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The Fall of EgyptAir 990

It is not hard to think of reasons why EgyptAir 990 might have become an ordinary—or even an extra-ordinary—target of intense observation. EgyptAir 990 was, first of all, a foreign carrier from a country that is not always regarded as a close United States ally. Second, it was carrying, in addition to its civilian passengers, thirty-three Egyptian military officers, including one brigadier general.11 During their visit to the United States, the thirty-three officers were, according to the Defense Department spokesman, Kenneth Bacon, subdivided into six distinct groups: the members of one group were here to study communications; a second group was testing recently purchased helicopters; the third group was here to receive “training on high frequency” equipment; the fourth group was learning about telecommunications; the fifth group was studying the repair of Chaparral missiles; the members of the sixth group were carrying out individual projects.12 Whatever their separate missions, they had all convened to take this particular flight for their return to Cairo.

A third possibility is that EgyptAir 990’s passage through W-105 might have come as a surprise to the military and might therefore have provoked special attention. Any one of the three possibilities could have operated in isolation,13 or in combination14 with one another. (And, of course, none of the three may have taken place: the plane may have been tracked by the Air Force radars simply because all civilian planes are at all times being similarly tracked.)

But what of the third possibility I have mentioned: What reason is there to think that EgyptAir 990 could have surprised military observers in the region (and therefore become a closely scrutinized object)? Just this: the flight surprised at least one civilian air controller that night. The automatic computer reports that would ordinarily have made EgyptAir 990’s passage from one sector to the next wholly unsurprising for civilian controllers were not functioning flawlessly; perhaps the communications between civilian and military controllers were also flawed.

At the point where the plane was being handed off from the New York controller at Kennedy to the New York controller at Manta, the Manta controller expresses dismay and impatience that the flight has not been entered into the computer:

Kennedy Controller: Manta, Kennedy manual handoff, EgyptAir 990.

Manta Controller: Doesn’t anybody know over at the tower that they’ve got to put these flight plans back in?15

The NTSB provides among its documents a description of the fact that, as part of a normal procedure, the computers had been shut down for a routine repair. It is true that the controllers don’t seem to find their situation abnormal (“Let me see if there’s anything in here. Of course not. And I don’t have all his routing either. Oh, that’s wonderful”). But neither do they find it acceptable (“It’s just disgusting”). There is no question that the handoff from the Kennedy to the Manta sector is safely executed: the Manta controller does not have the route in the computer, but the Kennedy controller recites it orally (“Shipp Linnd Lacks Dovey”); the Manta controller does not have the pilot’s requested altitude, but the Kennedy controller provides it (Manta: “Do you know what he wants as a final?” Kennedy: “I’ve got thirty-three thousand”).

This first phase of the air controller’s complaint lasts slightly less than one minute and should probably be seen against the backdrop of complaints in every other line of work. But the point is not whether anything wrong happens here; the point is that if the flight isn’t in the Manta controller’s computer, will it—at the point ten minutes later where the flight is directed by the Atlantic controller to veer east into W-105—be in GIANT KILLER’s computer? A July 15, 1999, agreement between the East Coast FAA air controllers (“hereinafter designated Center”) and the facility (“hereinafter designated GIANT KILLER”) specifies that even when the warning zones are released to the FAA, the civilian planes “penetrating” the air space have to be announced to the military by explicit procedures, such as computer notification.

The conversation between the Manta and Kennedy controllers comes to a halt because the Manta controller has to exchange information with two planes, first EgyptAir 990, then Costa Rica Airlines 661, called a “Lacsa.” But five minutes later the Manta controller is still upset and returns to the subject, asking the Kennedy controller: “You got any more surprises after this Lacsa coming off, or is he the last one?” An important clarification now follows. What has upset the Manta controller is not that all the flight reports have failed to be put in the computer. The problem is that they have been entered there inconsistently:

Manta Controller: …Nobody typed in the EgyptAir but they did type in the Lacsa.

The Kennedy controller tells the Manta controller that he has no “tickets” (advance information) about planes that he will be forwarding to the Manta sector, but he then goes on to note that the lack of a ticket doesn’t mean there won’t be any more planes: “Just because you don’t have a ticket on anybody doesn’t mean there’s nobody else.”

Manta Controller: …So, we’re both gonna be in the dark.

Kennedy Controller: Well, there ya go.

