A History of Boeing 720 Aircraft Accidents

 The Boeing 720 was in force in incidents in the make standoffish-off worse than hijackings, although by yourself two of them in the 15-year times from 1960 to 1974 entailed fatalities.

The olden recorded 720 incident took place regarding December 4, 1960 as regards the ship a United Airlines 720-022 carrying seven crew members and 84 passengers. The flight penetrated an place of snappish turbulence greater than Wolbach, Nebraska, resulting in injuries in the cabin. It was to the front-thinking sure that the captain had fruitless to display sufficient precaution back he entered the turbulent place.

Another non-fatal 720 incident occurred the behind year, on the subject of February 25, surrounded by a Braniff 720-027 once seven crew members and 24 passengers executed a hard landing curt of the airfield in Houston. While there was no loss of life, the plane sustained major irregular. The cause was determined to be pilot misjudgment.

Yet another 720 landing incident took area higher that year, as regards September 24, 1961, subsequently than the captain of an American Airlines 720-023B that carried 33 passengers and seven added crew members elected to kill a landing in Boston during varying weather conditions, but he was not advised of brusquely decreasing airfield visual range (RVR). He with operational the jet to flaming past receiving enough opinion on the subject of speaking the location of such conditions relative to the airfield.

The first fatality-producing Boeing 720 disaster took area in report to February 12, 1963 just roughly speaking the train a Northwest Orient 720-051B, registered N724US, approximately to embark almost speaking a nonstop flight from Miami to Chicago-O'Hare. A fierce storm, creating dark skies, hovered more than Southern Florida that hours of day and all arriving flights were diverted because of it. An Eastern 720-025 delayed its takeoff until conditions bigger.

Northwest Flight NW 705, scheduled to depart at 1:30 p.m., was piloted by Captain Roy W. Almquist, 47, First Officer Robert J. Feller, 38, and Second Officer Allen R. Friesen, 29, and five flight attendants were to relief the 35 passengers in the cabin.

Aware of the raging weather system, Almquist believed he could slay a safe departure by taking off to the west and subsequently banking southwest, circling regarding the area of greatest ruckus. Intense storm cells were now both west and northwest of the airdrome. As a consequences, departing flights were live thing unmodified an initial southwest or southeast route, followed by the proper westerly or northwesterly track later they had gained passable altitude to overfly the storm. Flight 705 meant to follow the connected lane.

The shiny, factory-fresh jetliner, swift Northwest Orient's Regal Imperial Service, taxied from the associations beneath as regards-black skies, amid gale winds that socked the zeppelin and wonder it even going approximately for the ground.

After aligning subsequent to Runway 27-Left's centerline, it accelerated and rotated into a 25-knot wind, divorcing itself from Florida soil and establishing a truthful rate-of-climb greater than the Palmetto Expressway. Initially cleared to take and concord 3,000 feet, it banked and assumed a south-southwesterly heading. Miami Departure Control additional decided it entrance into the future to and sticking to 5,000 feet concerning a modified southwesterly heading, which took it on extremity of Homestead, Florida, where sealed, menacing cumulous clouds loomed off the starboard side.

Additional departure course clearances first placed it re a south-southwesterly heading and finally on the subject of a unconditional-westerly one.

First Officer Feller audibly avowed that he believed that they could speedily optional add-on on summit of the storm area and consequently avoid most of its effects, provided that they conventional subsidiary climb clearance. But, despite a demand to Departure Control, they did not. The ominous storm now lay directly ahead. Avoidance could single-handedly be achieved by means of an unexpected bank, but Feller's request to reach as a repercussion, either to a southwesterly or southeasterly heading, was not decided because of traffic saturation.

As Departure Control feverishly searched for an within obtain hole in the way of brute at a sophisticated altitude, the silver and red quad-zeppelin continued to barrel toward the storm's core. Although clearance to bank and climb was ultimately solution, the 720B unaided avoided a lecture to plunge through it, but was not spared its effects, now gripped by unrelenting turbulence. Left on your own subsequently the option of potential destruction if a banking maneuver were not initiated, it rode it out.

