Ombudsman’s Report into RAAF Nomad Crash

• The RAAF’s investigation (into the crash and its causes) was conducted well and identified many deficiencies.
• The RAAF had in fact not gone far enough to attribute individual responsibility for deficiencies found and gave inadequate consideration to the question of disciplinary action.
• The RAAF did not attempt any ‘cover up’ of any issues relating to or flowing from the crash of A18-401.

However, the Ombudsman, in investigating the matter, also disclosed major deficiencies on the part of ASTA and the CAA as outlined below.

The History Of Nomad A18-401 And The Circumstances Of The Crash

Nomad A18-401 was manufactured by GAF in 1982 and registered as a development aircraft under the CAA permit to fly system. This allows an aircraft to be fitted with prototype equipment, whilst still remaining under a measure of external supervision by the CAA. Between 1982 and 1987 the aircraft flew approximately 345 hours on development work, following which its tailplane was lent to another GAF aircraft where the tailplane flew a further 70 hours. The tailplane was subsequently refitted to A18-401 at the start of the latter’s first major service in September 1988.

In December 1987 the aircraft was sold to the RAAF but remained at Avalon, being subsequently loaned back to ASTA on August 1 1988. The RAAF finally took physical possession of the aircraft in August 1989 and flew it to the Air Force Research and Development Unit (ARDU) in South Australia. The aircraft was flown for a further 8.7 hours (including the three hour delivery flight). It subsequently suffered a catastrophic in-flight tailplane failure on March 12 1990 during normal flight, causing the death of its pilot, Flt/Lt Donovan.

The Nomad Tailplane Design Saga

The Ombudsman’s investigation established that as far back as 1981 there had been concerns within GAF about the adequacy of the tailplane in terms of its ability to withstand abnormal flight loads and wind gusts on the ground. As a consequence, following a report into an investigation into tailplane torque-box beam cracking, a service letter was released calling for a visual inspection of the torque-box beam every 100 hours. Put simply, the Nomad’s all moving tailplane by its very nature, if unrestrained, is particularly susceptible to wind gusts which cause it to bang against its stops, which in turn leads to cracking. The original design was not capable of coping with the stresses and strains imposed on it under these circumstances and several fixes were developed, none of them proving successful.

The CAA (then Department of Aviation) was aware of the problem and was pressing GAF for an adequate resolution as far back as 1983. Up until 1989 it was believed that the cracking was the result of overload damage and the inspection regime for the aircraft was developed on that basis. However, the CAA subsequently received a report from a civil operator indicating that cracking was occurring as the result of normal flight operations. This raised concerns within the CAA to the extent that the following specific questions were put to ASTA:

• Is the cracking solely caused by an overload condition?
• Does the cracking reduce the ability of the structure to withstand design loads?
• Will the cracking continue to propagate, if so, at what size will it become critical? and over what period of hours/cycles?
• What action if any is proposed by ASTA?

Two weeks later, in the absence of any response, the CAA, obviously concerned, again wrote to ASTA as it had become apparent that the problem was common to all operators and an Airworthiness Directive (AD) was being considered. No answers were ever provided by ASTA, and unfortunately no follow up action was taken by the CAA to resolve the matter during the subsequent nine month period leading up to the crash of A18-401.

The Ombudsman in considering this aspect of her investigation found that the CAA, in failing to pursue ASTA for an adequate response, itself failed adequately to discharge its obligations to the aviation industry and the public. Had the CAA obtained the necessary answers it could have addressed the question of the need for an AD, which in turn might have prevented the crash of A18-401. The Ombudsman did, however, accept the explanation that extensive cuts to personnel in the Structures and Fatigue areas of the CAA at that time precluded staff from pursuing all safety related matters. In considering ASTA’s failure to respond to the CAA queries, the Ombudsman found that despite some discussions between the respective regional staffs, ASTA’s inaction represented a glaring administrative failure.

Ground Running Of A18-401 And Its Significance

The Loan agreement between the RAAF and ASTA called for monthly reports of the hours flown and the operational use of the aircraft. ASTA correctly interpreted this to include ground running but failed to forward all reports to the RAAF. In addition ground running was not accurately recorded, but the subsequent RAAF Board of Inquiry (BOI) determined that the tailplane in question (SIN 140) had undergone at least 177 hours of ground running during trial while fitted to A18-401 and to the other GAF aircraft. The BOI noted that at least 38 hours of ground running were conducted during the period the aircraft was on loan from the RAAF.