The element of surprise audible in the Manta controller’s statements to the Kennedy controller (“You got any more surprises…?”; “Nobody typed in the EgyptAir but they did type in the Lacsa”; “We’re both gonna be in the dark”) is registered in at least one other radar sector as well.16

Small tremors of unease about the plane’s route occur at various places in the air traffic control record. While the plane is still on the ground back at JFK, the Kennedy Tower ground controller expresses concern. The plane is two hours late taking off; does the filed flight plan still hold?17 He consults the controller in charge of flight data (“Is that flight plan still good?”) and is assured that it is (“Yeah. That’s still good”). Should the plane be given a new transponder code? He is assured: “The code that he has is good.” The time is 12:56. Twenty-three minutes later (at 1:19 AM), when the Kennedy Tower local ground controller transfers control to the New York traffic controller, he recalls his original worry: “I’ve got an EgyptAir 990 going over Shipp…. It’s on an older strip; Center says it’s still good.”18

Later, when the plane is being placed in the Manta controller’s hands, the Manta controller expresses lack of confidence about using the computer to pick a flight path: “OK. Let me start a track…pick. This new equipment—I don’t even know how to do this stuff. Enter. There he is. OK. Interim two three oh [altitude 23,000 feet].”19 Again, these passages are cited not to suggest any transgression or lapse of attention on the part of the air traffic controllers, who seem alert and concerned, but to suggest their shared unease about sending EgyptAir out into a night on which everyone seems to be somewhat “in the dark.”

Was EgyptAir 990 the only civilian plane flying through the W-105 region, as appears to be the case in the two-hour20 period covered by the air controller transcripts? (The question is worth asking because a solo plane entering W-105 might startle military onlookers in a way that a steady stream of civilian planes would not.) If EgyptAir 990 was indeed the only civilian plane in the warning zone, there seems to exist a simple and straightforward explanation: it is late at night; few planes are flying; and most of those that are flying are not embarking on a transatlantic flight. Costa Rica Airlines 661, heading for home, flies straight down the coastline; Lufthansa 8202, a cargo plane which had stopped at JFK in its travel from Frankfurt to Atlanta, now flies south-west over Robbinsville, New Jersey, and continues south. There is, however, one other flight setting out on a transatlantic journey, the cargo plane El Al 2812. It prepares for takeoff almost simultaneously with EgyptAir 990. The controller begins to instruct El Al 2812, traveling to Tel Aviv by way of Frankfurt, to exit from JFK Airport by the Kennedy seven departure lane (the same gateway EgyptAir 990 flies out of). But the controller then instructs the pilot to follow a different path:

Kennedy Tower Controller: El Al 2812, good morning, you’re cleared to Frankfurt via the Kennedy departure seven—Actual[ly], it’s a Bette two departure and Nantucket transition….

El Al 2812: Roger, El Al cleared to Frankfurt via Bette two Nantucket transition gateway….

The air route from JFK to the Bette intersection, and from Bette to Nantucket, is the path taken by transatlantic flights when W-106 and W-105 are in use by the military. (It is the path both TWA 800 and Swissair 111 traveled.) The fact that this route is used when military exercises are underway does not mean that the path cannot be used when the W-106 and W-105 regions are open to civilian planes. But the fact that the cargo plane’s flight route was along the Bette path and EgyptAir 990’s was not (like the fact that Costa Rica Airlines’ flight was typed into the computer and EgyptAir 990’s was not) calls attention to the isolation of EgyptAir 990 on its middle-of-the-night voyage home.21

Given the higher level of danger that exists in a military warning zone than in open seas, prudence and ordinary investigative precision would seem to mandate a reconstruction of that environment. Details from the route have been given here not because they show something wrong,22 but because they are a reminder that the world external to the plane is at least as complicated as the one inside the plane that has already for many months now undergone intense review.

2.

The EgyptAir 990 crash, according to repeated NTSB announcements, involved no mechanical mishap, or at least no mechanical mishap that has so far been recognized on its sophisticated data recorder.23 Electromagnetic interference should be scrutinized as a possible cause, even in plane crashes where a mechanical explanation seems to exist, since the mechanical event itself may have been triggered by a prior electrical event24 ; but the absence of any mechanical explanation (as so far appears true of EgyptAir 990) should increase the rigor with which data concerning radio and radar transmitters in the area is gathered and studied.