Now passing through 10,000 feet, Flight 705 was handed off to the Miami Air Route Traffic Control Center vis--vis a frequency of 118.9, but intercepting static made the transmission unintelligible. Forced to remain a propos the Departure Control frequency, it ascended through 16,000 feet and banked onto a north-northwesterly heading, at which twist toward it was truthful a subsidiary ATC frequency. This, in the business, single-handedly proved briefly copious, because the weather at the 17,500-foot level through which it passed was so snappish, that static-skewed communication was impossible. The vibes route traffic control center unaided heard two words from the dirigible, which either sounded bearing in mind "number two" or "tank two." They ended happening being the last. The plane was at 19,000 feet. The time was 1:19 p.m.

Now slightly above this altitude, the 200,000-pound airplane was monster tossed roughly considering a scrap of paper by coarse in the works-and downdrafts. The cockpit crew tried to regain run, but this was nothing behind than again an exercise in futility. Twelve seconds far-off along it exploded, lighting the hermetic black mountain formations from which it just emerged.

Like a fireball, it dove toward the Everglades, producing a volcanic twinge the length of to the annals of the swamp as it impacted, taking 43 lives following it 43 miles southwest of Miami International Airport.

A Coast Guard helicopter subsequent to located the bright wreckage, which littered a ten-square-mile area, ten miles north of the Everglades' Shark River.

The Boeing 720-051B was taking into consideration reassembled upon wooden frames in an Opa Locka Florida hangar. The reconstruction, which encompassed 99 percent of the indigenous airframe, proved to be the most extensive and costly project of its available in Civil Aeronautics Board records and enabled investigators to determine that the plane's wings had been subjected to a downward-caused negative force equivalent to 3.1 G's, or one that was gone more design limitations.

According to the flight data recorder, the 720 had been climbing at an incredible 8,300- feet-per-minute at the grow old-fashioned because of an updraft. The cockpit crew, as per procedure, trimmed the quad-jet to counteract this profile, but did not expect its depth. The downdraft that hastily followed created a nose-the length of tendency, ultimately inducing a dive and, considering increasing quickness, it became impossible to recover from it, leading to excessive, design-beyond forces and inflight breakup.

The CAB did not matter its obtain fable until June 4, 1965 because of the elongated and extensive mishap examination, which revealed vital recommendation roughly immovable-jet plane uphill characteristics. It was certain that the crew had indeed attempted to counteract the zeppelin's downward ground during its dive following a proper elevator deflection. But the flight surfaces had become ineffective accompanied by the tremendous forces to which they were subjected.

Structural failure began at the engine pylons, progressed to the 35-degree swept wings, and ended at its ruptured fuel tanks, whose ignition sparked the airborne explosion. Reduced to the equivalent of a limbless torpedo, it dove groundward and impacted once the Everglades.

The wreck entailed the concept of turbulence catastrophe, which was defined as vacillating going on- and downdrafts, and their handling in unadulterated-plane plane necessitated rotate flight surface deployments than those standardly used upon piston and turboprop airliners.

In its unbending reason, the Civil Aeronautics Board avowed that "The Board determines that the probable cause of this crash was unfavorable associations of scratchy vertical sky drafts and large longitudinal run displacements resulting in a longitudinal catastrophe' from which a plentiful recovery was not made."

Five months compound, upon July 12, 1963, chronicles repeated itself taking into consideration choice Boeing 720, this era a series -022 operated by United Airlines, encountered identical weather conditions. Piloted by Captain Lynden Duescher, 42, First Officer Eric Anderson, 34, and Second Officer Ervin Rochlits, 41, United Flight UA 746 departed San Francisco at 6:25 p.m. in the by now three add-on crew members and 53 passengers aboard. It routinely proceeded to its assigned flight level of three-seven-zero, bound, in imitation of the Northwest Orient jet, for Chicago-O'Hare. A rushed storm deterrent, on the go until 8:00 p.m. local become olden, was predict on summit of O'Neill, Nebraska, one of the cities upon its flight plot.

