AIR_FORCE_ENGINEER BARRY_STRAUCH BOB_MACINTOSH CAPTAIN_DAUGHERTY CAPTAIN_ERDEM COMMANDER_GRIEVE ENMANUEL_SOUFFRONT FIRST_OFFICER_ADCOCK FIRST_OFFICER_GERGIN FLIGHT_ENGINEER_GONZALEZ FLOYD_CARPENTER FRANCISCO_CUNHA GARRETT_HARENCAK GPWS INVESTIGATOR INVESTIGATOR_CARPENTER JIM_KRIEGER JOHN_COX KELVIN_GUERRERO MAINTENANCE_TECH MARY_SCHIAVO NARRATION NTSB_INVESTIGATOR PAPUAN_INVESTIGATOR PEDRO_MATOS PILOT_LINK PORTUGUESE_INVESTIGATOR PUERTO_PLATA_GROUND_CONTROL REBECCA_GRANT RELIEF_PILOT_EVRENESOGLU TECHNICIAN THOMAS_DUKE TODD_CURTIS TONY_MONETTI TRAINEE_CONTROLLER NARRATION At the heart of every modern aircraft is a computer that�s vital for safe flight. But those computers rely on a steady stream of accurate data. When they don't get it� � the results are sometimes catastrophic. How can computers designed to aid pilots hinder them instead? INVESTIGATORs search for the cause of three accidents triggered by bad data. Major Ryan Link and Captain Justin Grieve are ending a four-month deployment at Andersen Air Force Base in Guam. They�re returning home in a unique warplane, a B-2 Bomber called the Spirit of Kansas. It�s a seven-thousand-mile journey home from Guam to Whiteman Air Force Base in Missouri. Major Link is a qualified instructor on the B-2. Captain Grieve is the Mission Commander, with more than 2500 hours of military flying experience. The B-2 is only 80 feet off the ground and losing speed. The plane shakes violently. It�s on the verge of stalling. With the B-2�s price tag of two billion dollars, this is the most expensive aviation accident of all time. Operations of the entire B-2 fleet are suspended. The US Air Force appoints Brigadier General FLOYD CARPENTER to lead the investigation. Video of the takeoff shows that as the plane lifted off, it pitched nose high. INVESTIGATORs study the mechanical and computer systems that control the jet. They quickly determine that all the flight control surfaces were functioning on takeoff. The heart of the B-2 bomber is its computerized Flight Control System. On a B-2, pilots tell the computer what they want the plane to do, and the computer determines how to achieve that. So did something go wrong with that system? The INVESTIGATORs turn to data from the bomber�s flight recorder to discover what happened. AIR FORCE ENGINEER The nose is lifting off the ground, but the plane registers a pitch down of minus 8 degrees. Now obviously this plane is not pitching down, but the computer thinks it is. That is why it tried to lift the nose higher and higher and higher. General Carpenter wants to know why the flight computers were getting faulty data. Mission COMMANDER GRIEVE tells INVESTIGATORs that the pilots received an unusual computer message. Air Data Cal stands for air data calibration. There are 24 sensors near the nose of the B-2 that constantly measure air pressure. The plane�s computers use those readings to calculate altitude, air speed and angle of attack. If any of those 24 sensors provides an air pressure reading that differs significantly from the others, a re-calibration is needed to bring them all back into agreement. Less than an hour after the re-calibration� ... the pilots maneuver the massive bomber to the start of the runway. COMMANDER GRIEVE Everything was a hundred percent routine until we hit a hundred knots . That's when we got the FCS Master Caution. Before I could even push the button, it rescinded itself. INVESTIGATORs delve deeper into the calibration performed that day. They discover that three sensors on the B-2 were providing incorrect air pressure readings� � and that a Master Caution alarm flickered on for a few seconds just before takeoff. But six seconds later� ... the flight computer resolved the sensor discrepancy and cancelled the warning. INVESTIGATORs learn that while the pilots waited to resume their mission, the Spirit of Kansas sat on the tarmac. Weather records show that the night before the accident, a tropical rainstorm settled over the base. Tests confirm that the sensors exposed to the heaviest rainfall became saturated and needed recalibrating. Why