It is striking that the tiny handful of stark facts known about the fall of Egypt Air 990 are themselves consistent with electromagnetic interference. Here are the four facts we know. One: the plane’s autopilot disconnected. Two: the plane went into a sudden steep dive. Three: the elevators on the plane’s tail, the movable surfaces on the horizontal portion of the tail that control the pitch of the plane (by determining whether the plane’s nose points up, down, or level), acted anomalously, moving independently rather than in coordination with each other. Four: the two engines turned off (shortly before the transponder, and presumably all other electrical systems, lost power).

These four features of the EgyptAir 990 catastrophe are all prominent in the most important literature on electromagnetic interference—the 1988 Air Force study of military craft and the 1994 NASA study of civilian craft by Martin Shooman.25 I will consider them in turn, beginning with the disconnecting of the autopilot.

The 1994 NASA study contains an appendix in which individual pilots summarize incidents caused by electromagnetic interference. Here are excerpts:

Autopilot malfunctions commuter airliner…

Manual A/P [Autopilot] disconnect…

Unmotivated A/P [Autopilot] disconnect, business transport…. In stable cruise, sudden A/P [Autopilot] disconnect resulting in -5 pitch down…

Helicopter reported interference to Auto Pilot and rotor controls in vicinity of Navy Ship with high power. Problem associated with cable pick up of RF [Radio Frequency]. Same problem identified several times.26

How does an autopilot disconnect in situations of electromagnetic interference? There are two ways. The auto-pilot (as in some of the examples above and, again, as in the late phase of the Swissair 111 accident) may automatically disconnect, either because it receives a stray electrical command which shuts it off or because it becomes baffled by the random information it is receiving and so shuts down. A second possibility is that the human pilot sees that an order he or she did not authorize is starting to be carried out on one of the plane’s control surfaces (such as its rudder, elevators, ailerons, or wing flaps). When this happens, it is appropriate—indeed necessary—for the pilot at once to disconnect the autopilot. (The second passage above describes pilot intervention.) It is perfectly plausible that the EgyptAir 990 autopilot may have disconnected on its own27 ; it is equally plausible that the pilot, seeing something amiss, quickly and appropriately disconnected the autopilot.

The NASA researcher Martin Shooman points out that the disconnecting of the autopilot, whether executed by the autopilot itself or by the live pilot, becomes necessary to the plane’s survival (since the autopilot is starting to put the plane on a disastrous course). But, at the same time, that act of disconnecting is itself an especially hazardous event. Up to that moment, the autopilot has been receiving false instructions (such as an adjustment to the elevators, or a deflection of the rudder); but if the errant instruction is incompatible with safe flying, the autopilot will simultaneously start compensating for the false command with balancing counteractions. When suddenly the autopilot is turned off, the human pilots are abruptly confronted with a set of events that may be confusing, and there may not be time either to put in place or to undo the compensatory settings on other control surfaces.28

Eight seconds after EgyptAir 990’s autopilot disconnected, the plane entered a sudden steep dive. Especially telling on this matter is the previous work carried out by the Air Force on electromagnetic transmissions. Although the 1988 Air Force study, and the three-year-long Pentagon study it prompted, have still not been released to the public, the study’s major findings were summarized by Colonel Charles Quisenberry, one of the study’s authors: he stated that electromagnetic interference can send a plane or helicopter into an uncommanded roll or dive.29 Electromagnetic interference can take scores of different forms. But Colonel Quisenberry did not list scores of outcomes. Because he was giving a summary, he listed only the three most important, one of which was a sudden, uncommanded dive. Sudden dives are also registered in the 1994 NASA study of civilian craft: one commercial airliner dropped 30,000 feet; a second commercial airliner dropped 20,000 feet.30

The prominence of inexplicable dives in accidents involving electromagnetic interference makes it seem odd that the NTSB has so far not named it among possible causes in need of investigation in the case of EgyptAir 990, especially given the fact that this same geographical region had been implicated in two earlier plane fatalities, thereby increasing the possibility that the cause of all three involved the external environment.

