In the Shadow of Watergate: The crash of United Airlines flight 553

Firefighters tackle the flames after the crash of United Airlines flight 553. (Chicago Tribune)

On the 8th of December 1972, a United Airlines Boeing 737 on approach to Chicago’s Midway Airport fell out of the sky and plowed into a residential neighborhood, killing 43 of the 61 people on board along with two on the ground. The last of the survivors had scarcely escaped the burning wreckage when the FBI arrived on the scene. A member of the US House of Representatives had been killed in the crash, but they weren’t there for him: also on the plane was Dorothy Hunt, wife of intelligence officer E. Howard Hunt, one of the agents who organized the burglary of the Democratic National Convention headquarters that triggered the Watergate scandal. In her bag was $10,000 in cash, allegedly hush money bound for the Watergate conspirators. This tied the crash to the ongoing scandal that threatened to topple President Richard Nixon, and speculation immediately ran wild. But the National Transportation Safety Board was already following the evidence down a very different path. The clues in fact suggested that the Watergate ties were a coincidence, and the crash was an accident — one which carried important safety lessons that were at risk of being overshadowed by a baseless conspiracy theory.

N9031U, the 737–200 involved in the accident. (Bob Garrard)

United Airlines flight 553 was a regular service from Washington National Airport in Washington, D.C. to Midway International Airport in Chicago, Illinois. United operated the flight using a first generation Boeing 737–200, which could carry over 100 passengers — but on the 8th of December 1972, it was half empty, with only 55 passengers and six crew on board. In command was Captain Wendell Lewis Whitehouse, who was assisted by First Officer Walter Coble and an extra third pilot, Second Officer Barry Elder.

It was not unusual for politically connected passengers to fly out of Washington National Airport, especially to a major destination like Chicago, but on that day the concentration of such individuals on flight 553 was especially high. Among the passengers was George Collins, a member of the US House of Representatives representing Chicago’s east side. Also on board were several people with connections to the ongoing Watergate Scandal involving President Richard Nixon.

E. Howard Hunt testifies before the Watergate Committee in the U.S. Senate, 1973. (public domain image)

The Watergate Scandal stemmed from two break-ins at the Democratic National Convention headquarters at the Watergate Complex in Washington, D.C. in May and June of 1972. The burglaries were organized by members of President Nixon’s reelection campaign in order to wiretap the telephones of prominent members of the rival Democratic Party, but during the second break-in, the burglars were caught, and it was discovered that the funding for their mission had come from the Committee for the Re-election of the President. Seven people were arrested, including the five burglars, as well as former FBI agent G. Gordon Liddy and former CIA agent E. Howard Hunt, who had organized and overseen the mission. As the seven men faced trial on charges of burglary and conspiracy, President Nixon was privately worried that Hunt and Liddy, who also worked for a secret White House anti-leak task force, would reveal too much about his campaign’s involvement in the Watergate break-ins. It was under these circumstances that E. Howard Hunt’s wife, Dorothy Hunt, boarded flight 553 with $10,000 in cash in her suitcase. Also on board was CBS News reporter Michelle Clark, who was working on a story related to Watergate.

Route of flight 553. (Google)

Flight 553 departed Washington, D.C. at 1:50 p.m. local time and proceeded toward Chicago at 28,000 feet. All was normal until about one and a half hours later, when a light illuminated to inform the pilots that the flight data recorder had failed.

“Recorder go off?” Captain Whitehouse asked.

“Yeah,” said Second Officer Elder.

“See what’s wrong with it, will ya?” Whitehouse ordered.

By this point flight 553 was already on approach into Midway and had been cleared down to 4,000 feet. They were second in line to land behind a light twin turboprop Aero Commander, which was much slower than the 737. In order to keep the two planes far enough apart, the controller asked flight 553 to slow down to 180 knots (333km/h); a little over a minute later, he asked them to slow again, this time to 160 knots. The pilots slowed down by extending the flaps to increase drag, and by reducing engine power.

Now the controller cleared flight 553 to descend to 2,000 feet, and First Officer Coble replied, “Down to two thousand — 553 leaving four.”

But Captain Whitehouse hadn’t actually begun the descent because he and Second Officer Elder were still trying to troubleshoot the flight data recorder. “Christ, I can’t even find the circuit breaker for this,” Elder complained. After locating it, he added, “Don’t know what to say… I get a reaction when I pull the AC.”

“No reaction when you pull the DC though,” said Coble.

“Want me to call maintenance?” Elder asked.

“Call it in,” said Whitehouse. Having remained at 4,000 feet for 35 seconds after being cleared to descend, now he finally initiated the descent to 2,000 feet.

