Safety Matters and Safety Briefs are based on the AAIB Bulletin, UK Airprox Board reports and additional material from the US National Transportation Safety Board
Two fatal accidents; deciding whether to go around again
Poor weather, fatal outcome
Aircraft Type: Rockwell Commander 114B Date & Time: 3 December 2015 Commander’s Flying Experience: PPL, in excess of 200 hours, at least 100 on type (the pilot’s log books were not recovered) Last 90 days: Unknown Last 28 days: Unknown The aircraft took off from Isle of Man (Ronaldsway) at 0836 on a private VFR flight to Blackpool. The Blackpool TAF predicted the lowest visibility around the aircraft’s time of arrival would be 1,400m in heavy rain, with broken cloud 300ft above the aerodrome. At 0851 the pilot established contact with the Blackpool Approach controller, who was providing a procedural service — Blackpool does not have radar. The subsequent R/T exchange went thus (Ba=blackpool Approach, C114=commander 114):
BA: “I’ll give you the full weather because it’s not very nice. Surface wind indicating zero niner zero degrees at four knots, visibility two thousand metres in slight rain and mist, cloud few at two hundred feet, scattered at one thousand six hundred feet, broken at three thousand six hundred feet, temperature plus eight.” C114: “Er, can I fly this… can I land in this?” BA: “That’s entirely up to you and your licence restrictions.”
C114: “Of course it’s up to me… Er, I can always divert back to the Isle of Man if it’s not suitable. Which runway is in use please?” BA: “Runway one zero in use.” C114: “Runway one zero. Er, if I can land, can I take it on a long final?”
BA: “You can make a straight-in approach for runway one zero.”
The aircraft tracked towards Blackpool, through a helicopter traffic zone around oil and gas rigs in Morecambe Bay, and exited the zone at 0858 at an altitude of 800ft and a groundspeed of around 115kt. It reached, and then tracked, the extended centreline of Rwy 10. At approximately 12nm from the aerodrome the aircraft descended to 700ft. At 0902 the pilot reported at ‘approximately ten miles’, and was instructed to report when he had the runway in sight. At 0904 he enquired again about the weather and was given ‘Current cloudbase is few at one thousand one hundred, but (indistinct word) is few lower at about two hundred,’ which he acknowledged.
When the Commander was 7nm from the aerodrome it descended to 500ft, and then at about 5nm to 400ft. Groundspeed reduced progressively to less than 60kt, and its track turned north-easterly at around 4nm, before turning again towards the runway centreline, now at 300ft. The final R/T exchange took place at 0907:
BA: “(Callsign) report visual with the aerodrome, the lights are on maximum.”
C114: “Er, wilco… I haven’t, haven’t got it in sight yet.”
The Commander’s lowest groundspeed shown on radar was 48kt, and the final radar return recorded at 0907 showed it at 200ft, descending, at 57kt. The R/T recording included two very brief sounds, one at 0908 and one at 0909, which could have been momentary transmissions from the aircraft. In the background of the first was a high-pitched tone, possibly the stall warner. At 0910 the controller asked the pilot to report his range from Blackpool, but received no reply, so he initiated search and rescue action. Several helicopters took part, and their pilots remarked upon the low cloud, poor visibility, and ‘fishbowl’ effect they encountered over the sea in the search area. One, who was a military fixed- and rotary-wing pilot, commented that it ‘was not a day to be out over the sea at low level… there was a significant opportunity for [the pilot] to have been disorientated.’
An SAR operation by the Maritime & Coastguard Agency (MCA) spotted a fuel or
light oil slick in the vicinity of the last known radar position of the aircraft, and several very small pieces of wreckage were also found. No other items were recovered until the following morning when a member of the public found a small shoulder bag containing various items including an instrument flying textbook which linked it to the pilot. MCA staff later recovered a set of plastic aircraft wheel chocks.
Several hours after the accident, conditions deteriorated into a prolonged period of very severe weather which prevented a further underwater search for wreckage until eleven days later, when a police maritime unit found an aircraft on the seabed. The very poor sub-sea visibility precluded positive identification or examination, but the location, description and colour scheme strongly suggested it was the Commander, lying inverted in one piece, with the fin and cabin area buried in soft sand, and landing gear extended.
