American Airlines Flight 587

American Airlines Flight 587 (AAL587), registered as N14053, an Airbus Industrie A300-605R, crashed in Belle Harbor, Queens, New York on November 12, 2001, killing all 260 onboard, 5 on the ground and injuring 1 ground survivor, nearly a month to the day after September 11, 2001 with public belief of a second terrorist attack overpowering.

Not long after the crash the U.S. Army Corps of Engineers found the A300’s vertical stabilizer, minus rudder, floating in Jamaica Bay and the focus turned from terrorism to the aircraft and crew. The NTSB investigated and eventually blamed the co-pilot, Sten Molin, and Airbus rudder design as “Probable Cause”: http://www.ntsb.gov/publictn/2004/AAR0404.pdf (a must read to understand the background of the incident and this article).

The NTSB report, which makes no effort to name the flight crew, is possibly the most unpardonable railroading of innocent casualties doomed by a previously damaged aircraft who did nothing amiss to merit their fate. The captain was Ed States and first officer was Sten Molin.

AAR0404, aside from the above, is an excellent report, excluding its fictitious wake turbulence and allotment of blame, namely in its detail of the “Progressive Failure” of AAL587’s tail fin. The fin didn’t snap off in one go; its main and transverse mounts progressively failed beginning at the aft and progressing to the fore in two separate stages with the second episode occurring roughly 15 seconds after the first.

This article highlights the physical improbabilities, to put it politely, of the NTSB’s “Probable Cause” conclusions authored to neatly absolve American Airlines of the real responsibility for the disaster: AAL’s failure to repair latent damage in N14053’s empennage tail fin mounts caused by a brutal encounter with clear air turbulence over the Caribbean in 1994.

The NTSB accident report alleges that AAL587 encountered wake turbulence from a Boeing 747, Japan Airlines Flight 47 (JAL47), after takeoff from JFK runway 31L on 11/12/01 and the co-pilot’s rudder pedal inputs to evade the turbulence fatally stressed the vertical stabilizer to catastrophic destruction, all permitted to occur by the Airbus rudder design.

The laws of physics dismiss the NTSB’s wake turbulence claim and the A300 worldwide fleet operational history dismisses the co-pilot rudder input/sideslip story.

Great briefer on wake turbulence right here: http://www.scribd.com/doc/3996595/AC9023F-Wake-Turbulence

AAL587 took off from Runway 31L about 1m40s behind JAL47 and maintained this interval throughout. Runway 31L faces Manhattan so aircraft heading to southerly or easterly destinations are required to commence an abrupt left turn after wheels up to Canarsie VOR (CRI) or the BRIDGE non-directional beacon (NDB). JAL47 flew the wider Breezy Point Climb toward CRI and AAL587 flew the tighter inside arc Bridge Climb toward BRIDGE. AAL587 never neared within 1nm laterally of JAL47’s departure route or any height close to the 747’s wake turbulence sink window. The prevailing winds and direction were nowhere near strong enough to push the 747’s rapidly dissipating vortices into AAL587’s path and altitude. In short, there wasn’t any wake turbulence to encounter.

Both the A300 and 747 are ‘Heavy’ class aircraft with the 747 the heavier of the two; meaning that the A300 can fly into and withstand a 747 wake turbulence thrashing without much ado. Under Federal Aviation Administration wake turbulence separation rules, heavy aircraft are required to maintain minimum 4nm abaft any immediately preceding heavy.

AAL547 never approached within 5nm of JAL47, never approached within 1nm lateral and always maintained 2000’ or greater vertical separation at every secondary radar return of the way as unmistakably clear on the NTSB report’s superimposed flight paths of the two aircraft.

Wake turbulence is at its most perilous, as the above link explains, from “HEAVY-SLOW-CLEAN” aircraft. This turbulence also rapidly dissipates after generation and sinks in the region of 500’-to-900’/minute. A heavy 747 (A380 jumbo-class didn’t exist yet) aircraft flying slow speed in clean configuration produced the greatest wake turbulence in civil aviation, rapidly dissipating while sinking at the maximum rate. The wingtip vortices are the largest component of this turbulence by far and they begin generating spirals just as the aircraft becomes airborne. Spirals don’t generate on takeoff roll because the tarmac impedes their formation. On Nov. 12, 2001, the most perilous wake turbulence from JAL47 was generated after takeoff at V2 and reached peak strength after the crew soon retracted gear then takeoff flaps while on or around V2 accelerating toward 250kt. AAL587 flew past JAL47’s peak wake turbulence region without a bump.


