstruction. This travel range has an excess nose down capability of 10.5 or 140% excess capability This excess capability has been calculated over that required in Trim tab travel range Number 5 No design justification for this trim tab travel range has been discovered to A Baskett by the Dept, or Partenavia

trim tab travel range number 3 20 Degrees +/- 1 degree To 4degrees +/- 1 degree Down

This range is shown on the Trim Tab Travel Range drawing as being coloured BLUE This is the range that was approved and certified by the R.A.I. Type Certificate Data Sheet SO/A151 Revision 5 dated 16/1/78 This Range was not approved in Australia This travel range has an excess nose down trim capability of 6.5 degrees or 86% excess capability This travel range has an excess nose up trim capability of 10 degrees or 135% excess capability. This excess capability has been calculated over that required in Trim tab travel range Number 5 No design justification for this trim travel range has been dis- covered to A Baskett by the Dept. or by Patenavia.

trim tab travel range number Four 1 degree Down To 15 degrees Down

This range is shown on the Trim Travel Range drawing as being



My Partenavia Report

coloured ORANGE This is the range that has been approved by the requirements to incorporate Partenavia Service Bulletin 41 in October 1978 This range is now approved in Australia This travel range has an excess nose down trim capability of 1.5 degrees or 22% excess capability. This travel range has an excess nose up capability of 5 degrees or 66% excess capability. This excess capability has been calculated over that required in trim tab travel range Number 5 No design justification for this trim travel range has been dis- covered to A Baskett by the Dept, or by Partenavia.

trim tab travel range number Five 2.5 degrees Down To 10 degrees Down This range is shown on the Trim Tab Travel Ranges drawing as being coloured GREEN This is the range discovered to A Baskett by the Dept. in C.A.A. document M-141-515-4 dated 17/2/89. This range is NOT approved in Australia. This travel range was established by flight test procedures to confirm compliance with F.A. R. 23-689(f) by a correctly rigged P68B aircraft at both forward and aft loading conditions, in so doing the total trim tab travel range required was also established for the Partenavia P68B (Note ) The method of determining the angular travel – was by dividing the 14degrees of travel of a correctly rigged aircraft by the number of divisions of travel indicated by the trim indica- tor i.e. 8.5 degrees. Therefore 1 division of trim indicator equals 1.65 degrees of trim tab travel. It is assumed linier along the trim indicator scale.




The M-131-515-4 document is the only document available that A Baskett has been able to discover that has any creditability to establish the actual trim tab travel requirement for the Partenavia P68B Aircraft.

Special Investigation Report 79-1

This Accident Investigation Report prepared by the Dept while appearing to be extensive and detailed in its investigation of this accident is in fact deficient in its pursuit of the subject matter to its logical extension of the ramifications of the total assessment of all the facts. The Dept have touched on the matter of pilot strength when they investigated control system failure caused by pilot input loads but chose to not detail in a similar manner the requirements of FAR 23-143(c) which limit the force required to be exerted by a pilot on a temporary basis not to exceed 75 pounds This report also omits to detail any reference to the fact that the position of the trim tab actuator was in a position that indicated that the trim tab travel was other than that certified in Australia This report omits to admit to the fact that the Dept failed to obtain flight test reports as required by ANO 101-22 prior to certi- fying the Autopilot/Electric Trim system. This report omits to detail that the Trim Tab Travel Range was excessive to that required to comply with FAR23-689(f) which establishes total trim capacity required for an aircraft. This report fails totally to address the fact that the Electric Trim System was never flight tested correctly as required. This report by not completely investigating all aspects of the Electric Trim System was able to minimize the design and certification deficiencies to enable the claim of pilot error to be raised by stating




“However, the more likely explanation is that the command trim switch was activated unknowingly.” This cannot be supported by any supported by any evidence as the coroner found at the inquest. The CAUSE as listed in this report is incorrect and misleading and would be more accurate if listed similar to the following.-

Cause The cause of the accident was that the aircraft became grossly out of trim at a height which did not permit time for the crew to affect recovery. The trim system design allowed control forces to be generated that exceeded pilot control force limits to be exceeded by a substantial amount. The manner in which the out of trim condition occurred has not been determined and the pos- sibility of a trim system malfunction cannot be eliminated.




All this was only achieved after many numerous legal orders were obtained as the Department did everything they could to stall and delay proceedings. I think their tactic was to maximize the delaying tactics hoping that I would tire of the whole process and just go away. I had to get a court order to get them to let me get copies All the documents were laid out on a conference table in a boardroom in no logical order. I then had to identify the relevant documents that I required to be copied. It ended up taking a full days work to sort out. In the end we ended up accepting an offer as I had been made aware that if I didn’t, Legal Aide would withdraw their support and I would be on my own from a financial point of view if I didn’t accept what was on offer. So reluctantly I accepted and at the end

[john_tullamarine]

FYI, the previous hyperlink now works.