did the re-calibrated sensors then produce bad data? A state-of-the-art B-2 bomber stalled on takeoff because of faulty data about its climb angle. US Air Force INVESTIGATORs still can�t explain why that happened, and the pressure is on to find answers. General Carpenter reviews what the pilots told them about the flight. Pitot heat is a system of small heaters connected to each of the plane�s sensors. Just before takeoff, the pilots activate the heaters, so the sensors don't freeze when the plane reaches colder temperatures at higher altitudes. General Carpenter asks an engineer who built the system if the pitot heat could have affected the recalibrated sensors. Re-calibrating the sensors brought the three wet ones in line with the others. But turning on the pitot heat evaporated the moisture, putting the sensors back out of alignment. So then why did the faulty Air Data warning disappear so quickly after it came on? The B-2�s flight computer is constantly receiving four separate data streams from all 24 sensors. If there�s a discrepancy in the data from those streams, the computer is programmed to select any two of the channels to proceed. The flight computer selected a channel that contained incorrect information about the pitch angle from the recalibrated sensors. Twelve seconds later, the bad data caused the B-2 to pitch up abnormally. That steep pitch up caught the Spirit of Kansas crew completely off-guard, leaving them vulnerable to the effects of the faulty data. Within two months, the B-2�s flight computer was reprogrammed to address the fault. There have been no issues with bad data since. As sophisticated as aircraft have become, there are still situations where crucial information is communicated by radio. In those scenarios, a failure to check and re- check that data can result in disaster. Independent Air Flight 1851 cruises above the Atlantic Ocean. There are 137 passengers onboard the Boeing 707. Flight Engineer Jorge Gonzalez checks the weather ahead. He�s a US Air Force veteran, as is Captain Leon James Daugherty. First Officer Sammy Adcock started with Independent Air two weeks ago. The flight from Bergamo, Italy, will refuel at Santa Maria, an island in the remote Azores, before continuing to Punta Cana in the Dominican Republic. The airport at Santa Maria is not a busy one. It has no radar. The crew needs to fly over the 2000-foot Pico Alto mountain to reach the airport. Thirteen minutes from the airport, the pilots ready the plane for landing. ILS, or Instrument Landing System, is a navigation system that provides vertical and horizontal guidance to the runway. As they close in on the island, an alert in the cockpit tells the pilots that they are 500 feet above their selected altitude. But as they enter the cloudbank over the island, disaster strikes. Four-and-a-half miles from Santa Maria airport, Portuguese firefighters and civilians discover what remains of Independent Air flight 1851. All 144 passengers and crew on board are dead. By daybreak, the Portuguese Civil Aviation Authority arrives at the crash site. They are soon joined in the Azores by INVESTIGATORs from the U.S. National Transportation Safety Board. Together, they examine the wreckage pattern. Scars on the ridge offer the first clues. They quickly recognize this incident as a Controlled Flight into Terrain, or CFIT. The minimum sector altitude is at least a thousand feet above all terrain within 25 miles of the airport. The team checks to see if the air traffic controller made an error. The Altitude Alert sounds a warning when the plane approaches a pre-set altitude. INVESTIGATORs discover that the altitude was set to two thousand feet , a thousand below the required altitude of three thousand feet . They hope the cockpit voice recorder will reveal why the first officer input the wrong data into the Altitude Alert. INVESTIGATORs compare the transcripts from the plane and from the tower. But this discovery alone isn�t enough to explain why the plane was so low when it crashed into the mountain. INVESTIGATORs have discovered that critical communications