Air Turbulence May Be Factor in Jetliner Crash, Officials Say

New York Times ^ | 11/14/01 | SHERRI DAY

[kattracks]

nvestigators said today that wake turbulence, or an air disturbance from a nearby aircraft, could have been a factor in the crash of American Airlines Flight 587, which broke apart shortly after taking off from Kennedy International Airport on Monday and plunged into a residential neighborhood.

The Airbus A-300, bound from New York to Santo Domingo, appears to have taken off from Kennedy Airport less than the standard two minutes after a Japan Airlines Boeing 747 jetliner took off, officials said.

Investigators said one of the plane's pilots could be heard on the cockpit voice recorder making comments about a "wake encounter." That could have been the Japan Airlines flight, which was four miles away, or about 800 feet higher and to the northwest of Flight 587, farther apart than they are required to be by aviation procedure.

Today's analysis of the air traffic control tower's radar data seemed to show that air turbulence could have been a factor, officials from the National Transportation Safety Board said. Although they are looking closely at that possibility, officials cautioned that the investigation was continuing and that no probable cause of the crash had been ruled in or out.

"We do not know if this really contributed in any way to the actual accident," Marion C. Blakey, chairwoman of the N.T.S.B. said at a news conference this evening. "But we are looking at this very closely."

Ms. Blakey initially said today that the American Airlines flight departed two minutes and 20 seconds after the Japan Airlines flight, but she later said, "We believe that in fact it was one minute and 45 seconds."

Ms. Blakey also said investigators were making "good progress" on the recovery of wreckage from the crash site. Both of the plane's engines are at Kennedy Airport, where they will be analyzed and later sent to Tulsa, Okla., for complete deconstruction. The plane's vertical tail fin was found in Jamaica Bay and is at Floyd Bennett Field in Queens. Preliminary analysis showed that there was no evidence that an outside object struck the vertical stabilizer, Ms. Blakey said. Investigators have also retrieved the plane's rudder, wings, nose and two black boxes.

Officials found the cockpit voice recorder on Monday and are using it to determine what went on inside the aircraft. The plane's second black box, the flight data recorder, was located on Tuesday. That recorder tracks an airplane's mechanical operations and will be compared with the cockpit voice recorder to gain a more accurate idea of what caused the incident, officials said.

George W. Black, a spokesman for the N.T.S.B., said today that the transcription of data from the second box had suffered a setback. A module on the box was damaged and had to be sliced open to recover the data, Mr. Black said. The N.T.S.B. sent the recorder to its manufacturer, which was able to recover the data.

"We have had the manufacturer repair the problem and we are reading out the data as we speak in Washington," Ms. Blakey said. "We hope we will have good information for you very shortly on the specific technical characteristics of the flight."

This evening, investigators were still trying to figure out why the Flight 587's vertical tail fin and rudder broke off in flight and landed in Jamaica Bay, while the main portion of the plane fell into a beachside Queens neighborhood in the Rockaways, just three minutes after the plane took off.

Mr. Black said such a break had happened only a few times before, in at least one case, during a trial of a B-52 bomber.

"There have been tail section fractures before over the years, but most of them were a long time ago." Mr. Black said. "There's certainly nothing in our database like this."

While N.T.S.B. officials said they have not ruled any cause for the crash of Flight 587 in or out, the preliminary evidence does not appear to point to a terrorist act or an explosion. The National Transportation Safety Board is still the lead agency on the crash. If criminal intent were found, the Federal Bureau of Investigation would take over, officials said. On Tuesday, Barry W. Mawn, special agent in charge of the F.B.I.'s New York office, said the agency had already begun to take some evidence from the site as a precautionary measure.

None of the 260 people on board the flight survived, officials said. Five other people who lived in Belle Harbor, the neighborhood in Queens where the plane crashed, are missing and are presumed dead, officials said.

Mayor Rudolph W. Giuliani said on Tuesday that 262 bodies had been recovered. This afternoon he said that figure remained unchanged, a fact that he said was encouraging because there had been some worry that as many as 10 people on the ground were missing.

