The crew were carrying out rappelling recurrency training at the time of the accident. During the first of several planned descents down the rope, from 70 ft, the rescue crewman misjudged his speed and landed heavily, resulting in a fracture of his right leg.

The speed during descent is normally controlled by the degree of braking applied to the rope by one hand. The braking required is judged on 'feel' through the glove. The rescue crewman was wearing two pairs of gloves as the pair he normally wore were slightly frayed. He had previously only worn a single pair during rappelling activities. It is probable that the extra pair of gloves altered the 'feel' causing the crewman to misjudge his descent rate.

The crew were all endorsed for rappelling activities, a pre-flight briefing had been completed, and activities were being conducted in accordance with the operations manual. However, the rescue crewman's rappelling currency had lapsed.

Safety Action

The operator has introduced a flying safety instruction requiring crew, who's currency in rappelling has lapsed, to complete at least three descents from a suitable static platform prior to helicopter operations. In addition, the first rappel from the helicopter will be completed from 30 ft instead of 70 ft.

The operator is also researching the use of mechanical braking devices as an alternative to the 'feel' system.

The purpose of the flight was to aero tow a glider from a paddock where it had made an out landing. Prior to take-off the pilot measured the paddock twice by pacing. The paddock was wedge shaped with powerlines running along the two longer boundaries. There was also a powerline spanning the paddock towards the narrow end of the wedge. Despite walking under this powerline while pacing the paddock, the pilot did not see it.

Take-off was into the northwest which provided the longest take-off run and was also into a 5-7 kt wind. After take-off the pilot held the tug down to gain speed. He then saw the powerline but too late to avoid it. After impact with the powerline the tug hit the ground and was substantially damaged.

The pilot said that in the take-off direction, the powerline was below the horizon against a background of hills which made it almost impossible to see.

VH-IGJ departed Canberra CTA on the Canberra Yass track 20 miles from Canberra and cruising at 4500 ft. Approximately five minutes later VH-IJA departed Canberra CTA on the same track, 20 miles from Canberra and cruising at 6000 ft. At that time the controller noted a radar return two miles ahead of IJA, orbiting on the Canberra Yass track, also at 6000 ft but climbing.

Flight Service was advised so as traffic could be passed to IJA and Flight Service was also asked to contact IGJ. The pilot of IGJ reported to Flight Service at 6700 ft. The base of CTA was 6000 ft at that position. The radar return was identified as IGJ. Shortly afterwards IGJ left CTA no descent.

Factors

The pilot of VH-IGJ initiated a climb into controlled airspace without a clearance.

The Cherokee departed from runway 14 to track to Flat Top Island, 4 NM east of Mackay, to carry out Airwork. Soon after, a Brasilia reported ready to take-off from the same runway, with the intention of tracking to Rockhampton via the 131 VOR radial. The aerodrome controller cleared the Brasilia to take-off after observing the Cherokee appeared to be established on track to Flat Top Island.

The pilot of the Brasilia reported that as he turned left to intercept the 131 VOR radial, he noticed the VOR had apparently failed and attempted to resolve the problem. Soon after, the copilot reported another aircraft immediately ahead. The pilot saw a Cherokee about 200 metres away at the same altitude, but slightly to the left, and passing from left to right. He took immediate evasive action by turning left to pass behind the other aircraft.

The investigation established that the instructor in the Cherokee had been concentrating on the instructional sequence and had not continued on track to Flat Top Island as cleared. The Cherokee had been subsequently turned onto a south-westerly heading, which conflicted with the flight path of the departing Brasilia.

History of the flight

Prior to landing West Sale, the crew were advised by air traffic control that the weather conditions at Latrobe

Valley, their next landing point after West Sale, were wind 270/5, cloud seven oktas at 800 ft and visibility 5000 m. 

Considering these conditions, the pilot in command elected to fly from West Sale to Latrobe Valley, a distance of 25 NM, at 4000 ft and make an NDB approach at Latrobe Valley. Weather conditions enroute were considered marginal for a VFR flight below the cloud base.  The minimum descent altitude for the NDB approach at Latrobe Valley is 1000 ft so the crew were aware they may not get into Latrobe Valley.

When they taxied for departure at West Sale, the crew were advised by air traffic control that another aircraft had flown to Latrobe Valley visually below 1000 feet above ground level and made a successful approach and landing, about 40 minutes previously.  On the basis of this information, the pilot in command decided to follow the same procedure.  An alternative course of action, in the event that visual reference was lost, was planned and briefed prior to departure.  The aircraft then departed and according to the crew, proceeded visually below the cloud at a reduced airspeed of 170 to 180kt, at 500 to 700 feet above ground level with a flight visibility of about 5000 metres.