about Flight 1851�s required altitude were missed because of overlapping radio calls. But there�s still another question that worries them. QNH is an air pressure value pilots input so their altimeter can accurately measure the plane�s height. That value can change with weather conditions. INVESTIGATORs calculate the change in altitude between the two different settings. They ask the controller about the two different settings he gave to the pilots. INVESTIGATORs turn to the CVR to see if the pilots caught the controller�s mistake. INVESTIGATORs return to the cockpit voice recording to hear how the pilots briefed each other before approaching the landing. The lack of detail is shocking. INVESTIGATORs conclude that the pilots failed to follow procedures that would have caught the bad data provided by the air traffic controller. When bad data slips into the second-by-second calculations that a pilot makes, the consequences can be tragic. Passengers on board Birgenair Flight 301 have a nine-hour flight to Frankfurt ahead of them. The pilots prepare their Boeing 757 for take-off. Captain Ahmet Erdem is one of Birgenair's most senior pilots. Muhlis Evrenesoglu is the Relief Pilot. The captain�s airspeed should read the same as his first officer�s. But it doesn�t. Shortly after takeoff, the Captain�s airspeed indicator appears to be functioning normally. One minute and thirty seconds into the flight, the crew engages the autopilot. Then, the computer reports a problem. The alert warns that the plane is traveling too fast. Captain Erdem�s airspeed indicator shows the plane travelling at 325 knots , but the first officer�s indicates the plane going much slower. Now, a far more serious warning sounds. This alarm indicates the plane is approaching the maximum speed at which it was designed to fly. CAPTAIN ERDEM decides to do what the alerts tell him to do � slow down. The result is terrifying. Shortly after takeoff, Birgenair Flight 301 is in trouble. The cockpit fills with the ominous sound of the stick shaker. The plane�s Attitude Direction Indicator shows that its nose is pointing dangerously high. Suddenly, the plane rolls hard to the right and begins to dive. Birgenair Flight 301 vanishes from radar. No survivors are found. The Dominican Republic�s Aircraft Accident Investigation Bureau asks the US National Transportation Safety Board to assist in their investigation of the downed Boeing 757. It takes three weeks to recover Flight 301's black boxes. INVESTIGATORs immediately notice something unusual about the flight. Shortly after the autopilot is switched on, the plane�s nose pitches upward. They also see that the indicated airspeed is much higher than it should be. They focus their attention on the sensor that feeds airspeed information to the gauges, the pitot tube. When the plane travels forward, an increase in air pressure inside the pitot tube causes the airspeed indicator's needle to move. But if a pitot tube becomes blocked, it can send faulty readings to the plane's gauges. Regulations state that anytime a plane will be on the ground for an extended period of time, pitot tube covers must be placed on the tubes to prevent blockage, usually by dirt or ice. Records indicate that the plane sat on the tarmac in Puerta Plata for twenty-five days before taking off for Frankfurt. INVESTIGATORs wonder if mechanics neglected to cover the pitot tubes after maintenance. The investigation team concludes that in that time, some sort of blockage developed in the pitot tube on the Captain�s side. A blocked pitot tube could have given the pilots bad data in the form of conflicting air speed readings. But how could that lead to such a disaster? Using information from the black boxes, the NTSB pieces together the flight�s last moments. The data shows that the problems on Birgenair Flight 301 began when the autopilot took over. Is it possible that the flight computer was just as confused about the airspeed as the crew? If so, how did that contribute to the crash? INVESTIGATORs have discovered that Flight 301�s autopilot, sensing that the plane