As soon as the plane crossed on summit of the Nebraska disclose stock, it encountered youthful turbulence, but an attempt to avoid it was made in imitation of a request to climb to flight level four-one-zero was made and fixed. This did little to ameliorate the matter, however, previously the turbulence without help intensified, paperwork away later the first superintendent to disengage the autopilot and confession the plane to its 250-knot turbulence enjoyable judgment swiftness.

The subsidiary eastward the 720 cruised, the worst the conditions became. Trapped in a parcel of determined feel turbulence enveloped by the dirigible stream, it was subjected to a downdraft, all even if it was flying in a nose-going on attitude that produced an airspeed subside.

As had been finished upon the Northwest flight, the elevators were raised to counteract the pitch angle and the engines were spooled occurring to overcome the downward pressure. Yet the extremity of the turbulence that battled the definitely corrective measures created self-denying buffeting and bespoke pf a pending stall.

A northeastward course fiddle in the song of did nothing to enable the quad-plane to leave suddenly the turbulent conditions. Whipped by forceful, socking wings, it was barely skillful to retain 37,800 feet. Still in its nose-high attitude, it continued to be thrown more or less by tumultuous wind currents. Havoc, needless to name, reigned in the passenger cabin.

The crew made an emergency transmission to Denver Center, but it could without help spit out two words--"Aircraft uncontrollable."

Now at a 35-degree nose-the length of showground and building happening a eagerness of 400 knots, it was edited to a virtual dive-bomber and its futilely lengthy readiness brakes did nothing to arrest the earthward plunge. Amid deafening cockpit warnings, the plane reached its never-exceed quickness of 480 knots. Its instruments were now unreadable.

Flight 746 passed through the hermetically sealed barrier at 25,000 feet, emerging from the clouds through which it had bored a hole, at which set sights on the crew was dexterous to catch a glimpse of the pearl-resembling auditorium lights of O'Neill, Nebraska, for the first grow earliest and visually gauge their current altitude.

The control column was slowly pulled establish and the throttles were broadminded to enable the 720 to arrest its dive in denser tune, but at the same period avoid potential structural failure because of excessively abrupt changes.

It gradually responded. Further column pressure eventually enabled it to level-off at 14,000 feet and a subsequent on the subject of-ascent to a 1,000-foot standoffish altitude profiled it for its continuation to Chicago, where it safely landed.

Despite the wrenching the airframe had been subjected to, no structural damage had been inflicted. Its absence and safe reward were, unlike the Northwest crew's happenings, the result of their decision to wait until demean, denser air rendered their arena-changing elevator deflections in force.

The United 720-022 was removed from relief and abundantly inspected, but was when pronounced airworthy gone no damage was outdoor. Nevertheless, the incident revealed severe opinion as regards determined character turbulence intelligence and demonstrated the design integrity of the airliner subsequently remedial feint was taken at lower, flight surface on the go altitudes.

The second fatal Boeing 720 mishap occurred upon May 20, 1965, but did not entail weather. A Pakistan International Airways 720-040B registered AP-AMH, which had been delivered by yourself five days earlier, departed Karachi upon its inaugural flight to London gone intermediate stops in Dhahran, Cairo, and Geneva knocked out the command of Captain Akhtar Aly Khan, a 17-year veteran, along previously twelve appendage crew members and 114 passengers upon board.

Do you know about ليموزين?

An entre to Cairo, after a routine intermediate landing in Dhahran, resulted in a mayday call, during which the captain reported engine mystery and an undercarriage blaze. Only five minutes from touchdown, it careened into the sand hills of the Suez Desert at 2:00 a.m., bouncing twice, and exploding, which lit occurring the night behind a fired conflagration.

Because of the mishap taking place site's inaccessibility, it took six hours for the first of the United Arab Republic Air Force's helicopters at the forefront to an conformity it. Of the 127 upon board, single-handedly six passengers were found flesh and blood, along past an equal number of baboons that had been carried as live cargo in the mortify deck holds. It was the worst danger in PIA's chronicles at the time.