AF­TER­MATH

Over­tak­ing into a col­li­sion

Flying - - Contents - By Peter Gar­ri­son

In Septem­ber 2014, a Cessna 172 over­took and col­lided with a home­built Searey am­phib­ian on fi­nal ap­proach to the Buf­falo-lan­caster Re­gional Air­port (BQR) in Lan­caster, New York. The 172 pi­lot, 78, with 2,500 hours, and his 14-year-old pas­sen­ger died when their air­plane spi­raled out of con­trol and crashed.

Re­mark­ably — since one tends to think of midair col­li­sions as un­sur­viv­able ac­ci­dents, with both air­planes spin­ning out of the sky in pieces — the Searey fared much bet­ter. The 172’s pro­pel­ler had taken a chunk out of the Searey’s right wing and par­tially sev­ered its aft fuse­lage a few inches ahead of the em­pen­nage. The 4,500-hour pi­lot, 59, heard a loud sound but had no idea of its cause. Per­ceiv­ing that he had lost pitch con­trol from the stick — prob­a­bly be­cause the el­e­va­tor, even if its ca­bles were not sev­ered, was just mak­ing the en­tire em­pen­nage flop up and down — he guessed that some­thing in his re­cently built air­plane might have bro­ken. The Searey con­fig­u­ra­tion is sim­i­lar to that of the Icon A5 (and, an­ciently, the Repub­lic Se­abee), with the pusher en­gine sit­ting atop the high wing and be­hind the cabin. Find­ing that he could use power from the high-mounted en­gine to keep his nose down, he was able, with ad­mirable air­man­ship, to make a con­trolled crash land­ing. Nei­ther he nor his pas­sen­ger, a 9-year-old girl, was in­jured.

Al­most ex­actly two years later, and at a place not many miles dis­tant, an­other midair col­li­sion took place. This one in­volved a Cessna 120 and a Piper Cherokee 140, and was sim­i­lar to the other in that the Cherokee over­took the Cessna and its pro­pel­ler sliced off the 120’s em­pen­nage. The 120’s left land­ing gear, in turn, sev­ered the left wing of the Cherokee. The Cherokee’s pi­lot and his pas­sen­ger died, as did the other pi­lot, who was alone in the 120.

In both ac­ci­dents, the over­tak­ing air­plane closed slowly on the one ahead, and there­fore its pi­lot could have had the traffic in sight for some time be­fore the col­li­sion oc­curred.

Nei­ther en­counter was ran­dom: In both in­stances, the air­planes were part of a planned ac­tiv­ity. In the case of the 172 and the Searey, the pi­lots were tak­ing part in an EAA Young Ea­gles event in which lo­cal pi­lots give rides to young peo­ple to in­tro­duce them to gen­eral avi­a­tion. The pi­lots had been briefed to de­part straight out and fly for 10 miles along the north side of an elon­gated rec­tan­gle bor­dered by two roads 2 miles apart. They were then to turn to the right and re­turn to the air­port along the south side of the rec­tan­gle be­fore en­ter­ing the traffic pat­tern at mid­field on a cross­wind leg. The route was to be flown at 1,800 feet, ex­cept that air­planes were to be at 1,560 feet (field el­e­va­tion is 752 msl) on the cross­wind leg. The col­li­sion oc­curred at a height of 1,625 feet, just as the Searey pi­lot was pre­par­ing to make the right turn to cross­wind. The Searey had climbed slightly,

In both ac­ci­dents, the over­tak­ing air­plane closed slowly on the one ahead, and there­fore its pi­lot could have had the traffic in sight for some time be­fore the col­li­sion oc­curred.

and the Cessna had de­scended. The Cessna’s ground­speed was 90 knots, and the Searey’s 70.

