- Author
- Steve Chaplin
- Subjects
- Naval Aviation, Aviation
- Tags
- None noted.
- RAN Ships
- None noted.
- Publication
- March 2023 edition of the Naval Historical Review (all rights reserved)
By Steve Chaplin
In this article the author continues the history of Skywest Aviation which appeared in the December 2022 edition of this magazine.
The Australian designed and manufactured Nomad aircraft suffered appallingly via the media, both in Australia and overseas, and was maliciously yoked with the nickname `The Widow Maker’ from the number of fatalities and incidents reported. Sadly, and again the media (specifically, journalists with very limited or no knowledge of this aircraft at all), made some very defamatory judgements regarding the actual incidents with the aircraft, which are covered in this article.
In the early 1960s the Government Aircraft Facility (GAF) in Melbourne, Australia initiated a program to design, construct, test and place into service an aircraft suitable for military and commercial use; by 1969 the design concept had changed to a twin-engine light passenger aircraft powered by turbine engines. Federal Government approval for construction of two flying prototypes and a static test airframe was announced in January 1970.
During the design of the aircraft, a decision on the type of engine to be fitted narrowed to a particular turbine engine and speculation suggests the designers were investigating 2 x Pratt & Whitney (P & W) turbo-prop engines. Apparently, these engines didn’t eventuate. Rumour has it that at the critical decision time into selecting these particular engines, the Pratt & Whitney workers were involved in an industrial strike with management and no assurances could be presented as to when production would recommence.
Finally, on the heels of intense research and lengthy discussion, the Nomad was powered by a pair of Allison 250B17B/C turboprop engines, capable of generating up to 400 hp (300 kW) each and Australia held in storage a significant number of these engines from the Iroquois helicopters used during our involvement in the Vietnam War.
GAF’s design team, although reportedly having been initially hesitant about applying a new engine to a new airframe, initially praised the engine’s behaviour upon the prototypes. After a detailed assessment and analysis, the Allison turbine was considered powerful enough and was of the appropriate size and weight to fit onto both the N22 and the N24 Nomad.
The first prototype N22 Nomad (VH-SUP) flew at Avalon airfield, Victoria on 23 July 1971 with test pilot Stuart Pearce at the controls. The aircraft had Short Take-Off & Landing (STOL) capability with full-span flaps for small/rough airfield operations. The name Nomad was adopted and the second prototype (VH-SUR) was flown to the United Kingdom for the 1972 Farnborough Air Show.
Manufacturing and Production
Production at GAF’s Melbourne factory commenced in 1972 with the first production aircraft flying in October 1974. In August 1976, the prototype N24 Nomad (VH-SUZ) crashed at Avalon killing both pilot and observer.
Despite numerous public announcements and rumours of large overseas sales orders over ten years, just 170 military and commercial Nomads were built before production ceased in 1984.
The N22B was a short-fuselage civilian version and the N24A was a lengthened fuselage civilian aircraft.
Specifications
| N22 Nomad | N24 Nomad | |
| Passengers: | 12 | 16 |
| Wingspan: | 16.46 m (54 ft) | 16.46 m (54 ft) |
| Length: | 12.57 m (41 ft 2 in) | 14.35 m (47 ft 1 in) |
| Height: | 5.52 m (18 ft 1 ½ in) | 5.52 m (18 ft 1 ½ in) |
| Wing area: | 30.2 m² (324 sq ft) | 30.2 m² (324 sq ft) |
| Cruising speed: | 311 km/h (168 knots) | 311 km/h (168 knots) |
| Max cruising speed @ 1,525 m (5,000 ft): | 313 km/h (170 knots) | 313 km/h (170 knots) |
| Max cruising speed @ 1,525 m (5,000 ft) @ 4,083 kg (9,000 lb): | 320 km/h (173 knots) | 320 km/h (173 knots) |
| Cruising speed @ 75% Power: | 282 km/h (153 knots) | 282 km/h (153 knots) |
| Initial rate of climb: | 444 m/min (1460 ft/min) | 390 m/min (1280 ft/min) |
| Minimum control speed: | 122 km/h (66 knots) | 123.2 km/h (66.5 knots) |
| Single engine ceiling: | Non-Given | 3,110 m (10,200 ft) |
| Service ceiling: | 7,165 m (23,500 ft) | 7,165 m (23,500 ft) |
| Take off distance over 50 ft. obstacle: | 320 m (1050 ft) | 521 m (1710 ft) |