was traveling too fast, raised its nose to reduce speed. But the autopilot is reacting to faulty airspeed information from the Captain�s pitot tube. Moments later, it sends out two different warnings. INVESTIGATORs realize that CAPTAIN ERDEM wrongly concluded that both airspeed indicators were malfunctioning. In fact, his first officer�s gauge was always correct. The plane was actually traveling much too slowly. The autopilot system sends a warning that the plane is traveling too fast. But in reality, it�s slowing down. That�s when CAPTAIN ERDEM makes the gravest error of all. At the plane�s already slow speed, pulling back on the throttles puts the plane on the verge of stalling. The autopilot is programmed to always disconnect when the stick shaker activates. With one warning telling him the plane is flying too fast, and another indicating it�s flying too slow, CAPTAIN ERDEM is overwhelmed. In response to the investigation�s findings, The FAA asks Boeing to change some of those warnings. Those changes include the addition of a new warning, which alerts both pilots when their instruments disagree. In addition, Boeing modifies its planes so that pilots can easily choose which pitot tube the autopilot is using for airspeed readings. More than fourteen hundred Boeing planes worldwide are affected by the new directives. One final question remains What blocked the plane�s pitot tubes and caused the airspeed indicator to malfunction? With Birgenair Flight 301's pitot tubes lost on the ocean floor, INVESTIGATORs look at the area surrounding the airport in Puerta Plata and think they�ve found a likely suspect � the mud dauber wasp. More than ever, aircraft depend on complex flight computers for safe flight. Even the smallest scrap of bad data can prove to be deadly. Grieve realizes they�re heading for the ground. Gregorio Luper�n International Airport, in the Dominican Republic. First Officer Aykut Gergin has fewer than seventy-five hours in the plane. Erdem instructs his first officer to call out when the plane reaches takeoff speed. GARRETT HARENCAK Simply put, it'd be nearly impossible to fly this airplane safely without flight computers. FIRST OFFICER ADCOCK Starting to pass through the layers. CAPTAIN DAUGHERTY I can't keep this damn thing level. GPWS Pull up. NTSB INVESTIGATOR What were they doing so low? CAPTAIN ERDEM My airspeed indicator is not working. Something's wrong here. God! God! PILOT LINK What was that? COMMANDER GRIEVE We gotta get out. REBECCA GRANT If they can't figure out what went wrong, this could be the end of the B-2 bomber program. MARY SCHIAVO You don't just fly with a stick and a rudder and look out the window anymore. TECHNICIAN You�re good to go, sir. PILOT LINK Thank you. COMMANDER GRIEVE Okay. Let�s head home then. PILOT LINK Copy that. GARRETT HARENCAK They were beginning a sixteen-hour continuous flight back to Whiteman Air Force Base, which was our home base. PILOT LINK Tower, Death 5. Start-up is complete. You can activate our flight plan. PILOT LINK Thrust to M-C-T. TONY MONETTI The very first time I flew the B-2, I felt like I was a bird. It was so smooth. COMMANDER GRIEVE One forty-five . Rotate. TONY MONETTI The next thing they know, they�re going straight up. COMMANDER GRIEVE Full power. TONY MONETTI From my fifteen years of flying the B-2, the only time I felt a B-2 shake is in the simulator. COMMANDER GRIEVE We gotta get out. REBECCA GRANT I�m stunned. The B-2 has gone through 19 years and three wars without a crash. This is unheard of. TONY MONETTI We wanted to know what the heck just happened? AIR FORCE ENGINEER You�re never gonna believe this. FLOYD CARPENTER Your first reaction when you see that airplane pitch up is like, what are they doing? INVESTIGATOR CARPENTER Perfect. What about the actuator? Okay. FLOYD CARPENTER The engines were not a problem, the hydraulics weren't a problem, the flight controls were not a problem. REBECCA GRANT It�s a beautiful sunny morning. Why does a bomber pitch its nose up and crash in a fireball on the runway at Guam? FLOYD CARPENTER Something happened to cause