Approaching Latrobe Valley all appropriate checks were completed.  Calculated landing weight was 6400 kg which equated to a target threshold speed (Vref), pilot in command could not recall any Vref minus calls. The captain did not respond to Vref minus calls by application of power.

Touchdown was heavy and both crew members agreed there had been no landing flare.  The co-pilot sensed an increased sink rate shortly before touchdown but did not note the vertical speed indication.  The crew found no damage to the aircraft during a post flight inspection.  However, the day after the occurrence, minor damage consistent with a heavy landing was discovered.  An inspection of the runway threshold, after the occurrence, revealed that the aircraft had touched down just prior to the threshold and had hit and broken two frangible runway end lights.

The investigation

As part of the investigation, the flight data recorder was read out.  This revealed that at touchdown, airspeed had reduced to below Vref and sink rate was high (approx:102 kt/1000 ft/min+).  Runway 03/21 at Latrobe Valley is 1430 metres long, is narrow (an 18 metre wide sealed section), has no touchdown zone markings or approach guidance lighting (e.g. TVASIS).  Visibility was reported by the crew to be about 5000 metres at the airfield and deteriorating.  Light rain was falling.  The pilot in command did not turn on the windscreen wipers because on long final approach, speed was in excess of the windscreen wiper limit speed and later on final he was reluctant to divert his attention from flying the approach to the wiper control switch.

The crew did not activate the runway lighting which may have assisted with approach angle guidance.  The pilot in command stated that he was aiming to touch down just past the piano keys (the threshold) due to the runway being wet, narrow and having a downslope (0.4% down to the southwest).

The pilot in command acknowledged that he clearly misjudged the approach in that the aircraft touched down before he had initiated a landing flare.  It is possible that there may have been a visual illusion created by the combination of a narrow runway, reduced visibility and rain on the windscreen.

Safety action

As a result of its investigation the company has instituted the following measures:

1. The Metro Operations Manuals are being amended to reflect the requirement to call excessive sink rate on final approach.
2. The operator has distributed an aircrew circular describing techniques which assist in overcoming visual illusions associated with approaches to narrow runways, particularly in reduced visibility conditions.
3. Runway lights are to be activated on narrow runways to assist in assessing approach angle.
4. All flight crew members are to complete crew resource management courses.

FACTUAL INFORMATION

A BAe146 (VH-NJN) was maintaining flight level (FL) 280 on a flight from Cairns, Qld to Ayers Rock, NT.  The crew reported over Alice Springs at 1236 CST with an estimate for Ayers Rock of 1312.

A second BAe146 (VH-JJW) departed Alice Springs at 1237 for Ayers Rock and climbed to FL240.

Both aircraft were under the control of Melbourne air traffic control (ATC) sector 5 which was staffed by a trainee under the supervision of a team leader. The aircraft were subject to procedural control procedures.

The trainee controller coordinated the two aircraft positions with flight service, giving the estimated times of arrival (ETA) at Ayers Rock as 1312 for NJN, and 1318 for JJW.   An error was made in the time of arrival for JJW in that the trainee incorrectly added the flight plan time intervals.  The correct estimate was 1316.  This error was not detected by the team leader.

When both aircraft were on the control frequency, the trainee checked their respective DME distances, this resulted in NJN being 22 NM ahead of JJW. As the aircraft were of the same type, a suitable standard (15 NM) had been established to allow the descent of NJN through the level of JJW.

At 1253, the crew of NJN requested descent.  This was approved by Melbourne control and the aircraft commenced descent at 1255.  At 1256, the crew established contact with flight service and advised their ETA as 1311.

At 1259, the crew of JJW requested descent.  This was approved by Melbourne control and descent was commenced at 1302.  At 1303, the crew contacted flight service and advised their ETA as 1312.  The flight service officer then passed traffic information on three aircraft, including NJN, to the crew of JJW.

The flight service officer also passed traffic information on JJW to the crew of NJN who then transferred to the Mandatory Broadcast Zone (MBZ) frequency.

Shortly after, the crew of JJW also changed to the MBZ frequency and commenced a DME check with the crew of NJN.  This resulted in the aircraft being 12 NM apart while JJW was passing FL180. Based on this information, the crew believed that NJN passed through their flight level in controlled airspace with only 12 - 14 NM separation and therefore a breakdown in separation had occurred.

As the aircraft approached Ayers Rock, in the MBZ, a pilot initiated distance check revealed that the aircraft had reduced the separation to 4 NM.  Both aircraft landed without further incident.