The mayor also urged families of the victims to take advantage of the grief and counseling services at the Jacob K. Javits Convention Center in Manhattan, which include gathering specimens of DNA to aid in the identification of victims' bodies and helping families to obtain visas to the Dominican Republic to bury the dead. Most of the families have registered at the site, but he encouraged those who had not come forward to do so.

After visiting both Belle Harbor and Washington Heights on Tuesday, the mayor said he wanted to bring the two communities together for a joint memorial service. Washington Heights, a neighborhood in northern Manhattan that was home to many of the crash victims, has the densest population of Dominicans in the city. Belle Harbor, a predominately white neighborhood, is also a community in mourning, as at least 75 of its residents were firefighters, police officers or civilian workers who were killed at the World Trade Center as a result of the terrorist attacks on Sept. 11.

"They are communities that have great deal in common," Mr. Giuliani said. "They share a great faith in God. They have a very strong reliance on family. They have very strong connections to each other, and they have a very very strong work ethic. These two communities are much more similar than they are different, and they share something else now and that is massive and disproportionate loss."

Meanwhile, at a news conference outside of the Javits Center this afternoon, community leaders from Washington Heights asked the federal government to grant amnesty for Dominican immigrants who are afraid to come forward to identify their loved ones' remains because they are living illegally in the United States.

"There's a lot of illegal immigrants here that have lost relatives, that have lost families, and they're torn," said Fernando Mateo, president of the New York State Federation of Taxi Drivers, which lost six of its members in the crash. "They don't want to come forward and identify their dead wives, their husbands, their parents, only because they're not here legally. They fear that if they say who they are, they're going to be eventually deported."

Mr. Mateo said six immediate family members of Monday's crash victims had approached him with this problem so far, but he feared that dozens more were in the same situation.

On Tuesday, Senator Charles E. Schumer said he had received a commitment from the Justice Department to expedite visas for people who want to travel from the Dominican Republic to New York to attend funerals. Mr. Mateo said that offer should also be extended to illegal aliens in New York who want to travel to the Dominican Republic to bury the dead. After doing so, they should be allowed to re-enter the United States, Mr. Mateo said.

[chadsworth]

The EMP, if used as a weapon does not destroy as in an explosion or impact. The effect of the EMP results is a disruption of the electrical system, effectively disabling the controls as well as communications. Although the control systems are hydraulic, the hydraulic controls are servo fed and controlled devices that require electrical signals to tell it what to do.

It might be advisable for you to get all of your rocks gathered up before you start throwing them. :-)

[jlogajan]

The effect of the EMP results is a disruption of the electrical system

One natural EMP weapon is a lightning strike -- which hit airplanes frequently. Hence they are hardened against it, especially the fly-by-wire types. So the likelyhood of a raghead in a dingy aiming his Acme EMP-ray at craft 3000 feet up and bringing the bird down is -- very very small.

[chadsworth]

My friend, if you will kindly recall the recent advances in in EMP technology, which has had a tremendous amount of very recent research as the weapon of choice by those nations that have a large resource of scientists, you may be well advised to retract such a flippant statement.

In my opinion, Nita nupress may just have a very valid concern. Please review the web page listed below. I have included a short section identifying the Dept. of Defense concerns.

the scientist tinkered and soon put together two crude weapons. The smaller one was designed so it could be broken down into two parcels and shipped by United Parcel Service from one terrorist to another. The larger was built into a converted Volkswagen bus. Both used ordinary spark plugs to generate the pulse, commercially available coils, common capacitors and simple copper tape. “We wanted to show that by backyard means a weapons system could be built that would have some effectiveness against our civilian infrastructure,” Schriner explained during an April 30 demonstration at the Aberdeen Proving Ground.