Pi­lots had been in­structed to make po­si­tion re­ports at sev­eral land­marks along the course, and the Searey pi­lot said that he had done so. The 172 pi­lot ought, then, to have known there was an air­plane some­where not far ahead of him. A com­puter sim­u­la­tion con­ducted by the Na­tional Trans­porta­tion Safety Board showed that the Searey would have been vis­i­ble at the bot­tom of the Cessna’s wind­shield for some time be­fore the col­li­sion. The NTSB noted, how­ever, that the Searey, seen from di­rectly be­hind and pre­sent­ing its small­est cross sec­tion, would have been “a small dot in the ter­rain” un­til sec­onds be­fore im­pact and, fur­ther­more, “would have pre­sented lit­tle rel­a­tive mo­tion to the other pi­lot, mak­ing de­tec­tion more dif­fi­cult.” All air­planes are small dots un­til they are about to hit you, how­ever, and with a clos­ing speed of only 20 knots, the brightly col­ored Searey must have been more than a “small dot” for some time be­fore the Cessna hit it. Dot or not, the NTSB con­cluded the cause of the ac­ci­dent was the Cessna pi­lot’s “in­ad­e­quate vis­ual look­out for known traffic.”

The col­li­sion be­tween the Cherokee 140 and the Cessna 120, two years later, also took place in the con­text of an or­ga­nized event, though one less struc­tured than the EAA’S Young Ea­gles ac­tiv­ity. Weather per­mit­ting, a group of friends ha­bit­u­ally flew, in as many as seven air­planes, from their home field of Ham­burg, New York (4G2) to St. Marys (OYM) in Penn­syl­va­nia for Sun­day break­fast. The dis­tance is about 80 nm. On the cloud­less day of the ac­ci­dent, six air­planes were mak­ing the trip. Since the 85 hp 120 was the slow­est of the group, it de­parted first; the Cherokee took off 78 sec­onds later. Their flight paths con­verged four min­utes later, 6 miles south of the air­port.

Ac­cord­ing to one mem­ber of the group, the 120 pi­lot was usu­ally the first to ar­rive at 4G2 and the first to take off; af­ter that, how­ever, air­planes de­parted at ran­dom, when­ever they were ready. Un­less it was tur­bu­lent, they cruised at 3,500 feet and com­mu­ni­cated with one an­other on the un­of­fi­cial air-toair fre­quency of 123.45. They never at­tempted to fly in close for­ma­tion.

Such in­for­mal ar­range­ments are typ­i­cal when groups of pi­lots fly any­where to­gether. The logic of hav­ing the slow­est air­plane take off first is ob­vi­ous; oth­er­wise, all the oth­ers would have to cool their heels wait­ing for him at the des­ti­na­tion. The trip was short, but the dif­fer­ence in block time be­tween a 90-knot air­plane like the 120 and, say, a 175-knot Bonanza would still be half an hour. It would cer­tainly make less sense for the Bonanza to de­part first and the 120 last.

On the other hand, the scheme created a near cer­tainty that faster air­planes would over­take slower ones. Be­cause they had agreed to fly at the same al­ti­tude, and all would be fly­ing the same course on the same head­ing, the same prob­lem would arise as was de­scribed in con­nec­tion with the Sky­hawk and the Searey: The air­plane ahead would be a small, al­most sta­tion­ary, hard-to-see dot un­til the over­tak­ing air­plane was quite close to it.

A mem­ber of the group who dis­cussed the ac­ci­dent with the NTSB said that hence­forth they would have the fastest air­plane de­part first; the group had also dis­cussed equip­ping its air­planes with ADS-B traffic de­pic­tion.

Even though this ac­ci­dent was nearly iden­ti­cal to the other, this time the NTSB did not in­voke the for­mula of “in­ad­e­quate vis­ual look­out.” In­stead, it blamed the ac­ci­dent, some­what tau­to­log­i­cally, on “the fail­ure of the sec­ond air­plane’s pi­lot to see and avoid the first air­plane. ...”

Fail­ure to see is not quite the same as fail­ure to look, but it is hard to imag­ine, when two air­planes ap­proach each other so grad­u­ally, that they are not re­lated.

The NTSB noted, how­ever, that the Searey, seen from di­rectly be­hind and pre­sent­ing its small­est cross sec­tion, would have been “a small dot in the ter­rain” un­til sec­onds be­fore im­pact.

Newspapers in English

Newspapers from USA

© PressReader. All rights reserved.