The highest wind recording at JFK a half hour before AAL587 lined up on 31L was 20kt and this dropped to 10kt by the time the A300 took off. The left wingtip vortices of JAL47 moved at the vortices’ outward and upward rotational velocity against a 10kt headwind. On gear up and flap retraction into this headwind the left and right vortex rotational speed was circa 180kt/h at point of generation and moving outward and upward perpendicular to the aircraft’s direction of travel while pushed backward by 10kt/hour headwind. When the 747 turned left toward CRI turning out of a 10kt headwind into a 10kt crosswind, the left wingtip vortices spiraled outward and upward at initial vortex generation speed with the bottom half moving rotation speed plus 10kt and the top half battling the 10kt wind and oblating, increasing in diameter to no greater than the 747 wingspan with the left vortex trail pushed southerly at 10kt/h. As this occurred, the right wingtip vortices slammed into the 10kt wind. Both rapidly lost energy while sinking, since heavy, at circa 900’/minute for 1080’ descent in the 1m40s separation between the two aircraft. After the 747 had traveled 5nm the vortices generated 1m40s earlier were now completely dissipated and blended into the atmospheric turbulence of a 10kt wind almost 1000’ above AAL587’s route at every step of the way and more than 0.5nm off the A300’s right wing.

The wake turbulence thrown off by a 747 on takeoff hit peak strength under zero wind. There is no atmospheric turbulence in calm wind conditions vortices to crash into and additionally dissipate the sinking vortices which are free to rotate in increasingly larger spirals until using up their energy.

Airline Transport Pilots know wake turbulence when they encounter it. The first officer’s “What the hell are we into[?],” recorded on the HOT-2 mic, suggest that the crew, since at a loss to explain their predicament, were in uncharted territory of airframe dynamics.

At 9:15:36am EST, something big and very loud rocked AAL587 at 1750’ in a climb and 250kt and couldn’t have been wake turbulence, or collision with another aircraft or any airborne object. The first loud bang was the rear vertical stabilizer right side main lug mount snapping in half. The next loud bang seconds later was the remainder of the stabilizer mounts progressively and swiftly ripped in two or else torn from the empennage while still attached to the fin. The vertical stabilizer was gone and the aircraft was now uncontrollable.

The destruction of the right rear main lug severely compromised the vertical stabilizer mounting strength. It was no longer a match for any rudder deflection. Being broken now the fin was subject to greatly enhanced torsion and flex by even minimal rudder deflection, lethally vulnerable against the forces of 250kt relative wind from substantially reduced mounting strength to hold down in place. Like a structurally critical but flawed building crane tie-on strap snapping, causing the crane to keel over, overstressing and snapping all other straps, pitching and burying the crane no longer tied to the building into a condo across the street as occurred in New York City over a year ago. Or damaged rudder mount on a sailboat. Turn the tiller and the rudder is torn free from the transom or rendered useless.

The lug fracture, in conjunction with the co-pilot and captain’s zero awareness of the dire circumstance and co-pilot’s unwitting continued rudder use, created a domino effect that eventually tore the fin off without either pilot ever knowing why.

After the catastrophe, the NTSB went into the simulator, based on presumed wake turbulence, negligent co-pilot rudder conduct and completely airworthy aircraft, and sought out means to graphically depict how the co-pilot could rip a tail fin out of an airworthy aircraft at 250kt. This trial by computer simulation from unsubstantiated presumptions is an excellent example of ‘Begging the Question’. This was no impartial investigation. The NTSB ruled the aircraft certified airworthy doomed by the co-pilot “overreact[ing]” to wake turbulence along with the insinuation that Airbus’ rudder design enabled pilot overuse and abuse without adequate damper restraint.