| Landing distance over 50 ft. obstacle | 226 m (740 ft) | 421 m (1380 ft) |
| Range w/reserves @ 3,050 m (10,000 ft) | 1,482 km (920 miles) | 1,545 km (964 miles) |
| Range with 1,633 kg (3,600 lb) payload: | Not provided | 1,352 km (730 miles) |
| Range with 1,000 kg (2,200 lb) payload: | Not provided | 1,448 km (900 miles) |
| Endurance – search mission @ 5,000 ft: | @ 259 km/h (140 knots) 8 hrs | @ 259 km/h (140 knots) 8 hrs |
| Fuel capacity: | 1018 litres (2244 lbs) | 1,018 litres (2244 lbs) |
| Empty weight: | 2170 kg (4783 lb) | 2,449 kg (5399 lb) |
| Baggage capacity: | 58 cu. ft | 70 cu.ft |
| Loaded weight (MTOW): | 3,855 kg (8500 lb) | 4264 kg (9400 lb) |
| Engine: | Allison 250B17BC | Allison 250B17BC |
| Power: | 400-420 hp (300-310 kW) | 400-420 hp (300-310 kW) |
| Propeller: | Hartzell 3-blade, 90.63 in. (2302 mm) diam. | Hartzell 3-blade, 90.63 in. (2302 mm) diam. |
Specialised civilian and military models included the Missionmaster Military version of the N22B, a N22B Floatmaster floatplane developed in the USA and the Searchmaster coastal patrol version with Bendix or Litton radar units. A Medicmaster air ambulance model was used by the Royal Flying Doctor Service and the Northern Territory Aerial Medical Service.
N22B – Army Nomad
In 1987 it was announced that the remaining unsold Nomads would be supplied to the RAAF and the Army (who had been operating the type as the Missionmaster). An apparent tailplane failure caused the death of pilot FLTLT Glenn Donovan flying a modified N24 Nomad near Gawler, SA in March 1990. All Army Nomads were grounded for a period and were subsequently withdrawn from service in 1995. The RAAF had already withdrawn their Nomad aircraft from use in 1993.
Most of these ex-ADF aircraft were sold to the Indonesian Naval Air Arm. Despite the problems experienced inAustralia, the Nomad was sold to overseas military and civilian customers and many of these aircraft remained successfully operational.
As the successor to GAF, Boeing Australia held the type certificate for the Nomad and in June 2008 it was announced that the type certificate along with design and development rights had been sold to Gippsland Aeronautics at Morwell, Victoria. In 2010 Gippsland Aeronautics intended to manufacture a modified version of the Nomads using Rolls-Royce 250-17F2 engines. Production of around 200 aircraft was believed to be the target for manufacture. As at July 2022, there has been no evidence of production of these aircraft.
Skywest’s Nomads
Skywest became heir to their Nomads through their participation in the purchase of H.C. Sleigh Aviation in the early 1980s. Three of the aircraft acquired were the N22 Searchmaster Nomads attached to the Customs contract and two additional N24A Nomads (VH-FHS and VH-FHR) were used in Regular Public Transport (RPT) around Perth and other regional destinations.
In the latter part of the 1980s, six more N24 Medicmaster aircraft were added with the establishment of the Northern Territory Aerial Medical Services contract (NTAMS) in Darwin, N.T. This made Skywest the largest commercial operator of Nomads in Australia, with a total of nine N22/N24 Nomads.
VH-FHS and VH-FHR were utilised in the RPT services to Rottnest Island, Bunbury and other regional centres. They suffered badly from engine complications and tailplane difficulties and were most unpopular with the travelling public. These aircraft leaked so badly in winter that passengers were provided with umbrellas to prevent being thoroughly drenched from leaks in the cabin overheads. Several passenger windows actually detached from their frames and fell into the cabin during flight. The two aircraft were not kept in that particular role for long – approximately two years. These were very early days of Nomad operations and classified as ‘teething’ issues.
Pilot Training
Generally the flight training for the Aero Medical pilots was assigned to the Deputy Chief Pilot. Our theatre of operations involved questionable airfields/landing zones, so the training of our pilots was exacting to the nth degree – specifically, night flying into unlit airfields.
Approximately 37 nm to the south west of Darwin was a fishing village on a small island named Dum in Mirrie. The island was leased by a family (parents and two sons) and operated quite successfully in the tourism market as it was in a region renowned for tremendous fishing adventures.
