Safety Matters and Safety Briefs are based on the AAIB Bulletin UK Airprox Board reports, with additional material from the US National Transportation Safety Board
Results of choosing the wrong runway; and not knowing who’s in control
Wrong runway stall/spin
Aircraft Type: Rans S6-ESD (Modified) Coyote II Date & Time: 30 May 2016 at 1557 Commander’s Flying Experience: NPPL, 185 hours, eight on type Last 90 days: 13 hours Last 28 days: 10 hours The aircraft was on a flight to Shifnal, where Rwy 36 was in use, although the ‘T’ in the signals square indicated that Rwy 28 was the active. When the aircraft turned onto the right-hand downwind leg for Rwy 28 witnesses noticed that it was lower and closer to the airfield than normal for that circuit and appeared to be following the railway line which runs just north of the airfield. It was then seen to turn right towards the final approach leg for Rwy 28, flew through its extended centreline, rolled wings level and headed towards the airfield, although noticeably south of the normal final approach path and near to a local noise-sensitive area.
The aircraft then turned onto an easterly heading, the turn described by witnesses as “quite steep” and at a low speed. It rolled abruptly in a manner suggesting a wing-drop stall, from which it recovered, then at low height banked left, appeared to enter a spin and descended out of view. A witness who was not at the airfield had a clear view of the final part of the aircraft’s descent and said that it was pitched nose-down approximately 80° and turned through at least 300°.
The Coyote II crashed in a gently sloping barley field south-east of the Rwy 28 threshold, in an upright but steep nose-down attitude. Pilot and passenger had been fatally injured. One propeller blade had broken off on impact and fragmented into multiple pieces. The other blade remained attached and intact. Neither blade displayed substantial evidence of leading-edge damage or chordwise scuffing, indicating lack of rotation, or rotation at low power, at impact.
Examination of the wreckage at the AAIB’S Farnborough facility confirmed
that the operating system for the primary flying controls was intact prior to the accident, although substantial disruption occurred during the impact. It was not possible to ascertain the trim state of the aircraft due to disruption of the elevator control and bungee trim system.
The AAIB report concludes: ‘The pilot had recently bought the aircraft and had accrued about eight hours on the type, flying this aircraft. It was reported that, during two flights with the previous owner, he (the previous owner) had taken control from the pilot when he became concerned about the aircraft’s speed.
‘The pilot had visited Shifnal previously, possibly when Rwy 28 was in use, but it was not established how he had flown the circuit on those occasions… In the absence of a PPR briefing, the pilot probably did not know that Rwy 36 was in use. The prevailing conditions, as indicated by the windsock, favoured Rwy 36, but the signals square indicated that Rwy 28 was active. On arrival, the aircraft flew just west of the airfield, on a southerly track, and entered the circuit through the south-west gate (which positioned it) on the dead side of the Rwy 28 circuit. As witnessed, it then flew a downwind leg for Rwy 28, closer to the runway than normal, and, concurrently, the pilot made a ‘downwind’ radio transmission.
‘It is not known why the aircraft flew the downwind leg closer to the airfield than seemed normal. The radio transmission, which the pilot made downwind, did not include any mention of a problem. The pilot may have been following the railway line, instead of the A464 road, as the line feature to use to remain south of the (noise-sensitive) avoid area. This would explain the proximity of the aircraft’s downwind track to the airfield and, consequently, the reason for the aircraft’s low height. At the conclusion of the base turn, the aircraft was displaced south of Runway 28’s extended centreline, which might be expected given the northerly wind and the proximity of the downwind leg to the airfield.
‘It then broke off the approach, did not go around, and turned on to an easterly track, away from the airfield, possibly to reposition for the final approach to Rwy 28. The wing-drop observed by witnesses was indicative of flight at an angle of attack which was close to the stall. An initial recovery appeared to have been achieved but, at a height of approximately 290ft agl, the aircraft seemed to enter a spin from which it did not recover. There was some evidence
from the engineering investigation, to suggest that spin recovery had been initiated, as there were no rotational marks on the ground or in the crop at the accident site and the aircraft had struck the surface in a steep nose-down attitude. On impact, the engine was operating at low, or no, power. Although there were no conclusive findings from the engine examination, the possibility of an engine stoppage or power loss, due to carburettor icing or other reasons, could not be ruled out.’
Recognising the possibility of future confusion, the flying club at Shifnal has removed the landing T and signals square, to prevent incorrect signals being displayed.
An AAIB analysis of accidents to Uk-registered Rans S6s (all variants) since 1999 revealed that fifteen had involved stalling and/or spinning, resulting in four fatalities, six serious injuries (one to a member of the public) and five minor injuries. As a result of the rate of stall/spin accidents the Light Aircraft Association has undertaken to conduct a safety review encompassing the following aspects:
Complete a review of accident data with the type to date, including consideration of the aircraft configuration, weights and centre of gravity positions, mission and pilot profiles of those involved, including a comparison with the accident data for similar types of microlight;
Carry out flight tests on at least two representative examples to investigate possible handling, performance or other factors that might contribute to an elevated accident rate, including: longitudinal stability; ability to trim in pitch; longitudinal and lateral/directional trim changes with changes in power and configuration (i.e. flap position);
directional stability and control, including contributing effects of adverse yaw with aileron input, and any contributing ergonomic aspects;
pre-stall warning and stall characteristics;
ease of operation of controls;
adequacy of low-speed stall recovery/ climb performance at different weights and centre of gravity positions;
behaviour in a simulated engine failure;
and instrumentation, particularly the adequacy of indication of airspeed and slip.
