Safety Mat­ters

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

Pilot - - CONTENTS -

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

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