Grounded: 4 Other Aircraft Plagued by Technical Troubles Like the 737 Max
Grounded: 4 Other Aircraft Plagued by Technical Troubles Like the 737 Max - The Infamous DC-10 and its Cargo Door Defects
The DC-10 airliner, produced by McDonnell Douglas in the 1970s, was plagued by a major design flaw with its cargo door that led to several deadly accidents. This infamous issue underscores the critical importance of rigorous design testing and safety oversight when bringing new aircraft to market.
In 1972, shortly after the DC-10 entered service, a door blew open mid-flight on an American Airlines flight, causing explosive decompression that led to a crash landing that killed all 45 people on board. Investigators discovered that the cargo door design allowed it to be improperly latched, such that pressurization during flight could pop it open. McDonnell Douglas redesigned the latching mechanism, but the problem recurred in 1974 on a Turkish Airlines DC-10 that crashed near Paris, killing 346 people.
Again, the issue was inadequate latching that allowed the door to blow out due to pressurization forces. The cargo doors were just one of this aircraft’s design deficiencies; it also had a history of wing and engine failures. By 1983, the DC-10 had been involved in 56 accidents that claimed nearly 1,600 lives.
The DC-10 debacle underscored the need for extensive testing of all aircraft systems before certification, not just individual components. Pressurization forces and complex interactions between structures, controls and components require holistic design reviews. Strong oversight by regulators is also essential, though the DC-10 was certified despite known issues and objections by the FAA’s own engineers.
What else is in this post?
- Grounded: 4 Other Aircraft Plagued by Technical Troubles Like the 737 Max - The Infamous DC-10 and its Cargo Door Defects
- Grounded: 4 Other Aircraft Plagued by Technical Troubles Like the 737 Max - Airbus A320s - Fly-by-Wire Flaws Lead to Fatal Crashes
- Grounded: 4 Other Aircraft Plagued by Technical Troubles Like the 737 Max - Why Wiring Issues Plagued Early 787 Dreamliners
- Grounded: 4 Other Aircraft Plagued by Technical Troubles Like the 737 Max - The Comet - How Metal Fatigue Doomed the First Jet Airliner
- Grounded: 4 Other Aircraft Plagued by Technical Troubles Like the 737 Max - ATR 72 Turboprops - Icing Problems Lead to Loss of Control
- Grounded: 4 Other Aircraft Plagued by Technical Troubles Like the 737 Max - MD-80s - The Notoriously Unreliable Flaps and Slats
- Grounded: 4 Other Aircraft Plagued by Technical Troubles Like the 737 Max - The Mitsubishi Regional Jet and its Faulty Braking System
- Grounded: 4 Other Aircraft Plagued by Technical Troubles Like the 737 Max - Will the Embraer E-Jet Suffer a Similar Fate?
Grounded: 4 Other Aircraft Plagued by Technical Troubles Like the 737 Max - Airbus A320s - Fly-by-Wire Flaws Lead to Fatal Crashes
The Airbus A320, which entered service in the late 1980s, represented a major advancement in commercial aviation with its introduction of digital fly-by-wire flight controls. However, this new technology was not without risks, as tragically demonstrated by several deadly A320 crashes in the early 1990s.
On June 26, 1988, an Air France A320 crashed while demonstrating the jet at an airshow near Mulhouse-Habsheim airport in France. While flying low and slow, the A320 suddenly banked hard right and slammed into trees beyond the runway. Three passengers were killed and 50 injured. Investigators found that the fly-by-wire system allowed the pilot to put the plane into an aerodynamically unstable configuration from which it could not recover.
This flaw in the fly-by-wire programming contributed to another disaster in January 1990, when an Indian Airlines A320 crashed short of the runway in Bangalore after encountering windshear on approach. It lost speed stability in the disturbed air and the pilots lost control as the computers could not stabilize the jet. 92 of the 146 people aboard perished.
A subsequent crash in 1994 cemented the early A320's reputation as unsafe. A Thai Airways flight stalled and crashed near the airport in Surat Thani, Thailand, killing 45 of the 146 people on board. Again, the fly-by-wire system allowed the aircraft to get into an unrecoverable stall condition from which the pilots could not regain control.