A privately-funded salvage operation conducted almost three months after the accident could not be completed because the aircraft had become full of compacted sand and was firmly lodged within the sea bed, but it did recover the engine, propeller and part of the left wing, which were examined by the AAIB. The engine showed signs of impact with the sea and had been damaged by the salvage operation. All three propeller blades were bent and twisted and the spinner had been flattened. The distortion of the propeller blades indicated that the engine had been producing power when it came into contact with the sea. The flattening of the spinner suggested a steep angle of impact, but there was not enough evidence to determine whether the aircraft was upright or inverted.
The AAIB report concludes: ‘[Whilst] a technical fault or an external influence, such as a bird-strike, cannot be entirely discounted… the meteorological conditions were correctly forecast, and although it was not possible to establish what forecast information the pilot had gathered, his conversation with [another Ronaldsway pilot] indicated that he was aware of the possibility of inclement weather. Although he was not inexperienced, he held a PPL without any instrument flying qualification, which would have made a flight in the prevailing conditions challenging… The pilot’s enquiry to the Blackpool Approach controller, “Er, Can I fly this… can I land in this?” suggests that he was dubious about carrying on, and his remark that returning to Ronaldsway was an option suggests that he considered doing so. A prompt reversal of his course, back towards the better weather at Ronaldsway, might have prevented the accident.’
Unexplained microlight fatality
Aircraft Type: Dragon Chaser Date & Time: 31 October 2015 Commander’s Flying Experience: NPPL, 242 hours, 2 on type Last 90 days: 17 hours Last 28 days: 4 hours The pilot regularly flew flexwing microlights solo, and three-axis types under instruction. He had flown the flexwing Dragon Chaser on two previous occasions. The aircraft took off from Sywell Aerodrome in benign weather conditions with light winds, good visibility and no low cloud.
Nothing further is known until several witnesses saw the aircraft in flight close to the accident site. Though none had a lengthy uninterrupted view, their combined accounts provided an impression of the final minutes of the flight. One saw the aircraft flying ‘lower than aircraft usually do’, make a sharp left turn onto a south-westerly heading, and descend ‘quite steeply’ before it passed out of her view. A second reported that he first saw the aircraft in level flight at about 100ft agl before it gained a little height and then began to descend, turning to the left onto a more southerly track. The descent was at a constant angle for a period until, ‘at about the height of a house’, its descent steepened and the aircraft struck the ground hard. He recalled hearing nothing until the impact with the ground, which he heard quite clearly, which led him to believe that the engine either had not been running or had been running quietly.
The attention of a third witness was first drawn by the sound of the aircraft, which became quieter, probably abruptly, and the aircraft was descending quite steeply before it disappeared from sight behind a tree, after which she heard a ‘crunch’. A fourth saw the aircraft ‘coming down quite steeply’ before it hit the ground. It appeared to be under control and he thought the pilot might have been attempting to land. A fifth heard the ‘loud-ish noise’ of the aircraft and saw it ‘very low’ close to the accident site. He said that the engine ‘feathered’ as if the throttle had been closed and the aircraft then dropped, with the front wheel of the trike digging into the ground, after which the aircraft somersaulted and then came to rest. Two of the witnesses ran to the crashed aircraft and attempted to give first aid but the pilot had been fatally injured.
A post-mortem examination of the pilot revealed that he had died from chest injuries. No evidence of any medical condition likely to be incapacitating was found, and toxicological testing revealed nothing remarkable.
The aircraft crashed in a large field some 400m long and 100m wide, coming to rest at the top of a gently sloping knoll. There were several ground marks consistent with the nosewheel striking the ground heavily, after which the aircraft appeared to have performed a somersault, making two holes in the ground, first with the apex of the wing and then with the top of the mast, before it came to rest in an upright position.
The aircraft was inspected and no evidence of a pre-existing structural failure or control problem was found. The wreckage was taken to AAIB headquarters in Farnborough for a more detailed
examination during which the battens were removed from the wing and checked against the manufacturer’s full-scale drawing. Nothing significant was found. The engine was stripped by the UK distributor, which found no evidence of any mechanical failure or abnormal running of engine or gearbox. It was concluded that the engine was probably producing significant power on impact, because both propeller blades had broken.
The AAIB report concludes: ‘There was no evidence of the progress of the flight from takeoff until witnesses saw the aircraft close to the crash site. From the witnesses’ recollections, the aircraft appeared to be under control and under power before, from a low height, it entered a descent which steepened and ended with impact with the ground. The accounts of engine noise drawing attention to the aircraft suggest that the engine was running at least until a change in tone was heard; the aircraft was already at a low height when this occurred. The reason for this low height could not be determined; it may have been a consequence of a problem with the aircraft, or intentional on the part of the pilot, or because of some other factor.