One incident that made U.S. military planners take notice of the threat occurred a few years ago when a U.S. Comanche helicopter flying out of the now-decommissioned Griffis Air Force base in Rome, N.Y., took out the entire navigational-aids system at the nearby commercial airport. The helicopter had generated a low-level RF pulse during a radar test “which ended up totally disrupting the global positioning system (GPS) being used to land commercial aircraft in Albany, New York, for a couple of weeks,” reveals James F. O’Bryon, deputy director of the Pentagon’s Operational Test and Evaluation Live-Fire Testing Center, which is studying the impact of EMP and RF weapons on U.S. military systems.

The military began testing Schriner’s prototype weapons last year in an effort to determine the vulnerability of common electronic devices such as desktop computers, medical pumps and monitors, home-alarm systems and police scanners. In tests so far, Schriner’s devices have temporarily disrupted all of them.

A high-powered weapon used by a terrorist could have a far greater impact than freezing computers or turning off intravenous pumps. To illustrate his point, Schriner presented a fictional case.

EMP CONCERNS AS WEAPON OF CHOICE

[justlurking]

I'd also like to know if a pilot would normally open the engine throttles full out, the way these pilots allegedly did or tried to do, in response to such turbulence.

I'd have to review the timing of the events, but I expect that the pilots spooled up the engines to max power in response to controllability problems. If the plane is wallowing and not responding to control inputs, the instinctive reaction is to increase airspeed by lowering the nose and increasing power because that's the sign of an imminent stall.

I don't claim to be a pilot, but I've been in a plane going through turbulence many times before, and I don't ever recall the pilot trying to "gun it" through the bumps.

In cruise, reducing power is the proper response. All planes have what is called a "manuevering speed", which is at the top of the green arc on the airspeed indicator and the beginning of the yellow (caution) arc.

At manuevering speed, full deflection of the controls will not overstress the airframe. Also, turbulent air will toss the plane around, but will not over-stress the plane because the wings and control services (like the tail) will stall before a structural failure will occur. If you are near the ground, this loss of lift is a problem, but at altitude you can still recover.

This flight was still at low altitude in a climb profile. They were almost certainly not exceeding the manuevering speed. That's why this whole thing about wake turbulence is bogus, unless they can conclusively prove that there was already a flaw that made the plane vulnerable.

[Nita Nupress]

So the likelyhood of a raghead in a dingy aiming his Acme EMP-ray at craft 3000 feet up and bringing the bird down is -- very very small.

Right. Just like the likelihood of a group of nineteen ragheads in hijacked airliners simultaneously aiming their airborne weapons of mass destruction at the World Trade Center twin towers 100+ stories up and bringing the towers down was -- very, very small.

By the way, the statement I posted above about "terrorists parked at the end of the airport runway to debilitate airplanes taking off or landing" was not made by some tin foil hat "conspiracist." It was made by the Chairman of the Special Oversight Panel on Terrorism of the Committee on Armed Services.

Your tendency for histrionic statements is yet another reason why you were not pinged to this conversation.

[LSJohn]

(BTW, another root canal coming up. Ugh.)

If it feels like one of the manual augers is going to come out of the top of your head, don't worry . . . . . . . very unlikey to go deeper than mid-brain.

[Cobra64]

There's air turbulence every day.

Jet wash is a definite factor. The next time you're flying, and the aircraft are stacked up waiting for takoff, there will be a minimum of one minute between full throttle times of the departing aircraft. I've been sitting on taxiways for over an hour in Richmond, and you can almost set your watch as the aircraft line up and take off.

[Cobra64]

Map, they don't use cassette tapes in a Walkman anymore. It's a little more high tech now. Digital flight recorder data is stored on "digital" micro chips. If you doubt technology, compare today's computer to what you had 10 years ago. As a parallel example, IBM is coming out with a 400gb hard drive within the next two years. Research labs are talking about molecular memory. Bell Lab's 1953 transistor technology will look like a stone arrowhead compared to today's GPS & laser guided munitions. A $1,000 pc today has more processing power (MIPS thoughput) than the largest IBM mainframe 20 years ago. Twenty gb of DASD today would fill up a warehouse of tape drives today.