These incidents showed that while fly-by-wire brought many benefits, like smoother handling, it also posed risks if pilots could too easily put the plane into configurations the automated systems could not handle. More programming safeguards and training for pilots on the unique characteristics of fly-by-wire jets were needed.
Grounded: 4 Other Aircraft Plagued by Technical Troubles Like the 737 Max - Why Wiring Issues Plagued Early 787 Dreamliners
The Boeing 787 Dreamliner entered service in 2011 as the company’s most advanced commercial jet ever. Using powerful new engines, advanced composite materials, and electrical systems, the Dreamliner promised airlines major fuel savings and passengers a smoother, more comfortable flight experience. However, early examples of the jet suffered from numerous technical issues, especially involving the electrical wiring that is so critical for any fly-by-wire aircraft.
Unlike traditional aviation wiring that uses mechanical linkages for flight controls, the 787 relies entirely on electronic signals sent through an expansive wiring system. With over 60 miles of wiring snaking through the plane, the Dreamliner posed an immense challenge for Boeing engineers. They adopted new automated manufacturing techniques to improve consistency in the wiring harnesses.
Unfortunately, once the first Dreamliners rolled out, myriad wiring problems appeared. Inspections found metal shavings, foreign debris and crimping defects that could chafe wires or cause short circuits. One area of particular concern was the emergency beacon wiring, which was susceptible to failure that could trigger fire warnings and require an emergency landing.
The worst nightmare came true in January 2013, when smoke filled the cabin of an All Nippon Airways 787 in mid-flight due to an overheated battery. After an emergency landing, the ANA and also a Japan Airlines 787 were voluntarily grounded. Over the next few months, Boeing scrambled to figure out what went wrong. They discovered manufacturing defects had led to uncontained battery cell failures.
Beyond batteries, Boeing found wiring quality defects in about half of the Dreamliners already produced. They had to implement enhanced inspections and rope in experts to audit the wiring manufacturing process. Over the next few years, Boeing gradually improved wiring reliability by tightening quality control and documentation.
Grounded: 4 Other Aircraft Plagued by Technical Troubles Like the 737 Max - The Comet - How Metal Fatigue Doomed the First Jet Airliner
The de Havilland Comet holds the distinction of being the world's first commercial jet airliner. Introduced in 1952, the pioneering British jet promised a revolution in air travel, carrying 36 passengers at speeds and altitudes far greater than preceding piston-engine aircraft. However, within two years of entering service, three Comet crashes with no survivors shattered confidence in the aircraft and revealed a fundamental flaw in its design.
The root cause was metal fatigue. Pressurized flight places immense cyclic stress on an aircraft’s fuselage, with each pressurization cycle slightly weakening metal structures. For conventional airliners of that era, metal fatigue resulted in cracks appearing over thousands of flight hours. But the Comet, with its unprecedented combination of pressurization and high cruise speeds at up to 40,000 feet, accumulated metal fatigue at a dangerously accelerated rate. Squared windows and shoddily-executed riveting further exacerbated stress points.
The result was catastrophic. In January 1954, a Comet broke up in mid-air and crashed into the Mediterranean Sea off Italy, killing all 35 on board. With wreckage lying on the seafloor, no definitive cause could be identified. Then in April 1954, a Comet en route from Rome to Cairo suffered an explosive decompression at altitude and crashed into the sea near Naples, killing all 21 passengers and crew. Investigators now suspected a structural failure related to pressurization cycles.
The nail in the coffin came just three months later. Another Comet exploded and plunged into the ocean off Greece with similar loss of life. A recovery effort retrieved substantial wreckage, enabling investigators to finally pinpoint the problem: metal fatigue cracking around the corner rivets of the automatic direction finder window in the top fuselage. Each successive pressurization cycle propagated the cracks until they linked up, compromising the structural integrity of the cabin.