Descriptions of the engine note changing or ceasing suggest the engine power may have reduced, either in response to pilot input or as a consequence of an engine problem. The combination of dew point and temperature indicate that conditions were on the border between those in which serious icing of the carburettor might occur at any power and moderate icing at cruise power. Serious icing might occur at descent power, but carburettor icing leaves no evidence and thus no conclusion could be reached in this regard.
‘The field in which the aircraft crashed was suitable for a landing, either preplanned or forced. Because the landowner’s permission had not been sought, an intentional landing seems unlikely. In either event, any landing could have been challenging because the approach would have been almost directly into a low, setting, sun, and on the knoll before a slightly-down-sloping surface. Although the post-mortem examination did not identify any evidence of incapacitation in flight, this possibility could not be ruled out.’
Unexplained power loss
Aircraft Type: Piper Saratoga II TC Date & Time: 12 April 2016 at 1300 Commander’s Flying Experience: CPL, 4,061 hours, 35 on type Last 90 days: 78 hours Last 28 days: 31 hours The aircraft was returning to Daedalus Airfield [formerly Lee-on-solent] from where the pilot had departed earlier. After levelling at 1,800ft amsl, he selected cruise power and turned off the electric fuel pump. Shortly afterwards, the engine began to run roughly, so he turned the pump back on and changed tanks, but these actions had no effect, nor did leaning the mixture then returning it to full rich.
As he was now halfway to his destination, the pilot decided to continue the flight, and joined downwind for Daedalus’s Rwy 23. No PAN call was transmitted, but when downwind the pilot saw a glider and tug aircraft operating on the airfield and made a radio call to announce his position. In response he was informed that the launch would be expedited but, on final at 300ft agl, the glider had yet to begin its takeoff roll, and the Saratoga’s pilot applied power to go-around. However, the engine did not respond and the aircraft was forced to land in a grass field short of the runway.
The aircraft sustained substantial damage. A total of fifty US gallons of fuel was found on board the aircraft and testing showed no water or other contaminants. The engine and ancillaries were removed and sent for overhaul, but, despite extensive examination, no fault was identified.
Latest Airprox reports
The Airprox Board reviewed twenty incidents in July 2016, of which nine were assessed as risk bearing, Categories A or B, five of which involved drones. The remaining four involved a Cessna 152 flying through the Chatteris DZ and into conflict with eight parachutists; a Chinook and a Ventus glider that came into proximity near Wantage due to late-/non-sightings; a Navajo and Mooney that came close in IMC without appropriate ATS; and an Extra conducting an overhead join at Peterborough-conington, as below.
The Board’s ‘Airprox of the Month’ was that involving the Extra pilot, who is registered as hard-of-hearing and had pre-notified Peterborough-conington that he would effectively be carrying out a radio-failure overhead join at a predetermined time. ‘Unfortunately, the message did not get through to the A/G operator and so there was a certain amount of confusion when the Extra pilot transmitted blind his intentions, which were unfortunately either stepped-on or distorted by interference of some sort,’ says the report. ‘The Extra pilot went on to conduct a textbook overhead join according to Conington’s procedures, but unfortunately didn’t see the EV97 that was downwind. For his part, the EV97 pilot saw the Extra late, and thought it was in an inappropriate position because he didn’t think its pilot had followed the correct overhead join.
Apart from the unfortunate fact that the Extra pilot didn’t see the EV97, the key learning points were: the Extra pilot to prefix his calls with “transmitting blind, receiver failure” to make it clear that he wouldn’t hear any transmissions; review procedures at Conington to ensure effective and timely passing of messages; pilots to be clear about their airfield joining procedures so that they know the expected tracks; and be aware of any likely conflict points in the circuit just in case other aircraft are joining ‘radio-failure’ for real and may not see you already established in the circuit.’
Shoreham Hunter accident anniversary AAIB statement
David Miller, AAIB Chief Inspector of Air Accidents, issued this statement on 21 August. ‘Today marks the first anniversary of the Shoreham Air Display accident, the worst in the UK since the Farnborough Airshow in 1952. Our thoughts are with all those affected by this tragedy.
‘We have published three Special Bulletins which have included safety recommendations to prevent future similar accidents. Our final report (which is expected to be published later this year) will integrate and expand on those previous bulletins, which dealt with systemic issues, and cover the technical aspects of the accident itself.’
Rockwell Commander 114B: see ‘Poor weather, fatal outcome,’ opposite
Piper Saratoga II TC suffered ‘unexplained power loss’: see story below