this airplane to pitch up. GARRETT HARENCAK Simply put, it'd be nearly impossible to fly this airplane safely without flight computers. INVESTIGATOR CARPENTER Until it stalled. So airspeed, climb angle and altitude are all off. How does that happen on this plane? INVESTIGATOR CARPENTER Let�s see what the pilots can tell us. COMMANDER GRIEVE We started up at 9:15. A few minutes later, Major Link saw the calibration message during start-up. PILOT LINK Hey chief, we�re seeing an air data cal message. GARRETT HARENCAK In the simplest terms, the air data calibration gives the aircraft its orientation to the universe. FLOYD CARPENTER If they get out of balance, it calls for an air data calibration and the pilots call up maintenance. TECHNICIAN Can you put it in Maintenance Mode for me? TECHNICIAN You�re good to go, sir. COMMANDER GRIEVE Pitot heat is on. COMMANDER GRIEVE Clear right. Good to line up. INVESTIGATOR CARPENTER Okay. Go on. PILOT LINK Stop or go? COMMANDER GRIEVE Go. Warning rescinded. TONY MONETTI In that scenario, if I was the pilot in command, I would continue. Why? It's, it's not safety of flight. COMMANDER GRIEVE When we hit one-forty-five , I called for Major Link to rotate. Then it all very quickly went to hell. TECHNICIAN You�re good to go, sir. COMMANDER GRIEVE Thank you. AIR FORCE ENGINEER These three weren't just off by a little. They are way off. COMMANDER GRIEVE 100 knots . FLOYD CARPENTER At that point, we really didn't know how they were related, but we figured they might be. PILOT LINK What was that? COMMANDER GRIEVE FCS Caution. AIR FORCE ENGINEER The re-calibrated sensors started providing faulty air data again. PILOT LINK Stop or go? COMMANDER GRIEVE Go. INVESTIGATOR CARPENTER What is going on with this plane�s sensors? Okay. So, let's start at the top. Why the need to re-calibrate in the first place? INVESTIGATOR CARPENTER Huh. So they got delayed by a day. INVESTIGATOR CARPENTER Okay. So the jet was left outside for 24 hours because of the delay. So what? INVESTIGATOR CARPENTER Tell me a rain storm didn't take down a 2-billion-dollar airplane. INVESTIGATOR CARPENTER See, something just doesn't add up. They did the recalibration. TECHNICIAN You're good to go, sir. INVESTIGATOR CARPENTER But they still ended up with faulty data. AIR FORCE ENGINEER That nearly killed them. COMMANDER GRIEVE Full power. REBECCA GRANT If they can't figure out what went wrong this could be the end of the B-2 bomber program. INVESTIGATOR CARPENTER Okay. So they re-calibrate at 09:34. Nearly an hour later, the Master Caution lights up because of an Air Data issue. So, what happens in those 56 minutes? INVESTIGATOR CARPENTER Routine taxi, they hit the Pitot heat, wait for the timer, and they�re off. COMMANDER GRIEVE Pitot heat is on. COMMANDER GRIEVE Clear right. Good to line up. INVESTIGATOR CARPENTER And then they turn on pitot heat when they get to the runway. FLOYD CARPENTER He was really concerned when he saw and understood, like he only could, that the moisture in the system, and the data that we were putting into it to fix it, could cause such a problem. FLOYD CARPENTER So the data that was put in on the calibration now is invalid again, and the flight computers are now trying to resolve the issue with these sensors. PILOT LINK What was that? COMMANDER GRIEVE FCS Caution. AIR FORCE ENGINEER It�s seconds from takeoff. So it has to make a choice. AIR FORCE ENGINEER It just chose wrong. COMMANDER GRIEVE One-forty-five. Rotate. FLOYD CARPENTER Once they rotated the aircraft on speed, as they thought, and left the ground, they were along for the ride at that point. COMMANDER GRIEVE Full power. FLOYD CARPENTER There�s no way a pilot or a maintainer would understand the system well enough to realize what could have happened when they did that data calibration. REBECCA GRANT Well in the end, safety is everything. It doesn't matter if it's an airliner, a fighter jet, a space plane, or a stealth bomber. FLIGHT ENGINEER GONZALEZ Santa Maria, Independent Air one eight five one, requesting MET report. CAPTAIN DAUGHERTY Let's request descent. FIRST