The third key event (the position of the aircraft’s elevators) is closely related to the second. Elevators are among the surfaces whose control can be interfered with by electromagnetic transmission. When Colonel Quisenberry reported that planes can enter a sudden dive, he meant that some control surfaces on the plane (elevators, rudder, wing flaps) can be altered in such a way that the plane goes out of control and begins to fall.31

The fourth event, the sudden shutting down of the engines, is also a prominent part of the literature on electromagnetic interference. If we return to Colonel Quisenberry’s stark summary of the Air Force study, we find included in his short list of key events the sudden interruption of the fuel flow to the engines.32 This can be rephrased as “sudden turning off of the engines” since when a pilot (or a stray electrical signal) turns off the engine, what that command does is interrupt the fuel flow. Reports of the sudden turning off of engines also appear in the 1994 NASA study: a blimp suddenly had a double-engine failure at the moment when it was passing directly over a powerful Voice of America antenna in North Carolina.33 In another case, one engine of a plane ceased at the same time that the autopilot disconnected when in an area of strong transmissions.34

Because human beings and stray electrical signals can each introduce “commands” into the control surfaces of a plane, it is extremely difficult to sort them out, and at the same time crucial to do so.35 Decoupling the two is difficult enough in the early stages of the catastrophe; it is even more difficult once the catastrophe is fully underway. Once EgyptAir 990 had entered its steep dive, it may be that all subsequent command actions were initiated by the pilots, desperately trying to regain control of the plane and making the best decisions they could: those actions may have been a highly competent effort to save the aircraft or they may have been, however admirable, less competent. It is possible that all four of the key events—automatic pilot shutdown, steep dive, split-elevator anomaly, engine shutdown—were caused by electromagnetic interference or that only some of the four were caused by electromagnetic interference, the rest by pilot intervention and attempted rescue.36

Electromagnetic interference affects different planes in different and sometimes quirky ways because it interacts with a particular plane’s greatest points of electrical vulnerability: if a plane has chafed wiring (as in the case of TWA 800), it may produce a problem there; if a plane has an over-ambitious entertainment system (as has sometimes been claimed about Swissair 111, though the Canadian Safety Board has repeatedly stated that it has, for them, no more prominence in the accident than any of the plane’s other electrical system), the problem could first appear there. If it was a highly digitized plane (such as EgyptAir 990’s plane type, the 767), it could interact by introducing a false command into the autopilot, ignition, stabilizer, or other control surfaces.

The National Transportation Safety Board is usually scrupulous about not claiming to know a cause before having the evidence. It can sometimes be faulted for omissions, such as not reconstructing the external environment, or not bringing the same standard of inquiry to bear on military actions that it brings to bear on the actions of wire manufacturers or maintenance personnel or civilian passengers. But it would be hard to describe it as ever committing a faulty act. Its stamina in moving through four years of investigating TWA 800 without ever prematurely claiming to have found a definitive cause is remarkable.

It is therefore almost incomprehensible how this same Safety Board has come so close (at least as its statements are reflected in the media) to accusing the copilot of EgyptAir 990, Gamil al-Batouti, of willfully murdering 216 fellow travelers. The Safety Board officials acknowledged before Congress and before the public that they so far have insufficient evidence to hold Mr. Batouti responsible for the catastrophe; but to many onlookers (including this author) what they call insufficient evidence looks instead like no evidence at all.37 It certainly does not appear to be the case that only a pilot’s willed action could bring about the disastrous events (autopilot disconnect, dive, split-elevator anomaly, engine shutdown) that took place that night.

By gathering and providing to the public transcripts of the air controllers’ tapes, FAA logs, communications from the Virginia Capes Surveillance Facility, and many other materials, the NTSB has already begun to carry out a reconstruction of what might have happened. It is to be hoped that this is the first step in what will eventually become a comprehensive review of the external electromagnetic environment. Such a review has still to be carried out for the three planes that have, since July 1996, crashed after leaving JFK Airport.

—This is the second part of a two-part article.

…We have a variety of radar around the country that is used to defend our territorial integrity, to monitor air traffic. Obviously, there’s a huge amount of air traffic coming in and we monitor it all the time…and special monitoring—

I suppose they do exercises and they do a variety of other things, trying to improve their capabilities.

  1. 11

    I have specified one brigadier general, even though the number varies, depending on the news source, from one to three. According to Jane’s Defence Weekly, the group of thirty-three officers included “two Egyptian Air Force brigadier generals and two army major generals” (Vol. 32, No. 19, November 10, 1999).

  2. 12

    Defense Department, Pentagon News Briefing, November 4, 1999.