Graph of airspeed and altitude with cockpit conversations overlaid. (NTSB)

However, Captain Whitehouse seemed to be unaware of the extra distance they had traveled during this time. The plane was nearing the outer marker, which signaled the beginning of the final approach phase, and the recommended altitude for crossing the outer marker was 1,500 feet. But Whitehouse had chosen a descent rate of 750 feet per minute, which would be insufficient to reach this altitude by the outer marker.

During the descent, the crew extended the flaps to 30 degrees, resulting in increased lift which momentarily caused the plane to level off. However, the engine power setting was too low to maintain airspeed in level flight in this configuration, causing the plane to slow from 150 knots to 130 before Whitehouse restarted the descent.

Just before 2:26, flight 553 passed over the outer marker at a height of 2,200 feet, 700 feet higher than recommended. Recognizing that they were too high, Captain Whitehouse configured the plane to achieve a descent rate of 1,550 feet per minute, more than the amount recommended for final approach. To accomplish this, he deployed the speed brakes, a set of spoilers which pop up from the wings to increase drag and reduce airspeed. Using the speed brakes while inside the outer marker is rather unusual, and the need to use them showed that the approach was not sufficiently stabilized. Indeed, altitude was not the only area in which the crew was mentally behind their aircraft. It was only now that Whitehouse called for the final descent checklist, which was supposed to be completed before crossing the outer marker.

Speed brakes deployed on a Fokker 70. Speed brakes are often the same control surface as the spoilers, but they represent different use cases: speed brakes in the air, spoilers on the ground. (Arpingstone via Wikimedia)

As Whitehouse and Coble hurried to complete the final descent check, routine tasks like monitoring airspeed fell by the wayside. The pilots rattled off one item after another:

“Flight and nav?”

“Cross checked.”

“Landing gear?”

“Down, three green.”

“Speed brake?”

“Armed,” Coble replied, glancing briefly at the speed brake light. In reality, the speed brakes were fully engaged, not merely armed, but the “speed brakes armed” light would remain illuminated in either of these positions. He apparently didn’t check the actual position of the lever.

Just as they finished the final descent check, Captain Whitehouse caught sight of the ground through the clouds and realized that they were arriving at the minimum descent altitude of 1,000 feet, below which they could not descend without visual contact with the runway. Whitehouse abruptly leveled off at 1,000 feet, but in doing so, he forgot to retract the speed brakes. With the speed brakes still extended while in level flight, the plane began to decelerate rapidly — and it was already traveling at less than 130 knots.

Graph of airspeed and altitude with cockpit conversations overlaid. (NTSB)

Concurrent to these events, the controller was becoming increasingly worried about the separation between flight 553 and the Aero Commander ahead of it. Concerned that the Aero Commander wouldn’t have enough time to clear the runway before the 737 landed behind it, he wanted to order it to shift over from runway 31L to the parallel runway 31R, but it was already too late for the small plane to change course. Instead, he called flight 553 and said, “United 553, execute a missed approach, make a left turn to a heading of one eight zero, climb to two thousand.”

It was at this exact moment that several things happened at once on board flight 553. Just as the controller began his transmission, Captain Whitehouse noticed their decaying airspeed and accelerated the engines from 59% to 75% power. At almost the exact same moment — just as the controller said the word “execute” — the airspeed dropped low enough to trigger the stick shaker, which physically shook the pilots’ control columns to warn them of an impending stall.

Whitehouse and Coble scrambled to respond to this sudden convergence of events. Whitehouse, unaware that he had left the speed brakes extended, apparently concluded that the plane’s configuration was inducing too much drag, so he retracted the flaps from 30 degrees to 15 degrees. This actually had the opposite of the intended effect, reducing the lift generated by the wings and making the situation worse.

“Okay, left turn to one eight zero — left turn okay?” Coble said to the controller.

“Want more flaps?” asked Second Officer Elder.

“Flaps fifteen,” someone said, followed a second later by, “I’m sorry.” At this point, Captain Whitehouse realized his mistake, extended the flaps back to 40 degrees, and raised the landing gear. But neither the flaps, the raised landing gear, nor the extra engine power were sufficient to overcome the drag from the speed brakes, and flight 553 stalled at a height of just 400 feet above the ground.

