VT ILR Tail Strike, Jan 2, 2023, Kolkata.

Author: Lynn Frederick Dsouza

Email: [email protected]

IndiGo flight 6E1859, an Airbus A321neo, experienced a tailstrike during landing at Kolkata-Netaji Subhas Chandra Bose International Airport (CCU). The tail sustained major scrapes. The aircraft took off from Dhaka at 10:42 UTC.

Aircraft Model: Airbus A321-252NX

Registration: VT-ILR

Year of Manufacture: 2021

Engine Type: CFMI CFM LEAP-1A30

Route: Dhaka (DAC) → Kolkata (CCU)

Phase of Incident: Landing

Understanding the Tail Strike Incident: A Deep Dive into Flight Parameters and Critical Moments

In aviation, one of the most critical moments during a flight is the landing. While pilots aim for smooth touchdowns, the smallest misjudgment or reaction can lead to catastrophic events, such as a tail strike. This article breaks down a tail strike incident using data to enhance understanding of the key events that led to the strike, highlighting the importance of control inputs, aircraft behavior, and the activation of safety systems.

1. Sequence of Events: A Timeline of the Incident

The critical events leading to the tail strike. Here’s how it unfolded:

Stable Approach: The aircraft was on a stable approach until 40 feet above the runway.

Pitch-up Input: The First Officer (FO) initiated a pitch-up input below 40 feet, which continued even as the aircraft approached the runway.

Touchdown and Bounce: Upon the first touchdown, there was a slight bounce.

Pitch Input and Tail Strike: The FO continued their pitch-up input, leading to a rapid increase in the pitch angle. A “PITCH PITCH” warning was triggered by the Tail Strike Prevention System (TSPS), but it was ignored. The pitch angle reached 10.7°, causing the tail strike.

Delayed Nose Wheel Touchdown: The nose wheel touched down six seconds after the main gear, contributing to the severity of the incident.

This underscores how each input and response led to the critical outcome. The flow highlights how small, seemingly insignificant actions compounded to lead to a dangerous tail strike.

2. Flight Parameters: The Data Behind the Incident

The visualization focuses on the flight parameters, including radio altitude (RA), pitch angle, and pitch input from the First Officer. This line chart provides a clearer view of how the aircraft’s behavior and control inputs evolved during the critical moments of the approach.

In this chart, we can observe the relationship between the aircraft’s radio altitude, pitch angle, and the First Officer's input:

Pitch Input Dynamics: The FO’s pitch input began at -6.2° and sharply increased, reaching -18° by 11:20:45 UTC.

Pitch Angle Surge: Following the bounce, the pitch angle surged from 5.7° to 10.7°, signaling a critical increase that ultimately led to the tail strike.

Altitude Decline: Radio altitude (RA) steadily decreased as the aircraft neared touchdown, with RA at 0 feet at the moment of tail strike.

This data visualization reveals the dramatic shift in pitch and altitude during the final seconds of the approach. The line representing the FO’s pitch input shows how the aggressive controls exacerbated the aircraft's attitude, while the altitude line confirms the aircraft's descent to the runway.

Key Insights and Implications

Aggressive Pitch Inputs: The FO’s continuous, aggressive pitch inputs began below 40 feet and contributed directly to the tail strike. At the time of touchdown, the aircraft’s pitch angle had already reached 5.7°, a critical level that required careful management.

Failure to Act on Safety Warnings: The Tail Strike Prevention System (TSPS) triggered a “PITCH PITCH” warning when the pitch angle became hazardous. Unfortunately, this was ignored by the FO, leading to the tail strike.

Delayed Nose Wheel Touchdown: The nose wheel’s delayed touchdown, coming six seconds after the main gear, worsened the situation and contributed to the tail strike's severity.

The Need for Pilot Training and Automation Integration

This analysis highlights the interplay between human control inputs, aircraft behavior, and automated safety systems. The key takeaway is that pilot awareness and timely corrective actions are essential in preventing such incidents. Automation, while useful, must be integrated with real-time decision-making by pilots to prevent disregarding critical warnings and avoid dangerous outcomes.

For more information please contact: Lynn Frederick Dsouza, Founder & Director - ESPIRIDI, Email: [email protected] or visit espiridi.com