  3. 13

    Taking the second as an example: United States military observers may have been aware of the plane and its special passengers long before the plane left the ground and all along its route. (Kenneth Bacon has stated that the presence of thirty-three officers is not unusual: one thousand Egyptian officers come to the United States each year.)

  4. 14

    For example, if United States military observers were notified of the plane’s approach only very shortly before it arrived, they might give it special scrutiny. Once they began to scrutinize it, they would realize it was an Egyptian carrier. They might give it even closer scrutiny while checking the background of the flight, and discovering that thirty-three military officers were on board.

  5. 15

    FAA transcript of Manta Sector controller. (Here and throughout I have eliminated all “uh”s and “ah”s between words registered in the transcripts; and I have added punctuation.)

  6. 16

    The Atlantic controller, for example, has no record in her computer of the Navy plane Arise 57; so the Kraft controller faxes a record to her (“one invalid field record…on its way”). (Minute 1:32, FAA transcript for Atlantic Sector.)

  7. 17

    The clocks are changing from Eastern Daylight Savings on this night to Eastern Standard, and once the clock is set back, the flight delayed by two hours seems delayed by only one hour.

  8. 18

    FAA transcript for New York TRACON sector, 1:16 AM to 1:31 AM.

  9. 19

    Minute 1:25, FAA transcript for Manta sector.

  10. 20

    The period from 12:48 AM to 2:52 AM is covered by the five transcripts. Each only covers a segment of that period, and it is possible that the two-hour record for each of the five would show other planes traveling through the W-105 and W-106 regions.

  11. 21

    The Atlantic controller, as mentioned previously, enlists the help of many different civilian and military resources once she realizes the plane has disappeared from radar. Among them are Lufthansa 499 (a nonstop flight from Mexico City to Frankfurt) and Air France 439 (a nonstop flight from Mexico City to Paris), the first of which tries to contact EgyptAir 990 on the radio and the second of which is actually conscripted into digressing from its own route to fly over a patch of the ocean to see if any sign of the plane can be seen. But by the time these two planes are called on for help, EgyptAir 990 has already been under the sea for a long time (thirteen minutes in Lufthansa’s case; forty-five minutes in the case of Air France). Though various searchers are looking over Dovey, northeast of Dovey, and even as far off course as W-102 (see map), by the time the controller is in contact with Air France she appears to have inferred what will eventually turn out to be the actual accident site, for she requests that he search for the plane “sixty miles south of Nantucket,” the description now widely used for describing the location of the fall. (Minute 2:32, transcript of Atlantic sector.)

  12. 22

    The air controller tapes from the Swissair 111 flight, in contrast, show something unequivocally wrong, even if we cannot yet judge the relation between the plane’s thirteen-minute radio blackout and its eventual fall.

  13. 23

    Although the initial causes of the TWA 800 and Swissair 111 accidents have not been found, there are recognizable physical problems along the way: an explosion in the central fuel tank in the case of TWA 800, “arcing”—a hot and persistent form of electrical sparking—in twenty wires located near the cockpit in the case of Swissair 111. Nothing equivalent has been found in the case of EgyptAir 990, except the four events involved in the final dive, looked at below.

  14. 24

    Two examples involved a Boeing 767-300, the type of plane involved in the EgyptAir 990 crash. In 1993, a 767 attempting to land at Frankfurt suffered a sudden rudder deflection of 16 degrees which sent it off the runway. The event was judged to have been instigated by electromagnetic interference (“Government Officials Investigated United 767 Rudder Incident,” Aerospace Daily, September 21, 1993, Vol. 167, No. 57, p. 473).

    In 1991, an Austrian-owned Lauda Air 767 suddenly went into a fatal dive near Bangkok when one of its thrust reversers was deployed. British aviation authorities, who had originally assisted Austrian investigators in their inquiry, surmised in a 1995 report that electromagnetic interference might have caused the thrust-reverser deployment. Boeing spent a year trying unsuccessfully to duplicate such an outcome experimentally, but they investigated only electromagnetic interference originating from the relatively weak signals on passenger-carried cell phones and computers, not the potentially more powerful signals that could have originated from radios and radars operating in the external environment.