The results of the safety review will be communicated to all Rans S6 pilots within the LAA membership, and on completion of the flight tests the Association will also produce a series of Pilot’s Notes tailored to each airframe/ engine combination on the UK S6 fleet.
Who’s in command here?
Aircraft Type: Robin DR400/180 Regent Date & Time: 7 December 2016 at 1327 Commander’s Flying Experience: PPL, 863 hours, 728 on type Last 90 days: 21 hours Last 28 days: 0 hours Six days after a minor eye operation to remove a cataract the pilot asked a flying instructor to act as his ‘safety pilot’ and occupy the right seat of the
dual-controlled aircraft for a local flight from Rochester.
The pilot believed his eyesight had fully recovered from surgery, but as it was also six weeks since his previous flight he thought having the instructor with him was a sensible precaution. However, the role of ‘safety pilot’ was not discussed before the flight and the instructor did not regard himself as pilot-in-command.
Rochester has two parallel runways positioned close together, Rwy 20L, which is the relief runway, and Rwy 20R, the main runway. Before departure, the instructor met the duty Flight Information Service Officer and was told that Rwy 20L would be used for takeoff and Rwy 20R for landing. Circuits were not permitted because of the condition of the grass, but practice forced landings (PFLS) were allowed. According to the pilot, he was not informed that Rwy 20R was to be used for landing.
The first PFL approach was towards Rwy 20L, but the aircraft was too high so the pilot went around before starting a second approach to the same runway. In the latter stages, at the suggestion of the instructor, the pilot ‘warmed the engine’ by advancing the throttle for a short time. He did not recall being advised to go-around, and by the time the Robin was about 15ft above the ground he believed he could have landed on Rwy 20L, albeit that the aircraft was pointing left of the runway because he “overcompensated for the drift”.
He later stated that he was about to apply power and right rudder when, without warning, his inputs on the control column were overridden and the aircraft turned 60º right. He initially thought there was a malfunction of the flying controls but then the instructor declared “20 Main” and the pilot realised that the instructor was handling and had rolled the aircraft right towards Rwy 20R. The pilot believed the aircraft was now close to stalling, because power had not been increased, but he managed to regain control and land on Rwy 20R. After taxiing to the apron he learned that the Robin’s right mainwheel had struck an abbreviated precision approach path indicator (APAPI) in the Rwy 20L undershoot
After the accident the pilot realised that he and the instructor should have briefed carefully before the flight and discussed what they understood by the term ‘safety pilot’ and who was to be PIC. Although after the flight the pilot signed in the aircraft technical log’s ‘captain’ column, he thought he was flying as Pilot-in-command Under Supervision (PICUS) and expected the ‘safety pilot’ to offer verbal input during the flight. He also thought the instructor, acting as ‘safety pilot’, could take control if safety was compromised and assumed that he would announce such action in the conventional way, stating “I have control”.
The instructor, who had logged 10,309 hours total flying experience, mostly instructional, with 5,010 hours on type, said that when he agreed to act as ‘safety pilot’ he considered it a check flight rather than an instructional flight, because he knew the pilot was licensed and his currency permitted him to fly with passengers.
During the first PFL the instructor saw that the aircraft was too high and the pilot sensibly executed a go-around. On the second approach he saw the aircraft deviate below the optimum glidepath so, at approximately 400ft, he suggested that the pilot apply a “clearing burst of power for five seconds”, thinking that the engine would be warmed and the additional power would allow the aircraft to regain the glidepath, but the pilot did not apply power for as long as suggested. His recollection was that because the aircraft was still low, he then directed the pilot to go-around, but he did not react.
At a late stage in the approach the instructor recognised that the aircraft was “in a stalling configuration, low and slow” and was tracking towards a rough area to the left of Rwy 20L, a situation he regarded as dangerous, so he tried to take control by turning the aircraft right towards Rwy 20R. However, he was prevented from doing this because the pilot did not relinquish control. Nevertheless, he believed his unannounced intervention was necessary because the pilot had not been flying in a “satisfactory manner”. He could not explain why he did not announce taking or handing back control, or why he did not initiate a go-around.
In retrospect, the instructor realised that a thorough pre-flight briefing ought to have been held and that he should have enquired carefully about the pilot’s medical situation. When he checked the relevant regulations he (like the pilot) was not aware that ‘safety pilot’ is not a recognised role in normal operations. Although he felt his intervention prevented a more serious accident from occurring, to refresh his skills and to learn from the event the instructor carried out subsequent training with a flight examiner.
The AAIB comments: ‘Prior to the flight the pilot and instructor had not appropriately briefed and agreed their roles and procedures. Both thought that the instructor could act as “safety pilot”, providing verbal advice from the right seat, while being available to take control if the pilot became incapacitated. However, the role of “safety pilot” was not applicable because the pilot’s medical certificate was not endorsed “OSL” and, because the instructor did not sign for the aircraft as PIC, his role was that of a passenger and he should not have tried to perform instructional duties.
‘Although not causal to the accident, the pilot had an operation to remove a cataract from his right eye. Following the procedure he should have consulted with his AME as it was a surgical operation and also to ensure that the treatment he had received did not interfere with flight safety’.
Following an investigation, safety action was taken at Rochester to ensure pilots are told which runway is in use when they call on the radio prior to arrival.
Wrong runway and wrong attitude caused a similar Coyote II to stall and spin
Failure of the left leg actuator seal resulted in a false gear down and locked indicator
Failure to agree the role of ‘safety pilot’ contributed to confusion about who was in control of the Robin aircraft similar to this one