The Flight Data Recorder and American Airline’s aircraft operational history and maintenance records dismiss this second conclusion acquired by manipulative human intervention via creative computer simulation.

The A300 rudder deflected a maximum 9.3 degrees at 250kt by automatic damper restraint. The rudder pedals on AAL587 extended 4” in either direction from neutral. The co-pilot’s right and left pedal inputs never exceeded 2” of movement in unison with equal direction yoke movement, until after the fin was gone and the co-pilot, still unaware, applied the full 4” travel in desperation to maintain level controlled flight, holding it there until impact, all in vain.

At only one instance, lasting one second, did the co-pilot induce sideslip with 1.6”-2” of right rudder in contrast to 30 degrees left aileron, a non-issue for an airworthy A300 fin but calamitous for a severely weakened mounting system in induced sideslip or not. The co-pilot’s rudder deflections exacerbated an already dire predicament not of the co-pilot’s doing. There were no rudder inputs, none at least published by the NTSB, preceding the initial bang that triggered the co-pilot to apply rudder inputs.

The NTSB accident report maintains that the co-pilot “overreact[ed]” with “cyclic rudder motions” that were “too aggressive, and…unnecessary.” The aircraft was “certified” “airworthy” with a rudder design “susceptible” to “potentially hazardous rudder inputs.”

The co-pilot reacted to a major unexpected roll event, not caused by turbulence but by the tail fin systematically tearing off, and tore off because the same empennage was hammered by severe clear air turbulence in 1994 and the latent damage induced in result never even inspected.

From 1995-2001, twelve Service Difficulty Reports from A300 operators worldwide involving the aircraft’s empennage were filed with the Federal Aviation Administration. There were no details of which components of A300 empennages specifically encountered service difficulty but no trends were identified. None involved the fin mounts or the NTSB report would’ve indicated so, and each difficulty, whatever they were, were satisfactorily addressed by subsequent maintenance/repair. (p.41)

There was no filing of any SDR by American Airlines about the 1994 turbulence incident over the Caribbean because AAL never even notified the FAA.

47 of 221 onboard were injured by powerful invisible air currents en route to Puerto Rico, the plane managed to landed uneventfully and AAL never submitted so much as the flight number or date.

The only evidence of any post-incident diligence by AAL are maintenance hub “work cards” announcing intended future plans that the “vertical stabilizer torque box was to be inspected externally for distortion, cracks, pulled or torn fasteners, or damaged paint.” (“was to be” the key words) The ‘was to be’ which never was also included external inspection of the rudder system, and if any damage was visually discovered, the full slate of internal inspection would follow. No work card of this tentative planned inspection was submitted to the FAA either. There is no record on AAL company file, SDR or maintenance work card that any inspection even occurred.

Yet on the basis of mere work cards only announcing a planned inspection, as opposed to concrete proof of full teardown and meticulous microscopic examination of every cubic nanometer with 47 physical injuries of varying severity as all the impetus necessary, the NTSB report insists that AAL did carry out a “special inspection.” Only the NTSB has no record to back this claim, since none was ever filed. A most unprecedented assertion by the NTSB.

The simplest answer is that no external inspection ever occurred. If did, there would be work cards on record as proof, SDR or not, and the FAA, therefore NTSB, would have these and would’ve included them in AAR0404, which they didn’t.

No inspection occurred because AAL never bothered to perform one. The aircraft was immediately returned to service after landing in Puerto Rico. From the remainder of 1994 to November 12, 2001, whatever latent difficulties incurred by that clear air turbulence remained in the aircraft’s empennage unchecked. Every subsequent departure was a macabre lottery and AAL587 happened to draw the short straw.

The legendary story of United 232 in 1989, a DC-10 that crash landed in Sioux City, Iowa, demonstrated that a microscopic crack, invisible to extensively trained, highly experienced, especially vigilant maintenance staff, and in this case the tail engine fan disk, can bring down an aircraft after thousands of service hours from the tiniest latent flaw with no warning.