    The 1995 British Civil Aviation Authority report is cited in Andrew Laxton, “New Theory on Lauda Crash: Passengers may have set off Lauda Air Disaster,” South China Morning Post, May 7, 1995. Both the 1995 report and Boeing’s year-long attempt to confirm it are described in Business Week, October 14, 1996 (Christina Del Valle, “Could a Laptop Bring Down an Airliner?”), and in South China Morning Post, April 21, 1996 (Jane Moir, “Probe Back at Square One 5 Years After Lauda Crash”).

    The official accident report issued by the national safety board of Thailand does not explicitly mention electromagnetic interference, but does repeatedly call attention to the possi-bility that the thrust reverser (whose activation entails a combination of hydraulic and electrical systems) may have been initiated by an “electrical wiring anomaly” such as a “hot short,” possibilities they could not fully explore due to the destruction of the wiring during the crash. (See section 2.5.3, “Electrical Systems Failure Resulting in Deployment,” in Aircraft Accident Investigation Committee, Ministry of Transport and Communications Thailand, Lauda Air Luftfahrt Aktiengesellschaft Boeing 767-300ER Registration OE-LAV, Dan Chang District, Suphan Buri Province, Thailand, 26 May BE 2534 (AD 1991), pp. 32, 33; and see also Appendix C, pp. 64-68, on the Electrical Control System of the thrust reverser and engine).

    Three months after the accident, the United States FAA issued an Airworthiness Directive that “required the deactivation of all electrically controlled B767…thrust reversers until corrective actions were identified to prevent uncommanded in-flight thrust reverser deployment” (as summarized in Thai Aircraft Accident Investigation Committee report, 2.5.4, paragraph 4). By February of 1992, Boeing had carried out design changes in the fleet of B767s reflecting their new requirement that “critical wires” be isolated and given “protective shielding.” (Thai Aircraft Accident Investigation Committee report, section 2.7, item 3.)

  15. 25

    For a description of the 1988 Air Force and 1994 NASA reports, see “The Fall of TWA 800,” pp. 59, 60.

  16. 26

    Appendix D, Description of Events,” in Martin Shooman, “A Study of Occurrence Rates of Electromagnetic Interference (EMI) to Aircraft with a Focus on HIRF (External) High Intensity Radiated Fields,” April 1994, National Aeronautics and Space Administration, Langley Research Center, pp. 93-96 passim.

    Additional instances include the following: “When the HF [High Frequency] transmitter was keyed during EMC [Electromagnetic Compatibility] testing the autopilot would indicate a rolling dive…”; “Cabin lights and 1 engine shut down. Pilot took action to reset autopilot…”; “High frequency transmitter effects autopilot on a narrowbody”; “Effect was…loss of autopilot, multiple and rapid data fail flag oscillations/ pilot loss of confidence in primary displays while bus is blinded…”; “HF [High Frequency] transmitter interference into autopilot…potentially very dangerous.”

  17. 27

    The fact that no warning alarm went off at the moment the autopilot disconnected has been widely cited in the press as evidence that the autopilot must have been disconnected by the pilots; but no such conclusion can be reached on the basis of an absent alarm. The Vienna Institute of Aerospace-Medicine and Space-Biology points out that the same electrical event that knocks out the autopilot can also disable the auditory alarm (“Faulty EgyptAir Device Suspected,” The Boston Globe, November 25, 1999). Similarly, Byron Acohido, a reporter for the Seattle Times, cautions that alarms are often disabled by a stray electrical signal (quoted in Jean-Paul Mari, “EgyptAir: Le Suicide Était Presque Parfait,” Le Nouvel Observateur, December 15, 1999, p. 43).

  18. 28

    Conversation with Martin Shooman, October 31, l997 (two years before, and hence not referring to, the EgyptAir 990 accident). See Shooman, “Occurrence Rates,” p. 4, for an incident in which electromagnetic interference causes a problem with one engine; the autopilot compensates; the pilot then notices the engine problem and disconnects the autopilot; but now the compensatory actions of the autopilot have been interrupted and the plane enters a sudden dive.

  19. 29

    Colonel Quisenberry, cited in “The Fall of TWA 800,” p. 60, notes 7-10.

  20. 30

    Shooman, “Occurrence Rates,” p. 4 and p. 95 (case 40). Sudden dives, however, play a less prominent part in the NASA study than in the Air Force study because the NASA report is primarily about nonfatal electromagnetic events: it is based on accounts by living pilots, pilots who survived the incidents they are describing. As Martin Shooman points out, one reason electromagnetic interference is not adequately studied is that, in many cases, either its effects are short-lived and therefore may appear harmless, or they are fatal, in which case the pilot does not survive to inform us about it. One advantage of the Air Force study (and the three-year Pentagon study it motivated) is that it investigated accidents—such as uncommanded rolls and dives—that were fatal to the crews.