Skywest had a very harmonious relationship with the operation. On the island was a runway which had been constructed by the family (heavy equipment had been previously barged in) and was assessed by the Civil Aviation Safety Authority (CASA) as an approved light aircraft airfield. The runway length was approximately 1200 metres (3937 ft). Given its location from Darwin, away from the city lights, Dum in Mirrie was the ideal training facility in which to maintain ‘night landing’ currency, especially the NTAMS pilots.
Usually four or five pilots, along with the Deputy Chief Pilot, would relocate to the island just prior to sunset and then with the assistance of the owners, set up paraffin lamps alongside the runway in preparation for their night flying exercises. The other interesting pickle in the barrel was that the Deputy Chief Pilot also selected night training flights on moonless nights, making it pretty black all round. And so, after an early evening meal and with the sun well and truly down, the night flying began in earnest. These night flying sorties brought to the fore the most demanding and precise flight proficiencies expected of our pilots and this was acknowledged with all of the flight sisters/nurses praising the professionalism of these amazing people. Even under the calmest conditions, landing an aircraft at night onto a strip of dirt only identified by paraffin lamps is most certainly not for the faint hearted. Each pilot carried out three take offs and landings on each assessment of their night flying competence.
The N24 Nomad aircraft excelled in these Short Take Off and Landing (STOL) flights and were well suited for their role in Medivacs. I have to say emphatically that our pilots trained under some of the best and highly qualified flight instructors – bearing in mind, at that time, the Skywest pilots were part of the Ansett empire and all pilots held an Ansett Seniority Number, giving them a pathway into commercial airline operations. Annually, Skywest would ‘lose’ approximately 10% of their pilots into the Ansett off-take.
Whenever I flew on an Ansett flight, heard the announcement of the flight crew and realised that I knew them I relaxed, knowing the levels of training and experience they had undergone on their pathway to airline pilot standards.
Australian Customs Service
From as early as 1983, there were three N22B Searchmaster Nomads assigned to the Australian Customs Contract, operated and crewed from Townsville (Qld.), Darwin (NT) and Port Hedland (WA). These particular aircraft were fitted with the Bendix RDR 1400 Surface Search Radar (Range – 275 nm approx.) which enhanced the surveillance capabilities of the aircraft, especially when the aircraft was engaged in drug smuggling and people smuggling operations.
Throughout the 1980s and up to the withdrawal of the aircraft from operational service (mid 1990s) the aircraft operated very much independent from the Coastwatch style of operations and concentrated on a more covert and stealth strategy optimised from the use of the surface search radar. Australian Customs assigned a significant number of flights to the location and tracking of suspicious vessels arriving within Australia’s borders and believed to be engaged in drug smuggling actions.
As an indicator as to how successful the Nomad Customs aircraft were in tracking and identifying suspected traffickers of illegal substances and goods into Australia and resulting in the arrest and prosecution of the offenders, this following incident occurred in the late 1980s.
Whilst the Chief Pilot (yes, he got to work at the coal face too) was performing a pre-flight inspection on the Cairns based N22A Nomad, he reached up into the jet intake to ensure all was OK and discovered a fifty cent coin positioned at the mouth of the engine intakes, ready to be sucked into the engine after start up.
Had this not been discovered, it was very probable significant and expensive damage to the engine would have occurred, resulting in the aircraft being taken off-line until such time as the engine was replaced. It was clearly placed there by person/s associated with the drug trade who were attempting to remove a surveillance aircraft that perhaps had been monitoring their illegal activities.
The probability of the coin being ingested at take-off was negligible, given this threat would have been discovered during engine run ups prior to take off, so it was fortuitous in that aspect that no loss of life would have occurred. It also demonstrated the thoroughness of pre-flight procedures incorporated into the pilots’ training.
Together with their sister aircraft attached in the Aerial Medical Role, the Customs Nomads operated effectively, efficiently and profitably throughout their periods of service with Skywest Aviation. Testament to the scheduled and unscheduled aircraft maintenance procedures, Skywest had an unblemished safety record in their operation of these aircraft, and did not experience any major air incidents throughout their term of service. Adherence to stipulated and stringent maintenance constraints supported the safety records.
The Damning Statistics
As mentioned earlier, the GAF Nomads suffered horrendously at the hands of the uneducated and ill-informed media – as the saying goes with all journalists ‘why stuff up a good story with the facts’! With extensive research, the statistics speak for themselves and again, could raise significant argument or questions regarding the overall operations and maintenance of these particular aircraft.
In surveying the statistics of the GAF Nomad incidents, the three main categories are as follows:
Structural failures,
Engine failures, and
Pilot error.