My sketch of the moment of impact. (Own work)

Massive vibrations rocked the plane as it pitched up steeply and began to fall from the sky. Passengers cried out in terror and the pilots exclaimed in surprise as the plane plummeted tail first toward the densely packed houses below. At such a low altitude, there was no hope of recovery; although Captain Whitehouse finally recognized the problem and retracted the speed brakes, it was already far too late. A split second later, flight 553 clipped a tree and a garage before careening into a house on West 70th Place in Chicago’s West Lawn neighborhood. The house exploded in a hail of flying bricks, and the left wing cleanly sliced half the roof off another. The plane then skidded across the street and slammed headlong into three more houses, which were reduced to rubble by the massive impact. The fuselage broke in two and the forward section all but disintegrated; at the same time a wall split the cockpit down the middle, instantly killing the first officer. As soon as the plane came to a stop, a massive fire erupted amid the tangled debris as spilled jet fuel ignited. Within seconds, towering flames were rising up on both sides of the plane, and those who had survived the crash now faced the threat of burning alive.

A wrecked car lies amid the debris on West 70th Place. (Bettmann)

Most of those seated forward of the wings were killed on impact, but almost everyone in the economy section was still alive when the plane came to a stop. Black smoke and fire immediately poured into the cabin, prompting a mad rush to escape, which was made extremely difficult by dislodged overhead bins and uprooted seats which had been thrown into the aisles. People scrambled over the backs of seats and over each other in a desperate attempt to reach the emergency exits, while the smoke plunged the inside of the plane into near total darkness. In one area, the floor had collapsed; a passenger seated there undid his seat belt and promptly fell through into the cargo hold, from which he managed to escape through a break in the fuselage. Others were not so lucky: many passengers perished inside the burning plane after inhaling toxic gases from the smoke, including carbon monoxide and hydrogen cyanide. Among those who succumbed to smoke inhalation were all the remaining passengers in the first class section, along with Captain Whitehouse, and several people from economy who didn’t make it to the exits in time.

Firefighters work to extract Marguerite McCausland from the wreckage of the cockpit. (Chicago Tribune)

Firefighters and police arrived on the scene within minutes, only to find the plane already almost completely consumed by a raging inferno. Survivors who had staggered out onto the street were loaded into ambulances and rushed to nearby hospitals, while firefighters tackled the massive blaze. The fire was not extinguished until nearly 30 minutes after the crash, by which point rescuers held out little hope that anyone else would be found alive. But in fact, one person was still clinging to life amid the mangled wreckage: flight attendant Marguerite McCausland, who had been seated just behind the cockpit. During the crash, she was thrown partially out of the plane and into a pile of aircraft debris and rubble from a house, which shielded her from the flames. As firefighters combed through what remained of the cockpit, she heard one of them say, “I don’t think anyone is alive in this part of the plane.” Desperate to get their attention, she began to yell and scream from under the debris, attracting the attention of the rescuers, who began a delicate operation to free her. Minutes later, McCausland was pulled to freedom and rushed to hospital in critical condition, the only survivor seated forward of the wings. Despite suffering extensive injuries to every part of her body, she eventually made a full recovery after spending three and a half months in hospital.

An aerial view of the crash site reveals the extent of the destruction. (Chicago Tribune)

Unfortunately, most of those on board flight 553 weren’t so lucky. 43 passengers and crew were dead, including all three pilots, while only 18 escaped with their lives. Rescuers also discovered the bodies of two West Lawn residents who were killed when the plane leveled their house, but more would have died if not for a lucky coincidence: one family whose house was destroyed had been in the basement at the time of the crash, protecting them from the flying debris.

The National Transportation Safety Board was quickly informed of the accident, and within hours a team of investigators arrived in Chicago from Washington, D.C. When they reached the site of the accident, they were surprised to find around 50 agents from the Federal Bureau of Investigation already on the scene interviewing survivors and listening to the air traffic control tapes. The investigators thought this was unusual, but within 24 hours the FBI closed its investigation into the accident and gave the NTSB full control of the crash site and all relevant materials.

A view along the trail of destruction left by flight 553. (Chicago Tribune)

The NTSB was frustrated to find that a mechanical failure had rendered the flight data recorder inoperative just 14 minutes before the crash, but the cockpit voice recorder was working normally and the tape was successfully played back the following day. The recording revealed that flight 553 had stalled at a low altitude, confirming witness reports that the plane fell steeply down while in a nose-high attitude. The question was why — something which would be hard to determine without access to the flight data. Fortunately, there was an alternative: radar data from the control tower had recorded the plane’s ground speed and altitude throughout the approach. Although it was less accurate than FDR data, it promised to provide a basic outline of the airplane’s performance.

