Collision on the ground involving a Piper PA-28, VH-TXH and a Cessna 172, VH-EUU, at Moorabbin Airport, Victoria, on 11 April 2015

What happened

On 11 April 2015, the student pilot of a Piper PA-28 aircraft, registered VH-TXH (TXH), prepared to conduct a solo, local flight, from Moorabbin Airport, Victoria. The flight was to be the pilot’s second solo to the training area, where he was to practice simulated forced landings. The pilot inspected the aircraft, including checking the oil quantity and colour. He noted that the dipstick indicated 5.5 L of oil and the oil appeared to be of a golden colour. After completing the pre-flight checks, the pilot of TXH taxied the aircraft to the run-up bay and performed engine run-ups. He noted that all indications were normal and within the required performance limits.

At 11:29:06 Eastern Standard Time (EST), the pilot made a radio call to the Moorabbin surface movement controller (SMC) on the Ground frequency, advising that he was conducting a solo flight to the training area and requested a departure from runway 35 Right (35R). The SMC cleared TXH to taxi via taxiway A for a departure from runway 35R. TXH then taxied to the holding point for runway 35R, and, at 11:36:37, the pilot of TXH contacted the aerodrome controller – east (ADC1) on the Tower East frequency. He reported ready for take-off, and ADC1 cleared TXH for take-off.

At 11:37:08, the pilot of a Cessna 172 aircraft, registered VH-EUU (EUU), contacted the SMC and requested a clearance to taxi for a local private flight, with three passengers on board. The SMC cleared EUU to taxi to runway 35R via taxiway A, and the pilot commenced taxiing.

The pilot of TXH reported that the take-off run was normal, with the engine indications in the normal range. After rotation, when about 150 ft above ground level (AGL), the engine began to run roughly. The pilot lowered the aircraft nose slightly and within 2-3 seconds, the engine regained full power and the aircraft continued to climb. When approaching 500 ft AGL, the engine again ran roughly and partially lost power. The pilot suspected a fuel issue to be the cause of the rough running, and, as the fuel pump was still on, changed the selected fuel tank. The engine returned to producing full power and the pilot initiated a right climbing turn, leaving the fuel pump switched on. As the aircraft climbed, the engine lost power again.

At 11:37:58, the pilot advised ADC1 that he had a ‘spluttering engine’ and requested a return to land. ADC1 had observed TXH in the initial climb and noted that it did not appear to be climbing out normally and was then quite low, at an estimated 300 ft AGL. ADC1 initially responded that TXH was number one for runway 35R and then offered runways 22 or 31 if required. The pilot responded that he would use runway 22 (Figure 1).

ADC1 gave TXH priority to land over all other aircraft, advised the SMC of an aircraft with engine trouble, requested runway 22, and coordinated with the SMC for release of runway 22 (see section: Air traffic control). The SMC checked the crossing taxiways, helicopter traffic and for any works in progress that may have conflicted with the use of runway 22, then handed ADC1 the green runway strip for runway 22. ADC1 then placed the strip in the runway bay on the console. ADC1 also coordinated with the aerodrome controller – west (ADC2), who instructed a couple of aircraft in the circuit for runway 35 Left (35L) to go-around to ensure they remained clear of the crossing runway. ADC1 instructed the pilots of two aircraft that were in the circuit for runway 35R to go-around and another to conduct a full stop landing. The SMC reported then focusing on checking the runways and taxiways crossing runway 22. Taxiway A did not cross runway 22, and as the SMC remained seated, was unable to see EUU on taxiway A as it was obstructed by the tower console.

Figure 1: Moorabbin Airport, aircraft tracks and collision point

Source: Google earth annotated by the ATSB

At 11:39:06, ADC1 cleared TXH to land on runway 22. The pilot of TXH conducted a tight right turn towards runway 22 and as he was concerned about clearing the buildings on the approach to runway 22, he did not select any flap. After passing over the buildings, the pilot reduced the power to idle. He reported that the aircraft touched down about one third of the way along runway 22. ADC1 observed that TXH appeared to land about half way along the runway and did not decelerate normally after touching down. The SMC observed that TXH appeared very low on final approach to runway 22 and crossed the threshold travelling very fast. The ADC1 stated to the SMC and ADC2 controllers ‘he’s landed long’ and ‘gee he’s quick’.

The pilot of TXH assessed that he was not going to be able to stop the aircraft prior to the end of the sealed runway, but that there was a suitable grassed overshoot area beyond it, and maintained the aircraft on the runway centreline. ADC2 was standing up, and sighted EUU on taxiway A. ADC2 alerted the SMC to the Cessna (EUU) on taxiway A. ADC1 observed that EUU was then still north of the extended centreline of runway 22 on taxiway A.

