Why Can't Jet Airplanes at O'Hare Land at 4 or 5 Instead of 3 Degrees? Exploring the Impact of Glide Angle on Noise and Safety

Introduction

O'Hare International Airport in Chicago is a major hub for both commercial and connecting flights. The constant noise and low flight altitudes over the surrounding areas have become a source of frustration for many residents. The common approach has been a 'slope' of 3 degrees, but some suggest that 4 or 5 degrees could be used instead. However, the effectiveness of glide angle in reducing noise levels is often misunderstood. This article aims to shed light on the proper approach and delve deeper into the reasons behind the current landing protocols at O'Hare.

The Role of Glide Angle in Airplane Landings

Glide angle refers to the descent angle of a jet airplane during the final approach to a runway. The commonly used glide angle in civil aviation is 3 degrees, as dictated by various safety guidelines and procedures that have been in place for decades. A 3-degree glide angle is optimal for both civil and military aircraft, balancing the need for safety and efficiency.

Some argue that changing to a 4 or 5-degree glide angle could reduce noise levels, but this is a misconception. The glide angle itself does not significantly impact the noise levels during thrust reversal and landing. Instead, the key factor is the thrust reversers and the repositioning of landing gear, which create the majority of noise upon landing.

Changing the glide angle from 3 to 4 or 5 degrees would require extensive re-trainings for pilots and significant changes in approach speeds and procedures. While these modifications might theoretically be possible, the practical challenges and costs involved make it unlikely to be implemented.

The Historical Context and Safety Considerations

The glide angle of 3 degrees has a long-standing history in aviation, dating back to the safety investigations following tragic incidents like the 1965 crash of United Airlines Flight 227 in Salt Lake City.

On November 11, 1965, United Airlines Flight 227, a 727-100, crashed on landing at Salt Lake City International Airport due to the captain's decision to approach the airport too steeply. This accident led to a review of safe descent rates and may have contributed to the current standard of 3-degree glide angle.

The crash highlighted the dangers of too steep a descent and emphasized the importance of maintaining a proper and safe glide angle during landing. This is why, even when dealing with the constant noise and low altitudes at O'Hare, pilots are trained to follow established guidelines for safety reasons.

Personal Experiences and Observations

Some individuals have shared their personal experiences with the noise levels at O'Hare. For instance, a former resident who flew into Salt Lake City instead of visiting the Isle of White reported that the noise was not as pronounced as they had anticipated. The individual, who flew frequently from Salt Lake to various destinations, observed no significant difference in noise levels in the Bensenville, Wood Dale, and Bloomingdale areas.

Despite the noise complaints, the residents of these areas recognize the importance of maintaining safety and adhere to the standard 3-degree glide angle. The noise associated with thrust reversal and landing gear repositioning is a reality that cannot be easily mitigated by changing the glide angle.

Furthermore, the safety of passengers and crew is paramount. These factors, along with the complexity of retraining pilots and adjusting procedures, make any drastic changes to the glide angle highly improbable.

Conclusion

The standard 3-degree glide angle for jet airplane landings at O'Hare International Airport is not a choice made lightly. It is based on extensive research, safety guidelines, and the practical considerations of pilot training and procedure adjustments. While the noise and low flight altitude are understandable concerns for residents, the effectiveness of a 4 or 5-degree glide angle in reducing these issues is minimal, and the potential risks and logistical challenges make it an impractical solution.

Residents and aviation enthusiasts alike should understand the importance of safety measures and the importance of following established protocols to ensure the well-being of all those involved in air travel.