The main thing investigators needed to understand was what configuration allowed the stick shaker to activate just 7 seconds after leveling off at 1,000 feet, and stall just 8–10 seconds after that. Based on the airspeeds derived from the radar data, and known aspects of the configuration revealed by the CVR, the NTSB conducted a series of simulator tests and live flight tests to determine which scenarios most closely matched what actually happened to the airplane. They found that the only way to get the airspeed to decay rapidly enough to trigger a stall so quickly was to leave the speed brakes extended after leveling off at 1,000 feet. Although there were no conversations on the CVR about the deployment of the speed brakes, it was considered highly likely that Whitehouse had used them to achieve the descent rate of 1,550 feet per minute after passing the outer marker.

A view of the initial impact area. (Bettmann)

Meanwhile, a separate set of facts was emerging which prompted speculation of an entirely different nature. In the days immediately following the crash, it was revealed that Dorothy Hunt, wife of Watergate conspirator E. Howard Hunt, was killed in the accident, along with reporter Michelle Clark and Representative George Collins. In Hunt’s suitcase were $10,000 in cash, the purpose of which was not initially clear. However, many began to suspect that the Nixon administration was paying Hunt and Liddy to keep quiet in the burglary trial (an accusation which was confirmed with the release of the Oval Office tapes on June 30th, 1973). It seemed possible, even probable, that the $10,000 carried by Dorothy Hunt were intended for this purpose. Was it a coincidence that she and a reporter investigating the scandal both died in the crash? Some thought that it wasn’t.

Smoke rises around the tail of the 737. (Chicago Tribune)

The biggest proponent of conspiracy theories about the crash of flight 553 was Sherman Skolnick, a private investigator from Chicago. He became convinced that the crash was a deliberate act targeting not just Dorothy Hunt but also 11 other people on the plane who he thought were connected to Watergate. By collecting documents and testimony from informants, he developed a convoluted theory involving not just a simple hit by the Nixon administration, but also a competition between oil companies, the mob, secret documents, a robbery on board the plane, and the in-flight cyanide poisoning of Captain Whitehouse. None of these events could be corroborated by witness testimony from any of the 18 survivors. At the center of the theory were allegations that Dorothy Hunt was becoming disturbed by the president’s increasing criminality, and that her husband had enough to “blow Nixon out of the water.” He alleged based on the statements of informants that Hunt actually had $50,000 in cash with her and another $2 million in securities, and that she had been seen speaking to the CBS reporter before boarding the plane. But when he asked to testify at the NTSB’s public hearings into the crash in the summer of 1973, NTSB chairwoman Isabel Burgess denied his request for obvious reasons. In response, Skolnick sued Burgess and called the hearings a “sham and a pretense.” To avoid a lengthy legal dispute, the NTSB eventually reversed course and allowed him to present his findings at the hearing.

Firefighters tackle the blaze in the center fuselage area. (Chicago Tribune)

Although most newspapers refused to touch Skolnick’s story, some smaller ones did, and their summaries of his testimony — while portrayed as credible by the reporters who wrote them — contained so many false statements that Skolnick’s conspiracy theory totally falls apart under the most basic analysis. One such article by the Ann Arbor Sun listed eight points in support of Skolnick’s theory, of which the majority were blatantly false. The article claimed that both black boxes failed mysteriously before the crash (despite the fact that the CVR was working and the transcript is easily available); and that because Midway International Airport was “little used” and “almost deserted,” it was weird that the plane was flying there at all (ignoring the fact that United Airlines had operated to Midway daily since the 1930s without interruption). It further stated that “The crash occurred suddenly which is out of key with the idea that the captain was trying to avoid a collision,” a statement clearly based on a gross misinterpretation of the controller’s request for flight 553 to go around due to inadequate separation from the Aero Commander, which had nothing to do with the accident sequence anyway. It also turned out that the FBI was on scene before the NTSB because the Chicago Police Department had requested their assistance, and they didn’t know Dorothy Hunt was even on the plane until after they had already ruled out foul play, 20 hours after the accident.

Rescuers, police, investigators, and FBI agents were all among those on the scene as night fell. (Chicago Tribune)

Another of Skolnick’s points was that “there was a pinprick in the altimeter, making it malfunction.” While both altimeters showed altitudes that were off by about 100 feet, this was explicable due to the extreme nose up attitude of the aircraft which interrupted airflow into the pitot tubes; this error also was too small to have any bearing on the accident. The article also stated that the instrument landing system was “mysteriously” turned off prior to the flight’s arrival, and that this could have caused the crash, but this was irrelevant because trained pilots are perfectly capable of landing without the ILS. And Skolnick claimed that a Nixon stooge had been appointed Undersecretary of the Department of Transportation and thus had power over the NTSB, but the NTSB is an independent agency and is not under the jurisdiction of the Undersecretary of Transportation. That left only a couple of bits of circumstantial evidence: the identities of those on the plane, some statements from unidentified informants, and a level of cyanide in Captain Whitehouse’s blood that some experts thought was too high to be from smoke inhalation.