[Cobra64]

An electromagnetic pulse (EMP) attack could incapacitate power grids, communications, computer systems, and even electronic infrastructure...

I've read a little about this. A re-directed microwave transmitter may be able to do what you're suggesting. I have a littany of ideas that the bad guys could use that are as effective and easier to deploy. I sent a note to the Feds but they seem to have "everything under control."

[Cobra64]

If you lose your rudder, hydro back up doesn't mean sh!t. You'll go into a spin; and if you have one engine at full tilt at 90,000 lbs thrust on one wing, and lost a wing and its thruster; well, your course is a vetical glide path.

[mommadooo3]

LOL... I don't 'look' like an EMP expert either. But methinks if an EMP were used, it would ALSO cause the flight/voice recorders to quit working. I'd think it's be 'easy' enough to check out. 'They' would look at the watches worn by the dead folks...see what time they all stopped. (if any survived the crash inferno, that is)

There are quite a few ground witnesses, that reported an expolsion/fire right before the pieces falling off/crash.

Hate to say this, cuz I'll get razzed, but where is Michael Rivero? His input may be helpful. He can think 'outside the box', and he seems pretty knowledgeable about things like this. Remember, he's our resident 'bulldog' who wouldn't let go of the deliberate downing of TWA 800.

[honway]

If the black box gets damaged from the fall from 1000 feet the only way it was "damaged" could be by explosion

That is a very good point.

[Brownie74]

Thanks for the ping. RadioAstronomer answered your question in post 25. EMP's will not cause structural damage to an aircraft but they will however fry all of the electronics on board the aircraft.

or a relatively small radio frequency weapon built from readily available technology could be used by terrorists parked at the end of the airport runway to debilitate airplanes taking off or landing.

That is what they mean when they say to debilitate.

The aircraft would have no radar, no radios, and no computers to drive the cockpit instrumentation.

[honway]

We believe that in fact it was one minute and 45 seconds."

The NTSB experts certainly know the standard for separation for a heavy jet behind a heavy jet is 4 miles. Either the radar track shows the approriate 4 miles was maintained or it was not. They should say so. Throwing out this 1 minute 45 seconds figure smells of a red herring.

[jlogajan]

where is Michael Rivero? .... He can think 'outside the box'

Yeah, but that "box" is reality.

[Map Kernow]

Map, they don't use cassette tapes in a Walkman anymore. It's a little more high tech now. Digital flight recorder data is stored on "digital" micro chips. If you doubt technology, compare today's computer to what you had 10 years ago. As a parallel example, IBM is coming out with a 400gb hard drive within the next two years. Research labs are talking about molecular memory. Bell Lab's 1953 transistor technology will look like a stone arrowhead compared to today's GPS & laser guided munitions. A $1,000 pc today has more processing power (MIPS thoughput) than the largest IBM mainframe 20 years ago. Twenty gb of DASD today would fill up a warehouse of tape drives today.

Well, you didn't really answer my question, but you gave me a doggone good bit of what looks like good info. So thanks. :)

[Map Kernow]

That's why this whole thing about wake turbulence is bogus, unless they can conclusively prove that there was already a flaw that made the plane vulnerable.

Thanks for your informative reply. I understand this morning that the Feds are still focused on the turbulence scenario, and are also focusing on the composition of the vertical stabilizer as a factor in the structural failure of the plane. Reportedly, the vertical stab. sheared off cleanly like it was cut with a Ginzo knife above the anchoring bolts. Supposedly the French Airbus company makes this part of the frame out of some composite that sounds like chewing gum and boogers. Now they're talking about examining the vert. stab.s and rudders in the whole AA fleet.

[Fred Mertz]

I believe the military is doing lots of directed energy experiments, not all of them EMP. Sorry, I don't have much to add to the discussion.

[Tommyjo]

The A300 that crashed was not fly by wire (FBW). Some of the secondary surfaces are digital controlled, but the primary controls such as rudder aileron and elevators are not.