As TXH approached the end of runway 22, the pilot of TXH sighted EUU taxiing on taxiway A to his right, and was unsure whether it was going to stop or not. He veered TXH to the right in an attempt to pass behind EUU and avoid a collision. At 11:39:25, the SMC directed EUU to ‘hold position, STOP, STOP’. The pilot of EUU braked immediately and as his body moved forward in response to the aircraft braking, he sighted TXH in his left peripheral vision. The pilot of TXH saw EUU brake suddenly.

The pilot of EUU assessed that if he stopped there, TXH would collide squarely with EUU, so he released the brakes and progressed forwards. The left wing of TXH then struck the tail of EUU and spun EEU around through about 180°. TXH continued veering to the right for about 20 m further before coming to rest on a grassed area (Figure 2).

Figure 2: Accident site

Source: Airport Operator

The pilot of TXH observed fuel spilling from the ruptured fuel tank and immediately exited the aircraft and reported that he was not injured. The pilot of EUU reported that he momentarily lost consciousness at the time of the collision, but came to within seconds. He then observed fuel leaking, and although feeling disoriented, he conducted a normal aircraft shut down, including switching off the aircraft electrics and fuel. He and the passengers disembarked and were treated for minor injuries. Both aircraft sustained substantial damage (Figures 3 and 4).

Figure 3: Damage to VH-TXH

Source: Airport operator

Figure 4: Damage to VH-EUU

Source: Airport Operator

Pilot comments

The pilot of TXH provided the following comments:

• He did not declare an emergency as he assessed that he would be able to land the aircraft safely. He remained calm and focused on his approach to, and landing on, runway 22.
• He wanted to ensure that if the engine failed completely he would have sufficient height to clear the buildings in the approach path of runway 22.
• He did not have sufficient altitude to continue a circuit and land on 35R.
• He was unable to stop the aircraft before the end of runway 22, but if there had not been an aircraft on the taxiway, he would have been able to stop safely in the overshoot area.

The pilot of EUU commented that as he was on Ground frequency and the pilot of TXH was on Tower frequency, he was not aware of TXH until he sighted it immediately prior to the collision. He reported that if he had been directed to stop earlier, it may have averted the collision.

Controller comments

The ADC1 controller provided the following comments:

• The ADC1 offered the pilot of TXH the choice of runways to land on, but did not know what was achievable for the pilot or aircraft.
• The ADC1 and ADC2 controllers both stood up when the pilot of TXH reported engine trouble.
• The incident was a good example of how quickly things happen; about 90 seconds after an aircraft took off it was back on the ground and at least two aircraft had to be sent around in the interim.

The SMC reported checking the works strip under the runway designators in the console. The SMC scanned the eastern helicopter area, checked the taxiways that crossed runway 22 – ‘F’, ‘B’ and ‘C’ for any aircraft waiting to taxi, and did not see anything that may pose a risk to an aircraft landing on runway 22. Taxiway A was not a crossing taxiway for runway 22. The SMC reported that these scans were performed multiple times after the pilot of TXH advised of engine trouble. The SMC further commented that if TXH had maintained the runway centreline, the aircraft would not have collided.

Moorabbin Airport and weather conditions

Runway 22 at Moorabbin was 571 m in length, runway 35R was 1335 m. The wind was from 030° at about 7 kt, resulting in a tailwind on runway 22.

Air traffic control (ATC)

There were three ATC positions active at the time; a combined surface movement controller / coordinator position (SMC), an aerodrome controller – east (ADC1), and an aerodrome controller – west (ADC2). The three controllers were seated in the tower in that order from north to south facing towards the east, and were the only people in the control tower at the time. Runways 35L and 35R were the runways in use prior to the pilot of TXH reporting engine trouble. A runway in use is a runway under the control of an aerodrome controller. All runways are considered ‘active’ and a clearance is required to cross or enter any runway. The runways other than those in use, were held by the SMC. The ADC1 therefore required the release of runway 22 from the SMC prior to clearing TXH to land. The controller places the runway strips of the runways for which they hold responsibility, in the runway bay of the console.

Engineering inspection

A post-accident inspection of the engine of TXH found a small quantity of oil on the cylinders and some fouling of the spark plugs which may have led to the rough running.

Safety message

The ATSB publication Avoidable Accidents No. 3 – Managing partial power loss after take-off in single-engine aircraft, found causes of partial power loss after take-off include fuel starvation, spark plug fouling, carburettor icing and pre-ignition conditions. A pre-flight safety brief that considers actions to take following a partial power loss after take-off, gives pilots a much better chance of maintaining control of the aircraft and of responding immediately. Such actions include landing immediately within the aerodrome, landing beyond the aerodrome, and conducting a turn back towards the aerodrome.

Aviation Short Investigations Bulletin - Issue 41