OFFICER ADCOCK Santa Maria Control, Independent Air one eight five one would like to descend. THOMAS DUKE The crew was a balanced crew. They had flown together for about a week or ten days and they were doing fine. JIM KRIEGER There were only three scheduled airline flights per day. It doesn't justify the cost of air traffic control radar. TRAINEE CONTROLLER You�re cleared three thousand feet on QNH one zero two seven. Runway will be one niner. Expect ILS approach, runway one niner. Report reaching 3,000 . JIM KRIEGER The controller is relying solely on position reports from the pilot. So they have to be meticulous about documenting the altitude that the aircraft is at. FRANCISCO CUNHA On that day, the weather in Santa Maria was fine. There was just some cloud cover in the vicinity of Pico Alto. FIRST OFFICER ADCOCK Okay, I'm gonna to go ahead and put the ILS in on my side. CAPTAIN DAUGHERTY Okay. THOMAS DUKE That means that he can fly in clouds until he gets onto final approach. FIRST OFFICER ADCOCK Don't know if we're gonna get visual or not here. Starting to pass through the layers. CAPTAIN DAUGHERTY I can't keep this damn thing level. GPWS Pull up. Pull up. Pull up. FRANCISCO CUNHA The jet hit Pico Alto very near the top of the mountain. The accident site was a chaotic scene. The wreckage was strewn all over the mountain. PAPUAN INVESTIGATOR So this is the flight path. The plane impacts the east side of Pico Alto. NTSB INVESTIGATOR Correct. NTSB INVESTIGATOR All concentrated right here, sending debris over the mountain ridge. NTSB INVESTIGATOR Looks like low angle, high velocity. They must have been flying level. PORTUGUESE INVESTIGATOR CFIT? NTSB INVESTIGATOR It looks like it. NTSB INVESTIGATOR What was the altitude where they hit? PORTUGUESE INVESTIGATOR 1,795 feet . NTSB INVESTIGATOR And Pico Alto? What does the Jeppesen chart show? PORTUGUESE INVESTIGATOR It�s listed as 1,936 feet . NTSB INVESTIGATOR They struck the mountain 140 feet below what was listed on their chart. What were they doing so low? BARRY STRAUCH The possibilities were one, they were... the crew was off course. Two, there was an altitude error. It was our job to find out which of those would explain the accident. NTSB INVESTIGATOR What�s the minimum sector altitude? PORTUGUESE INVESTIGATOR Three thousand feet . NTSB INVESTIGATOR There�s plenty of room. PEDRO MATOS Why did these guys descend so low when they knew by the charts that the minimum altitude was 3,000 feet and there was a mountain there? PORTUGUESE INVESTIGATOR What was the minimum sector altitude you gave them? TRAINEE CONTROLLER Uh 3,000 feet . PORTUGUESE INVESTIGATOR You�re sure? TRAINEE CONTROLLER Yeah. I even made a note of it on my flight strip. PEDRO MATOS He was perfectly calm. He had a normal behaviour. He thought he had done a good job. PORTUGUESE INVESTIGATOR Were they advised to use the ILS? TRAINEE CONTROLLER Yes. TRAINEE CONTROLLER Expect ILS approach, runway one niner. Report reaching 3,000. PEDRO MATOS I couldn't find anything that explains what happened from his part. NTSB INVESTIGATOR Maybe the Altitude Alert survived? PORTUGUESE INVESTIGATOR Let's take a look. BARRY STRAUCH This shocked all of us. We, we just couldn't believe it, how that could happen. TRAINEE CONTROLLER Independent one eight five one, roger. You're cleared to three thousand feet on QNH one zero two seven. FIRST OFFICER ADCOCK Cleared to two thousand . NTSB INVESTIGATOR Did the first officer just say 2,000 ? PORTUGUESE INVESTIGATOR Maybe he heard to three thousand and mistook it for two thousand . NTSB INVESTIGATOR The controller should have corrected him too. But doesn't. Why? PORTUGUESE INVESTIGATOR Hang on a second. The first officer�s read back of two thousand feet isn't in the controller's transcript. NTSB INVESTIGATOR So he never heard it? How is that possible? PORTUGUESE INVESTIGATOR Hang on. NTSB INVESTIGATOR They were talking at the same time. PORTUGUESE INVESTIGATOR Yeah. They cancelled each other out. TRAINEE CONTROLLER You�re cleared to 3,000 feet on QNH one zero two seven. Runway one niner. FIRST