ANALYSIS

Air Traffic Control

The two minute error made by the trainee in the ETA for JJW at Ayers Rock was not considered to be a factor in this occurrence because the flight service officer passed traffic information based on the pilot reports not the ATC estimates and the DME check was independent of the ETA.

The controller established a correct separation standard (15 DME) for aircraft of the same type and issued control instructions appropriate to the circumstances.  It is probable that the correct distance for this standard was maintained throughout the period of flight within controlled airspace.

The flight progress strips that the controllers had for reference did not differentiate between the various series of BAe146 aircraft.  Additionally, the Manual of Air Traffic Services only published some of the various profile speeds for the BAe146 series of aircraft and these were displayed in the radar control section, not specifically in the procedural control sections. Flight Service

The flight service officer provided traffic information in a correct manner appropriate to the circumstances.

Aircrews

Both crews acted in accordance with ATC instructions and operated their aircraft within company profiles.

Flight Plans

The flight plan held by the crew of JJW varied to that held by ATC in that the ETA Ayers Rock on the crew's plan was 1312 and on the ATC plan was 1316. The reason for this discrepancy was that ATC took the overall block time provided by the flight plan and had their computer calculate the ETA at each reporting point based on the various distances from one point to the next.  As the company provided a two minute manoeuvring time at the departure and destination aerodromes, a four minute difference existed between the times provided to ATC in the flight plan and the time the pilot held in the cockpit.  The pilot based his reporting calculations on the time of departure and had, therefore, already accounted for the two minute manoeuvre prior to advising his actual departure time to ATC. ATC then added the computer generated time intervals to this reported time of departure and the erroneous situation was complete.

Aircraft Performance

ATC reference data for the BAe146 aircraft indicated that there was a similarity of performance between the operating profiles of the various series of BAe146 aircraft operated by all companies.  This was not the case, as the operating profiles indicated that a difference of up to .08 Mach can exist while two aircraft are on descent.

This performance differential could lead to a degradation in certain separation standards such as the 15 DME standard used in this case.

Additionally, the reference material was only contained in the radar sections of the Manual of Air Traffic Services.

SIGNIFICANT FACTOR

The air traffic controllers had insufficient information to indicate that significant closing between aircraft may occur.

SAFETY ACTION

As a result of the investigation the following action was taken:

Local ATS management introduced an amendment to the Manual of Air Traffic Services (MATS) Local Instructions which specifies the full range of performance options for BAe146 series aircraft.

Airservices Australia has undertaken to amend MATS to ensure that the information on BAe146 aircraft is adequately displayed for controller reference.

Airservices Australia and the operating company of JJW are consulting over the format for flight plan submission so that both parties understand the requirements and operating methods of the other.  This process should ensure that controllers and aircrew have the same initial information on which to base their operational requirements.

Due to poor lift conditions the pilot was forced to make an outlanding. He selected what appeared to be a suitable paddock and noted there was a powerline running parallel to the selected landing direction. Late on final approach, the glider hit another powerline that the pilot had not seen. This line was a three-wire spur line crossing the landing path at 90 degrees and originating from an area of trees.

Significant Factors

The following factors were considered relevant to the development of the accident:

1 The pilot had to make an outlanding due to poor lift conditions.

2 The pilot did not see the powerline before his aircraft collided with it.

The foreign registered Boeing 747SP was on a flight from Melbourne to Sydney and was under the control of Sydney Approach (APP). Whilst being radar vectored for an extended downwind leg to runway 16R, the aircraft was issued with a clearance to descend to 5,000 ft, which was read back by the flight radio operator. The controller then instructed the crew to change radio frequency, and re-confirmed the cleared altitude as 5,000 ft. The weather at Sydney was CAVOK.

The aircraft was subsequently observed on radar to descend to 2,600 ft, while on the downwind leg. Several attempts by the controller to contact the aircraft were unsuccessful. At about this time, the altitude readout of the aircraft's transponder ceased to be visible on the radar screen, with only primary returns being received.

About 2.5 minutes later, the Approach controller re-established radio contact and instructed the aircraft to climb to 3,000 ft, at which point the altitude readout re-appeared on the radar screen.  The aircraft was then processed for a landing without further incident. The Approach controller subsequently reported that he had re-confirmed the instruction to descend to 5,000 ft because he was unsure the crew had understood the clearance.