Grounded: 4 Other Aircraft Plagued by Technical Troubles Like the 737 Max - ATR 72 Turboprops - Icing Problems Lead to Loss of Control
The ATR 72 is a widely used regional airliner produced by a joint venture between French aerospace firm Aerospatiale and Italian aviation company Aeritalia. This 70-seat turboprop first flew in 1988 and over 500 have been built since then. While generally considered a reliable aircraft, the ATR 72 has suffered from occasional issues with airframe icing that can critically impair controllability.
On October 31, 1994, American Eagle Flight 4184 was approaching Chicago O’Hare when it encountered severe icing conditions. Ice built up rapidly on the ATR 72’s wings and tailplane, increasing drag and decreasing lift. The pilots struggled to maintain control as the autopilot disengaged and the plane rolled violently back and forth up to 45 degrees. After a series of rapid climbs and descents, the ATR 72 stalled and dove inverted into a field, killing all 68 aboard.
Investigators found that ice accumulation on the upper surface of the wings impaired airflow over the ailerons, rendering roll control ineffective. Similar ice accumulation on the horizontal tailplane made the aircraft prone to stall at lower angles of attack. Subsequent research focused on the ATR 72’s unusual susceptibility to corrosion and deformation of the leading edges and underside of wings. This asymmetric degradation of lift worsened the effects of icing.
Another icing incident in December 1994 similarly led to loss of control when ice buildup caused a restriction in the elevator and aileron controls. And in 1995, Poste Air had its elevator limit unit freeze due to internal hydraulic icing issues, triggering wild pitch oscillations on approach that seriously injured two crew members.
These experiences showed that aviation regulators needed to strengthen requirements for how manufacturers demonstrate safe operability in all foreseeable icing conditions. ATR modified the ATR 72’s deicing boots and added aerodynamic tail strakes to make it less vulnerable to aerodynamic imbalances from icing across the wings and tailplane. They also increased the minimum airspeed margins to improve controllability when flying in icing environments.
Grounded: 4 Other Aircraft Plagued by Technical Troubles Like the 737 Max - MD-80s - The Notoriously Unreliable Flaps and Slats
The McDonnell Douglas MD-80 series airliners entered service in the 1980s as an upgrade to the earlier DC-9. More than 1,100 of these single-aisle jets were built before production ended in 1999. While generally a reliable aircraft, early model MD-80s were plagued by issues with the movable panels on the wings called flaps and slats that allow the wings to generate more lift at slower speeds.
During takeoff and landing, the MD-80's wing flaps extend rearward and slats slide forward to increase wing area and curvature, providing the lift needed at slower airspeeds. But on early MD-80s, the slat actuators were prone to jamming and imbalance, while flap actuators experienced excessive wear that affected their synchronization. The result - asymmetrical slat or flap positions that created unsafe roll or pitch forces during critical phases of flight.
One early incident in 1987 saw a newly delivered MD-87 nearly crash during flight testing when the slats froze in an asymmetric position shortly after takeoff. The test pilots were able to regain control after desperately working to overcome the resulting roll. And in 1991, Northwest Airlines Flight 1482 crashed during landing in Detroit after the slats became asymmetric, sending the MD-82 careening wing-first into the ground at a steep angle. Only one passenger survived out of the 149 people aboard.
The FAA ordered modifications to the slat actuation mechanisms after these experiences. But flap problems persisted, and between 1991 and 1999 there were dozens of incidents and several accidents related to flap asymetrics or failures to fully extend on landing. The worst occurred in Little Rock in 1999 when the right wing flaps of American Airlines Flight 1420 only extended to 15 degrees instead of the required 40 degrees. The MD-82 skidded off the runway killing 11 and injuring over 100 people.
Grounded: 4 Other Aircraft Plagued by Technical Troubles Like the 737 Max - The Mitsubishi Regional Jet and its Faulty Braking System
When Mitsubishi Aircraft Corporation set out to build a next-generation regional jet, they aimed to deliver best-in-class fuel efficiency, cabin comfort, and reliability. However, achieving this vision has proven elusive due to serious issues with the aircraft’s braking system.