The lengthy ground running carried out on A18-401 far exceeded that which would be experienced by an aircraft in normal use. The BOI in fact determined that expressed as a percentage of hours flown, at 40% it far exceeded the norm of 2-5%. The BOI also determined that there were difficulties in ground running Nomad aircraft in that considerable effort was required to hold the control column steady in order to minimise tailplane movement. The degree of elasticity in the control circuit meant that even with the control column fully forward, the tailplane continued to oscillate, constantly banging against its travel stops. This was a likely cause of faster than normal growth in tailplane cracking in A18-401. The failure by ASTA personnel to appreciate the effects of extensive ground running was the next link in the accident chain.

Acquisition Of The Aircraft And Acceptance By The RAAF

One of the lesser links in the chain of events leading up to the crash, and perhaps only identifiable with hindsight, was the fact that the aircraft were acquired by the RAAF as a result of the GAF being transformed into a separate corporate identity (ASTA). The normal processes of aircraft acquisition through the development of a requirement, and the subsequent careful structuring of a project directive to implement the acquisition did not take place. Instead, the Defence Minister agreed that a number of unsold and used Nomads would be transferred to the Department of Defence. A project directive (Project 5998) was, however, developed to cover the acquisition, initially being handled by the Tactical Fighter Project Office (TFPO), but subsequently passed to the Utility Helicopter Project Office (UHPO).

The RAAF BOI found major deficiencies in the conduct of Project 5998, essentially stemming from confusion in the RAAF command structure as to what was required to bring the aircraft into the RAAF maintenance system. A significant outcome of this confusion was the fact that the two ARDU Nomads were never subject to a Statement of Work (SOW) to establish a base line for their operational service with the RAAF. Although desirable, this was not done due to lack of available funds. In addition, ARDU decided not to undertake an acceptance servicing, although Headquarters Support Command Engineering Branch (HQSC) had recommended such action be taken. In the event the aircraft entered service with ARDU on the basis of the servicing it had received whilst with ASTA under CAA rules. Had a thorough survey of the aircraft been undertaken it is most likely that the dangerous state of the tailplane would have been discovered; another link in the accident chain.

RAAF Scheduled Servicing And The Detection Of Tailplane Cracking

The RAAF, in response to the GAF Service Letter referred to above, introduced an inspection regime into its system of regular servicing for the Nomad aircraft. This called for inspections at 125, 250 and 1750 hours, known as R1, R2, and R3 servicings. The RAAF also introduced two additional servicings, the first, the S8 service covered abnormal flight loads and wind gusts, and the second, the S17 service was an anti-deterioration service. The S17 service is calendar initiated.

During its investigation, the RAAF BOI firstly established that had an R1 due in August 1989 been carried out, the dangerous condition of the aircraft would have been found. It also established that although the S17 service had been noted in A18-401’s Daily Aircraft Log (EE511 form) as falling due on March 6 1990, it was decided by two ARDU Maintenance Section NCOs that the servicing did not apply to A18-401. Because it was decided that the S17 servicing did not apply, no entry in relation to that servicing was made in the form EE500 (Aircraft maintenance/pilot’s acceptance form). This denied the pilot, Flt/Lt Donovan the opportunity to decide for himself whether the aircraft was safe to fly and was the final fatal link which completed the accident chain.

The Question Of RAAF Responsibility And Disciplinary Action

The Deputy Ombudsman, in his Draft Report recommended that the conduct of certain RAAF members be re-examined for consideration of possible disciplinary action. The subsequent RAAF legal advice was that the basis for charges against five RAAF members existed at the time of the crash but that such action was now outside statutory time limits. The Ombudsman in her report states that she can see nothing further to be gained by pursuing the matter; however she notes that civil damages are being pursued in court by the family of Flt/Lt Donovan.

Recommendations In Relation To The Caa

The main recommendation in relation to the CAA is that the Safety Regulation and Standards Division be brought up to strength in order that it may properly discharge its function.

Recommendations In Relation To Asta

In addition to examining the issue of individual responsibility within its organisation, the Ombudsman recommends that ASTA examine its aircraft testing and maintenance procedures. The question of the stresses on Nomad aircraft of extensive ground running should also be the subject of additional research.

Comment

Clearly there was a massive breakdown right across the whole spectrum of Nomad operations which could have been detected and corrected at many points; in retrospect the accident chain was there for all to see. Again, when the orderly processes of Defence force equipment acquisition are not followed for whatever reason, political or otherwise, the opportunity for disaster to strike will be ever present. Finally, this is yet another accident, a measure of the responsibility for which should be sheeted home to those in the political arena responsible for the cost cutting measures inflicted on the CAA.