Skolnick’s testimony was so riddled with factual errors that observers actually started laughing at him during the hearing. Nevertheless, an embarrassingly large number of people took him seriously, including the hapless author of the article in the Ann Arbor Sun, who wrote that there was “no evidence” for the NTSB’s version of events and called for a new investigation. The article gave off the impression that its author knew next to nothing about airplanes and even less about the crash of flight 553. Readers who similarly lack knowledge about the case might be inclined to think the story carried some actual weight, which has caused the Watergate connection to flourish in conspiracy circles ever since.

Another view of the rescue operation near the cockpit. (Chicago Area Fire Departments)

A few weeks after Skolnick’s testimony, the NTSB released its final report, which outlined the whole sequence of events in painstaking detail. Although the crash unfolded in just a few seconds, the stage had been set for a problem much earlier in the approach. This was a classic case of a pilot falling behind his airplane. The trouble started when the pilots became distracted trying to troubleshoot the flight data recorder, which delayed all future tasks, while the plane continued to close in on the airport. As a result, they began their descent from 4,000 feet too late, necessitating the use of the speed brakes to descend faster and make up for lost time. Now they passed over the outer marker without having finished the final descent check, so they rushed through it, distracting them from actively monitoring their airspeed and altitude. Due to the hurried nature of the events, by the time he leveled off Captain Whitehouse had forgotten that the speed brakes were still extended. Flying level with the speed brakes extended resulted in rapid airspeed decay. The stick shaker stall warning then went off before Whitehouse even had a chance to look at his airspeed reading, and he reacted with solutions that would have worked with the speed brakes stowed (such as increasing thrust to 75% and retracting the flaps and landing gear to reduce drag), but these measures were insufficient with the speed brakes extended. Once the plane stalled, there wasn’t enough altitude to recover.

An open emergency exit reveals how most of the surviving passengers got out of the burning plane. (Chicago Area Fire Departments)

All of these errors could be summarized under what the NTSB called inadequate “flight management.” A pilot must remain aware of what his or her aircraft is doing at all times in order to ensure that airspeed remains within acceptable values and altitude targets are met in a timely manner. On flight 553, the pilots allowed the airspeed to develop a mind of its own and assumed it wouldn’t drop too low, instead of carefully tracking it and actively intervening to ensure it stayed high enough.

In order to ensure that pilots wouldn’t make the same mistakes in the future, the NTSB recommended that pilots be taught that the stick shaker could activate at a higher airspeed if the speed brakes are extended, and that the FAA issue an advisory bulletin informing pilots of the risks of using the speed brakes improperly. The NTSB also called for better standards for crew communication, something which became especially pertinent just three weeks after the crash of flight 553, when Eastern Airlines flight 401 descended into the Everglades and crashed while the crewmembers tried to troubleshoot a burnt out landing gear light. Based on these two accidents, and another accident which occurred at Chicago-O’Hare earlier in 1972, the NTSB further recommended that “fasten shoulder harnesses” be added to the before landing checklist (noting that Captain Whitehouse might have been able to escape the plane if not for debilitating injuries sustained due to not wearing a seat belt), and that airplanes have illuminated exit signs that can be seen through dense smoke.

Firefighters stand atop the 737’s ruined tail section. (Chicago Tribune)

While the crash of flight 553 is not particularly well-known today, the outcome of the Watergate scandal has ensured that it still gets mentioned from time to time in the discussion surrounding the infamous conspiracy. After the release of tapes proving that President Nixon tried to cover up his campaign’s involvement with the Watergate break-ins, Nixon resigned from the presidency under threat of removal from office by the United States Senate. While it was indeed proven that officials connected to Nixon were sending “hush money” to E. Howard Hunt and G. Gordon Liddy, it was never conclusively shown that the $10,000 in Dorothy Hunt’s baggage were intended for this purpose, and despite the release of thousands of documents related to Watergate, no further evidence has come to light in the 48 years since the crash that would connect it to the Watergate scandal. Despite being commonly known as the “Watergate plane crash,” the presence of Mrs. Hunt on board United Airlines flight 553 turned out to be nothing more than a tragic coincidence. One of the lessons of the crash is not a traditional safety lesson, but a social one: that not everything is a conspiracy. If the crash had been a work of fiction, calling it a coincidence would have been bad writing, but the real world isn’t a novel. At the end of the day, the truth usually makes less sense than fiction.

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Analyzer of plane crashes and author of upcoming book (soon™). Contact me via @Admiral_Cloudberg on Reddit or by email at kylanddempsey@gmail.com.