The most damning indicator is that the aircraft suffered nine reported engine failures, resulting in 55 fatalities, compared to only three reported structural failures and four fatalities, with the biggest indictment being of pilot error with twelve incidents resulting in 37 fatalities.
Engine Failure: Strangely, the Allison 250B17B/C engine was a very successful helicopter engine, but very problematic in fixed wing applications – nobody could ever explain why. One probable theory was that the engines were working much harder in fixed wing fitment than on the Bell 206 Jet Ranger helicopter. The particular type and model Allison engine has been utilised in 16 other fixed wing configurations and as a result of its popularity and performance, nearly 30,000 Model 250 engines have been produced, of which approximately 16,000 remain in service today, making the Model 250 one of the highest-selling engines manufactured.
This raises the question/argument, was this type/model turbine engine ever inverted in other fixed wing aircraft – unquestionably, mounting a turbine engine which had been designed for use in a helicopter raises concerns about its ability on a fixed wing aircraft, especially when it had to be mounted upside down to mount onto the wing spar.
I know from personal experience, that if the engine/s had not been started for a period of three days, it used to dump all the engine oil out onto the tarmac. Skywest Engineers later discovered a problem within the gearbox system which caused the gearbox oil to be ‘syphoned’ out. By the installation of a secondary filter system between the compressor and the gearbox, the fault was rectified. Many complaints from airport reporting officers were received that our Nomads were pissing on the tarmac – again! To overcome this problem, the engineers or a qualified Nomad pilot had to conduct engine run ups every few days to settle everything down again.
Engine Maintenance: Maintenance of the Allison 250B17BC turbine engine, like all aircraft gas turbine engines, requires extreme expertise. Scrutinising a majority of engine failure locations outside of Australia and as to ‘who’ was operating and supporting these aircraft, could give rise to questioning as to – were these individual engineers performing maintenance on the engines wholly certified and experienced on this engine ‘type’ and how much ‘engineering’ hands on proficiency did the engineers actually have to perform this required maintenance! Also, was finance/cost a significant factor attributed to the engine maintenance requirement? Availability of funds for maintenance is one known area where short cuts can and have been known to occur and the end result is typically catastrophic, particularly if non-genuine spare parts are incorporated into extremely significant sections of the engine.
Pilot Error: In depth investigation of these reports identified that a major proportion of the pilot error incidents on the Nomads was because the pilot-in-command of the aircraft at the time of the incident had very limited ‘time on type’ flight time on the aircraft. What is of significance though is that the Incident Reports identifying pilot error, more often than not do not provide in-depth details of the pilot’s state of mind, what event was occurring at the time, external events removing the pilot’s concentration from critical procedures etc. and it is these factors which are not correctly reported on by the media.
For those of us who have been employed in either/both civil or military aviation throughout our careers, I believe we all become infuriated at the media reporting of any aircraft incident – particularly when fatalities are involved, that they (the media) assert ‘improper’ theories on causes of the incident and ‘probabilities’ of what ‘perhaps’ should have been done to prevent the incident, all without knowing the facts! Aircraft accident investigators who have the unenviable task of determining the cause of incidents will examine hundreds (perhaps thousands) of hours of evidence to discover the cause, whether mechanical, weather or human error, of any accident and recommending future action to avoid a similar outcome.
As in all significant aircraft incidents ‘pilot error’ is always examined by the authorities, along with a multitude of other probabilities. An approach we all must agree on is the question of why or what caused a pilot to actually do what he/she did to cause the catastrophe. The only one who can answer that question is the pilot and sadly, in a majority of those incidents, the fatalities included the cockpit crew.
Some Engineering Post-mortem Items:
A couple of interesting phases related to the Allison 250B17B/C turbine engine utilised on the Nomad aircraft was this: the engines, when installed and operated with rotary wing aircraft, needed only to operate between 65% – 75% power (torque), whereas when installed and operated on the Nomad, both engines were required to operate at around 100% capacity at all times. This is a somewhat interesting comparison.
In the early days of Skywest’s operation of the Nomads, the engines were regularly removed for over-haul and sent to the aircraft engineering contractor for Allison in Melbourne, where this procedure was carried out.
It was discovered that the engines were not being test run immediately after overhaul; instead, the engines were shipped straight back to Darwin and when the engine/s were returned into service, pilots and engineers detected these engines were either not developing full power and/or losing power quite quickly. Once these shortfalls were identified, the overhaul facility mandated a compulsory test running of the engines after overhaul. After this situation was addressed, no further complications emerged.