OFFICER ADCOCK We�re cleared to 2,000 feet and uh one zero two seven. TRAINEE CONTROLLER Expect ILS approach runway one niner. Report reaching 3,000 . BARRY STRAUCH It was stunning. We were stunned to finally understand how the two transmissions overlapped perfectly to cancel each other out. I was an INVESTIGATOR for over 30 years with the NTSB. I�ve never encountered anything like this before and I never encountered anything like this afterwards. INVESTIGATOR So the controller doesn�t hear it. TRAINEE CONTROLLER Runway one-niner� NTSB INVESTIGATOR Something doesn't line up. The plane�s altimeter alert was incorrectly set to two thousand feet . Even at that altitude, they would have cleared the ridge by some 200 feet . What else affects altitude? PORTUGUESE INVESTIGATOR Qnh. JIM KRIEGER If the altimeter is set to a higher QNH than is actual, the aircraft will actually be lower than what the altimeter is telling the pilots. PORTUGUESE INVESTIGATOR It says here they were given a QNH of 1019 at 1:44 pm. Then they were given a reading of 1027 at 1:56 pm. PORTUGUESE INVESTIGATOR That Qnh brought them at least 200 feet below 2000 . NTSB INVESTIGATOR Right into the mountain. TRAINEE CONTROLLER One zero one nine was on the MET report. PORTUGUESE INVESTIGATOR But twelve minutes later when you gave them the three-thousand-foot clearance , you said QNH one zero two seven. TRAINEE CONTROLLER Sorry. I don't know where I got that second number. PORTUGUESE INVESTIGATOR After the first officer gets the minimum descent altitude wrong, he questions the QNH. FIRST OFFICER ADCOCK Is that what they said? 1027 on the millibars? CAPTAIN DAUGHERTY Yep. NTSB INVESTIGATOR He was right to question it. PORTUGUESE INVESTIGATOR But the captain just dismisses it. Thank you. NTSB INVESTIGATOR And the first officer just accepts it. BARRY STRAUCH Because of the different experience levels, because of the prominence and assertiveness with which the captain said it, it shut off any discussion. PORTUGUESE INVESTIGATOR Makes you wonder what else these guys missed. FIRST OFFICER ADCOCK Altimeters? CAPTAIN DAUGHERTY Set and cross-checked. FIRST OFFICER ADCOCK Set and cross-checked. FLIGHT ENGINEER GONZALEZ Seatbelts and shoulder harness. FIRST OFFICER ADCOCK Secured. We're having fun now. CAPTAIN DAUGHERTY Hey, hey. NTSB INVESTIGATOR That's it? Stop the tape. PORTUGUESE INVESTIGATOR They don't even mention the minimum descent altitude. NTSB INVESTIGATOR Or Pico Alto, here. BARRY STRAUCH Had they done the approach briefing and reviewed the information and articulated the information as required, it�s highly unlikely, in my opinion, that they would have struck the mountain. FIRST OFFICER ADCOCK Starting to pass through the layers. GPWS Pull Up. Terrain. Terrain. Pull up. BARRY STRAUCH The captain is ultimately responsible as the pilot in command, but each crew member failed in that respect. GPWS Pull Up. Pull up. TODD CURTIS One doesn't necessarily completely trust any system or any data resource. The information that one receives, either from one�s senses, or from the instruments of the aircraft, or from outside navigational aids, has to be balanced with one's own experience and judgment. FIRST OFFICER GERGIN Cabin crew, take your seats, ready for take-off. Exterior lights. CAPTAIN ERDEM Checked. CAPTAIN ERDEM Thank you. Ready for takeoff. FIRST OFFICER GERGIN Alpha Lima Whiskey Three Zero One, ready for takeoff. PUERTO PLATA GROUND CONTROL Three Zero One cleared for takeoff, runway zero eight. FIRST OFFICER GERGIN Cleared for takeoff, runway zero eight, three zero one� RELIEF PILOT EVRENESOGLU A good flight. CAPTAIN ERDEM Good flight. FIRST OFFICER GERGIN Good flight. Power set. CAPTAIN ERDEM Okay check. FIRST OFFICER GERGIN Eighty knots . CAPTAIN ERDEM Check. My airspeed indicator�s not working. FIRST OFFICER GERGIN One twenty . CAPTAIN ERDEM Is yours working? FIRST OFFICER GERGIN Yes sir. CAPTAIN ERDEM You tell me. FIRST OFFICER GERGIN V-one. Rotate. CAPTAIN ERDEM Climb thrust. FIRST OFFICER GERGIN Climb thrust. CAPTAIN ERDEM Center autopilot on, please. FIRST OFFICER