The Mitsubishi Regional Jet (MRJ), which first flew in 2015, utilizes high-tech carbon brakes produced by Meggitt. While carbon brakes offered reduced maintenance costs and weight savings versus steel, they’ve been plagued by severe overheating that causes damaged wheels and brake assemblies.
During flight testing, the MRJ’s brakes have frequently overheated after high-energy stops, such as aborted takeoffs or maximum braking landings. Temperatures have spiked above the certification limit of 3000°F, damaging brake rotors and requiring extensive repairs. In once instance, an MRJ wheel caught fire after landing.
The fundamental issue is that the brake system lacks sufficient thermal capacity for the MRJ’s weight and typical usage. The system was originally designed based on the lighter Mitsubishi MU-300 business jet. While the MRJ has over 50% greater takeoff weight, the brake system hardware remained unchanged.
Mitsubishi Aircraft has worked extensively with Meggitt to implement software tweaks like updated antiskid brake control logic and reduced braking pressures on landing. But these band-aids haven’t resolved the underlying mismatch between the brake components and the aircraft’s braking energy requirements.
More robust changes are needed. Mitsubishi plans to swap in wheels and brake assemblies from the larger Mitsubishi SpaceJet regional jet family, which uses similar but more capable carbon brakes. But this hardware integration remains ongoing, delaying MRJ certification targeted for mid-2025.
Once in service, the MRJ’s braking issues pose an ongoing maintenance headache for operators. Thermal damage necessitates frequent brake rotor replacement, creating logistical challenges and parts shortages. The costs and delays promise to be a long-term thorn in the side of MRJ customers.
Grounded: 4 Other Aircraft Plagued by Technical Troubles Like the 737 Max - Will the Embraer E-Jet Suffer a Similar Fate?
The travails of the 737 MAX have cast scrutiny on aircraft manufacturers and regulators worldwide. Another popular narrow-body jet, the Embraer E-Jet series, now faces questions about its safety and oversight. As the first clean-sheet regional jet design, early E-Jets promised major efficiency gains. But with hundreds delivered and more on order, can Embraer avoid the pitfalls plaguing the MAX?
When first conceived in the late 1990s, Embraer aimed to leapfrog bulky earlier regional jets by fuse cutting-edge aerodynamics and engines. New swept wings and a T-tail design maximized performance and fuel efficiency. Early models packed a powerful punch, able to operate profitably on routes other jets couldn’t touch.
Yet engineering novel systems often uncovers flaws only revealed in service. Both the original E170/E175 and second-generation E190/E195 models suffered teething issues. Icing disabled pitot tubes, lightning struck vital electronics, and software glitches triggered spurious cockpit warnings. Yet unlike the MAX, these gremlins didn’t cause crashes. Pilot training and experience prevented minor issues escalating into major mishaps.
Still, Brazil’s aviation regulators drew criticism for lax oversight of Embraer, their shining national aerospace champion. Approvals appeared rushed amid pressure to compete with Bombardier and support Brazilian jobs. Despite Embraer’s sterling reputation, regulators should arm themselves with sufficient technical expertise to thoroughly evaluate all systems.
Another concern is Embraer’s 2018 sale of its commercial aviation division to Boeing, including the E-Jet program. Boeing hungered after Embraer’s engineering talent and foothold in the regional jet segment. But the merger places the E-Jet under Boeing’s umbrella, a company whose culture has dangerously prioritized schedule over safety.
Yet Embraer veterans insist their rigorous design principles will prevail. Engineers in Brazil retain substantial autonomy to apply lessons learned improving E-Jet models over 20+ years and 500,000 flight hours. With an enviable dispatch reliability record, they trust their “fly-by-wire” flight controls and software safeguards will prevent any MAX-style debacle.
Still, the mergers may complicate oversight as regulators juggle responsibilities. Brazil understandably wants to continue managing Embraer’s engineering hub. But the FAA maintains ultimate authority for aircraft operated by U.S. carriers. As the E190-E2 rolls out, coordination and transparency between national regulators will prove vital to avoiding gaps or oversights.