  21. 31

    The Vienna Institute of Aerospace-Medicine and Space-Biology, in consultation with Austrian pilots with vast experience of the Boeing 767, has surmised that a possible cause of EgyptAir 990’s catastrophe was a “stabilizer runaway” that then caused an automatic disconnect of the autopilot. A stabilizer is a horizontal rudder on the tail that, as the name implies, usually keeps the plane level, but can, in the case of a runaway, tilt the nose down. (See “Faulty EgyptAir Device Suspected,” The Boston Globe, November 25, 1999.) The anomalous position of the elevators could have been part of the runaway, or could reflect the effort made by the pilots to override the stabilizer runaway by adjusting the elevators.

  22. 32

    See “The Fall of TWA 800,” pp. 59-60.

  23. 33

    Shooman, “Occurrence Rates,” p. 6. In this case both of the electronic engine controls were burned out, although in other cases engines stopped without suffering permanent physical damage.

  24. 34

    Shooman, “Occurrence Rates,” Appendix, p. 93 (case 14). Effects on the engine other than a straightforward shutdown are also included in the NASA report: “H[igh] F[requency] transmitter interference with ana-log engine governor controls caused engine to surge. Varied with frequency…” (Appendix, p. 96, case 56). One oil pressure sensor inside an engine was affected by high-frequency transmissions (p. 96, case 54).

  25. 35

    Recovered data boxes and cockpit voice recorders can greatly help to sort out which events in a given accident were initiated by the pilots and which events had some other source. But even these sources of information are not always decisive, and sometimes they are simply wrong. The data recorder can indicate events that investigators know did not take place: one altitude parameter on the TWA800 data recorder gave invalid readings and had to be ignored by investigators (NTSB “Flight Data Recorder (FDR) Group Chairman’s Factual Report,” February 15, 2000, revision, p. 5). Conversely, it can fail to announce events that investigators know did take place: in the case of Swissair 111, the smoke in the cockpit at 9:14 PM and fire soon thereafter are not registered on the data recorder, according to lead investigator Vic Gerden. If we did not have the exchange between the pilot and the air controllers, we would not know these key events had taken place.

  26. 36

    Of the four events, only the last—the shutting down of the engines—currently has evidence suggesting that it was an act brought about by the pilots: the data recorders and voice recorder indicate that the instruction to shut down the engine, or at least partially shut it down, originated in the cockpit. Because this particular event took place thirty seconds into a dive of terrifying speed and angle (40 degrees, during one interval), it has been proposed by a number of analysts that the turning off of the engines may have been an accidental act—that the pilot may have been reaching for a different lever altogether (see Byron Acohido, “Pilot Could Have Confused Similar Switches on 767’s Control Panel as Plane Plunged,” Seattle Times, November 18, 1999) or the pilot may have tried to slow the engines down, an appropriate act in an emergency descent, but may have gone too far. (See C.J. Chivers with Matthew L. Wald, “EgyptAir Data Recorder Shows Engine Shutdown,” The New York Times, November 13, 1999, p. A7.)

    Throughout public discussions of EgyptAir 990, the shutting down of the engines (whether by human hands or by malfunction) has been spoken about as guaranteeing the doom of all on board. Whenever the shutdown has been assigned to human hands, the action has been talked about as self-evidently sinister. But the record of those rare plane crashes where some people survive complicates the picture.

    Once a crash is inevitable, a pilot may decide to turn off the engines immediately prior to impact in order to decrease the hazard of fire. In 1989, United flight 232 (a DC-10) crash-landed in Sioux City, Iowa. Twenty seconds before impact the pilot instructed the crew to “Ease the power back” and then to shut down both engines (“Close the throttle…Close the throttle”). The copilot—an off-duty pilot who had been traveling as a passenger but who assisted the crew as soon as the difficulties began—declined to follow the pilot’s instruction since he was steering the plane by means of unequal power in the two engines (transcript cited in St. Louis Post-Dispatch, September 20, 1989).