For international operations the airline concerned delegates the responsibility for all English language radio transmissions to a flight radio operator. The radio operator on this flight had accumulated some 25 years’ experience, including several flights into Sydney over the last seven years. When the flight radio operator read back "five thousand" on the second occasion, the controller was satisfied that the clearance had been understood. Recorded radio communications confirmed that the controller had used correct radio phraseology and that the flight radio operator had correctly read back the descent clearance.

It was later found that the flight radio operator believed the instruction had been to descend to "two five thousand", which he initially interpreted as 25,000 ft, although the aircraft had already descended to 6,000 ft. He chose not to question the clearance as he rationalised the controller had meant 2,500 ft.  He called out "two thousand five hundred” to the non-handling pilot, who entered these numbers in the altitude select window on the mode control panel.  When the controller issued the frequency change, and confirmed the descent clearance, the flight radio operator believed that 5,000 ft was the altitude at or below which the frequency change was to be made.  All crew members on the flight deck were listening on headphones at the time of the occurrence and said they were somewhat confused by the clearance instruction but chose not to query it.

SAFETY ACTION

As a result of the investigation, the Bureau issued the following Interim Recommendation to Airservices Australia on 17 July 1996:

"IR960050

The Bureau of Air Safety Investigation recommends that Airservices Australia amend radiotelephony phraseology in the Australian Manual of Air Traffic Services and Aeronautical Information Publication to eliminate the possibilities for misunderstanding in the use of the word "to" in climb/descent instructions." On 27 August 1996, Airservices Australia responded as follows:

"Reference is made to BASI Air Safety Interim Recommendation No. IR960050 relating to the use of the word "to" in climb/descent instructions.

This matter has been widely debated in a number of workshops held with the aviation industry, Defence and CASA during the review of phraseologies used in Australia. In the interests of international harmonisation and in concert with our agreed position with Australian aviation interests, Airservices will continue to align with ICAO and retain the use of the word "to" with level change instructions. Use of the word "to" in this context is consistent with ICAO Doc 4444, PANS RAC, Part IX   Phraseologies Section 3, paragraph 3.1 .2.

Given the need for clarity in communications and to reinforce the point made by ICAO at Part IX, paragraph

2.1 " ATS personnel and other ground personnel will be expected to use appropriate subsidiary phraseologies which should be as clear and concise as possible and designed to avoid possible confusion by those persons using a language other than one of their national languages", the Bureau's Interim Recommendation has been forwarded to our ATS Training Section for further action.

With regard to the publication of instrument approaches on charts to assist VFR pilots, as discussed in IR 950206, I understand that CASA is in the process of reviewing this recommendation. In addition, publication of instrument approaches on charts is currently under discussion in the Airspace 2000 proposals on pages 36 and 68 of the document titled "Airspace 2000 - A Plan for the Future Management of Australian Airspace"."

The response has been classified as OPEN.

Approaching home base, towards the end of a charter flight, the pilot became concerned about a low fuel quantity indication on the fuel gauge, so he advised his company by radio that he was landing in a paddock about 7 nm south-south-east of Moorabbin. He also requested that fuel be brought to him.

After landing and shutting down the engine, the pilot realised that the nearest access to the aircraft by road was blocked by a canal and a fence. He therefore decided to reposition the aircraft to facilitate refuelling. After starting the engine and having hover-taxied a short distance with an estimated 20 kt tailwind and at about 10 ft above the ground, the helicopter's engine flamed out due to fuel exhaustion. The aircraft touched down, heels of the landing skids first, on uneven terrain. The main rotor severed the tail boom, and the helicopter rolled over.

According to the pilot, the fuel gauge registered 45 US gallons when he commenced the charter. He believed this was sufficient fuel to complete the flight using a fuel burn off rate of 25 US gallons per hour. However, since leaving base, the engine had operated for an estimated one hour and 50 minutes, including the time spent at ground idle. Unusable fuel is 10 pounds (1.7 US gallons). Only a very small amount of fuel was found in the tank after the accident.

No fault with the engine or the airframe has been reported to have contributed to the accident. Both of the electric fuel boost pumps were serviceable and operating at the time. The aircraft was not equipped with the optional, low fuel warning light system.

Significant Factors

The following factors are considered relevant to the development of the accident:

1. The pilot did not exercise sound fuel management procedures.

Approaching Tintinara on a cross-country flight, lift conditions deteriorated, necessitating an outlanding. The pilot chose what appeared to be a suitable paddock and made an approach and landing. During the landing roll, as the glider came up over a rise in the terrain, a fence appeared across the landing path. The glider could not be manoeuvred to avoid the fence and a collision ensued. The pilot had not seen the fence during the visual inspection of the intended landing area from the air.