The Caribbean clear air turbulence incident must’ve damaged one or more of AAL587’s vertical stabilizer mounts with the tail fin most vulnerable and taking brunt of abuse. All it takes is a microscopic crack in one mount exposed to seven years of normal usage, numerous other turbulence encounters, maybe even a tail strike or two, to eventually fail. None of the latent damage was detectable by walk around inspection or internal visual inspection, but only by complete tear down of the entire empennage and full spectrum technology examination of every cubic micron. It never happened. Moreover, the paint on these aircraft is so flexible and resilient that it can survive cracking even after tremendous abuse as the recent Fed-X MD-11 crash in Narita shows. Hence checking for and finding no paint cracks, indicate nothing.

Airline transport vertical stabilizers are so tough that it takes incredible abuse to defeat them, and 4 degree or 11 degree sideslip at 250kt in 11-22kt wind (see report) just isn’t going to win the battle, nor the energy released by clear air turbulence powerful enough to send 47 walking wounded or on ambulance stretcher passengers to Puerto Rico hospital emergency rooms.

In a tragic 2002 midair t-bone at 35,000’ near Uberlingen, Germany, the vertical stabilizer of a pressurized Boeing 757 cargo flight tore a pressurized Tupolev Tu-154M in half, both traveling at cruise Mach, roughly 480kts ground speed, perpendicular to the other. The top 80% of the 757’s fin with rudder was sheared off but the mountings, as if matters now, held in place. Not even the high speed ground impact through big unyielding trees separated the mounts from the empennage. A tragedy that macabre demonstrated the strength of these mountings and the extreme unlikelihood of the NTSB’s preconceived simulated AAL587 conclusions.

There has never been a rudder pedal-induced separation of an A300 fin at 250kt, even amid severe turbulence. And if 2” of right rudder pedal input producing 4.65 degree rudder deflection in a 4-11 degree left sideslip in a 25 degree left roll, were catastrophic abuse, the entire A300 fleet, starting with the original test flights, would’ve crashed years ago. As each of these aircraft have been subject to the identical cyclic rudder/aileron configurations as AAL587 was many, many times over. The difference being: these other A300 empennages weren’t hammered by devastating clear air turbulence.

The AAL587 fin minus rudder, spotted by the U.S. Army floating in Jamaica Bay, had plummeted untold hundreds of feet, smashing into the brick-like water, rapidly descending below the surface, and floated back up essentially unscathed. The rudder, likely first to hit, was torn off on water impact. Soon after the discovery the NTSB found another U.S. airline transport pilot, as the mortal remains of the co-pilot and the 264 other victims filled a makeshift morgue, to go on record, anonymously, and criticize the co-pilot Molin as a rudder-aggressive loose cannon while tactfully balancing this out with complements from a different captain and a flight engineer. The critic captain never bothered, possibly due to forgot, to file any complaint or concern with the airline or FAA at any point prior to the crash. If the co-pilot really were loose cannon, AAL would know about it, as would the pilot-in-command that day. Thus, why would AAL employ the co-pilot armed with this knowledge of unpredictable volatility and, if did, why would the captain let them fly the aircraft that morning?

The answer, once again, is simple. The co-pilot was the opposite of loose cannon. AAR0404 is gross character assassination of unjustifiably deceased via computer simulated artifact of what didn’t happen.

The only causal factors to ever tear the vertical stabilizer off an airline transport jet in midair, dooming the aircraft, were midair collision or hidden structural flaw, both the consequence of multi party human error and oversight.

Contrary to the NTSB, AAL587 was ultimately doomed by damage incurred from severe clear air turbulence in 1994, seven years of subsequent service, and American Airlines’ failure to diligently address, identify and repair latent microscopic cracks in the aircraft’s vertical stabilizer mounts that eventually failed. The co-pilot and 264 others, including 5 on the ground in Belle Harbor, were the innocent human casualties. Each had a name, family, friends, a past. What they didn’t have was an independent U.S. federal government agency, charged with the responsibility of ensuring and promoting aviation safety, shouting down and fending off powerful lobbying pressure to blame everyone but the entity genuinely culpable: American Airlines.

American Airlines’ failure to diligently inspect and repair structural empennage damage to N14053 incurred from clear air turbulence over the Caribbean in 1994 led to the preventable deaths of 265 people on November 12, 2001 in Belle Harbor, NY.