    It has never been suggested that this pilot intended to harm himself or others by his instruction to turn off the engines. On the contrary: the pilot and crew have been deservedly praised for their ingenuity, their teamwork, and their ongoing deliberations; large passenger plane crashes in which anyone survives are extremely rare, and in this case 186 of 296 passengers survived. The pilot’s instruction is a reminder that nonsinister reasons can motivate the impulse to shut off the engines shortly before impact. (EgyptAir 990 was near the bottom of its first dive when its engines shut off; the pilots would have had reason to believe that the impact was seconds away, though as it happened, they then successfully repositioned the elevators and the plane began to climb.)

    A second crash in which a remarkable number of people survived occurred in 1996 when an Ethiopian Air flight was hijacked, ran out of fuel, and, as a result, lost first one, then both engines. The plane then crash-landed with both engines off in the waters near Comoros: 53 of the 178 passengers survived. (The Ethiopian plane was a 767, as was EgyptAir 990; so the EgyptAir crew was likely to know the history of the Ethiopian plane.) The fact that the Ethiopian Air crash is (along with the United crash in Sioux City) almost alone among large passenger plane crashes in having survivors and that its impact occurred with its engines off is noteworthy; for it shows the error of assuming, in the case of EgyptAir 990, that the engines being off ensured the death of all on board, just as the United pilot’s instruction shows the error of assuming that the decision to turn off engines could only be motivated by the desire to kill oneself and others.

    It may be that while a plane still has a chance of not crashing, the engines should be kept running. But once the crash of a plane is judged by its pilots to be both certain and soon, there appears to be some argument to be made for turning the engines off.

  27. 37

    The NTSB’s first public announcements about the recovered voice recorder (midday, Monday, November 15, 1999) described the conversations between the pilots as friendly, and reported that the crew had worked together cooperatively to try to undo the catastrophe. But by 5:00 PM on that same day, a different account began to emerge from the NTSB that dominated the press for many months and focused attention on three or four separate sentences spoken by the pilot or copilot.

    The copilot, Gamil al-Batouti, according to an unnamed law official, had said, “I’ve made my decision.” (It went almost without saying that “my decision” was the decision to kill himself and 216 people on the plane, rather than a decision about a course of action to take when first sensing trouble on the plane.)

    On November 19, 1999, NTSB Chairman Jim Hall announced to the public that the voice tape actually contained no sentence even remotely resembling the sentence “I’ve made my decision.”

    Once that sentence was gone, there still remained a second sentence, a “mysterious utterance” by the pilot who had “uttered a prayer” or “muttered a prayer” and done so “in Arabic” or, as some newscasts reported, “in Persian.” (The designation of the language alone seemed to imply wrongdoing, even though pilots from non-English-speaking countries routinely use their own language when not speaking with the air controller; most of the Swissair 111 cockpit recording, for example, is in Swiss German.) Little thought was given to the possibility that the pilot could have observed some problem with the plane and called on God to help him; the prayer was instead widely interpreted as voicing the intention to commit suicide and mass murder. Soon, however, the “sinister” quality of the prayer began to erode, as did even its “mysteriousness” or “portentousness.” The prayer turned out to be part of the texture of everyday life, a sentence spoken by many Egyptians an estimated two hundred times a day and by many Egyptian-Americans thirty times a day.

    Sometimes the pilot’s question to Gamil al-Batouti—”Did you shut the engine?”—has been cited as though the pilot is accusing Mr. Batouti of turning off the engine. The full transcript suggests the strong possibility of the reverse interpretation: the pilot (rightly or wrongly) wishes to make certain that the engine has been wholly or partially shut down. He first asks the question “Did you shut the engine?,” then restates it as an instruction: “Shut the engines”; and only when the copilot assures him, “It’s shut,” does he proceed to the next instruction to “Pull with me,” apparently in an effort to change the position of the elevators.

    The sentence “Pull with me, pull with me,” spoken by the pilot to Gamil al-Batouti, has been widely interpreted as implying that Mr. Batouti was not cooperating with his fellow pilot and had to be urged into cooperation (according to this view, the pilot recognized that Mr. Batouti had intentionally plunged the plane toward the sea, but hoped to pull him out of his maniacal act by several brief imperatives). The words “Pull…Pull…” were spoken five years earlier by a pilot to his copilot when their USAir flight 427 plunged toward the ground near Pittsburgh. The same sentences were then widely cited in the press without anyone inferring that the copilot was being uncooperative or suicidal.

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