GERGIN Center autopilot has command. CAPTAIN ERDEM Thank you. CAPTAIN ERDEM Rudder ratio? Mach airspeed trim? FIRST OFFICER GERGIN Yes, trim. CAPTAIN ERDEM Something's wrong here. FIRST OFFICER GERGIN Mine shows only two hundred now and decreasing, sir. CAPTAIN ERDEM Both of them are wrong. FIRST OFFICER GERGIN Now it's three hundred and fifty , yes? CAPTAIN ERDEM Let's take that like this. CAPTAIN ERDEM God! God! CAPTAIN ERDEM God! God! God! JOHN COX It means that the airplane is about to attain a speed so low that it cannot sustain flight. RELIEF PILOT EVRENESOGLU Adi. CAPTAIN ERDEM Thrust levers! Thrust! RELIEF PILOT EVRENESOGLU Pull up! CAPTAIN ERDEM What�s happening? BOB MACINTOSH Um any signal from the recorders? BOB MACINTOSH That flight data recorder was, uh, was our key. BOB MACINTOSH Fifteen degrees pitch, nose up. That seems high. ENMANUEL SOUFFRONT It's almost the maximum. ENMANUEL SOUFFRONT Three hundred and fifty knots . It can't be right. BOB MACINTOSH We started carefully looking at what could cause that kind of thing to happen. ENMANUEL SOUFFRONT I'd like to ask you some questions about the Birgenair plane. ENMANUEL SOUFFRONT Did you put the pitot covers back on them when the maintenance was finished? MAINTENANCE TECH It didn't have any covers with it. We didn't take any off and we didn't put any on. ENMANUEL SOUFFRONT And that's when we discovered that the pitots had not been covered for the twenty-five days that the aircraft remained parked at the international airport in Puerto Plata. BOB MACINTOSH Nobody knows for sure. The evidence is seven thousand feet down in the Atlantic Ocean. BOB MACINTOSH And what we've got for you is a computer... BOB MACINTOSH The captain actually realized that his speed indicator was not working. CAPTAIN ERDEM Is yours working? FIRST OFFICER GERGIN Yes, sir. CAPTAIN ERDEM Center autopilot on, please. FIRST OFFICER GERGIN Autopilot. BOB MACINTOSH Right after the autopilot is engaged, the plane�s nose begins to rise. BOB MACINTOSH It soon rises to 15 degrees. Then it stays there. BOB MACINTOSH The autopilot�s a pretty smart guy. He already knows he's got all the power that he's gonna get for the climb. The only thing for the autopilot to do is raise the nose. BOB MACINTOSH The autopilot gets its data only from the Captain�s pitot tube, the one that was blocked. CAPTAIN ERDEM Rudder ratio? Mach airspeed trim? JOHN COX And the airplane begins picking up warnings, uh, rudder ratio, a variety of things that the airplane is sensing problems. CAPTAIN ERDEM What can we do? BOB MACINTOSH But that needle continued to climb around the, uh, the clock-face until it activated, uh, the, uh, over speed warning. BOB MACINTOSH They're going slow. They think they're going too fast, and confusion has set in. CAPTAIN ERDEM Let's pull the airspeed. Let's see. BOB MACINTOSH You can see that he now pulls back on his throttles. BOB MACINTOSH And that's when he gets the stick shaker. CAPTAIN ERDEM God! God! God! BOB MACINTOSH That Mach airspeed warning horn, combined with the stick shaker was a tremendously mind-boggling experience. JOHN COX They�re in direct opposition of each other and two warnings that you would never expect to get one right behind the other. MARY SCHIAVO You can't fly a modern aircraft without the proper data because you don't just fly with a stick and a rudder and look out the window anymore. Your data is your flight. CAPTAIN ERDEM What�s happening? KELVIN GUERRERO When a Mud Dauber is looking for an area to build its nest, it's looking for a site, a place that's more or less tubular. BOB MACINTOSH They didn't put covers on the pitot tubes. So there was an opportunity to get something like a Mud Dauber uh, in that pitot tube. TODD CURTIS Aircraft and aircraft systems have become much more sophisticated over the years. But even with the most sophisticated aircraft, it's essential and necessary for pilots to know how to deal with those systems, how to understand how they work, how to not use them if they're giving them bad data, and how to manage whatever they have to continue to fly the airplane.