TRICHY (Tamil Nadu), Aug 22: An IndiGo flight from Trichy to Singapore carrying
127 passengers returned to Trichy international airport around 9 pm Friday due
to a technical glitch. The flight had departed at 6:40 pm.
After circling for nearly two and a half hours to burn fuel load, the aircraft
landed safely at Trichur. The airport had made preparations for a safe landing.
An alternative flight was arranged to take the passengers to Singapore.
Where did A321 suffer tail strike
GORAKHPUR (Uttar Pradesh): An IndiGo flight 6E 2381 operating aircraft
Airbus A321 from Delhi suffered a fuselage scrape (tail strike) during attempted
landing at Gorakhpur airport, it is learnt. All passengers and crew were safe.
The aircraft has been grounded for inspection.
Instead of committing to land with uncertainty, the pilots initiated a go-around
for running the checklists, reports said. The aircraft landed on the second
time without incident. It can only be inducted that there was a tail strike
in the first attempt. But not a word of clarification either in media reports
or the airline statement.
Engineers found scratches near the Auxiliary Power Unit (APU) inlet/tail cone,
confirming the fuselage scrape. Reports are conflicting about where did it happen.
The incident took place on Wednesday. The flight had aborted its first attempt
at landing, and after doing a go-around, landed successfully in the second attempt.
The tail impact was discovered by ground engineers later.
A technical report: When an aircraft suffers a tail strike during a
touchdown or an unstable flare, standard operating procedures dictate that the
crew must immediately abort the landing, initiate a go-around, and climb back
to a safe altitude to stabilize the plane and re-assess the aircraft's systems
before attempting a final landing.
What possibly happened was that during the first touchdown or flare sequence,
the aircraft's attitude became too high, causing the rear underbelly near the
APU inlet to scrape the runway.
Rather than forcing the plane to stay on the ground after an unstable touchdown,
the flight crew executed a standard precautionary go-around, it is understood.
Because the impact occurred entirely at the rear underside, the cockpit instruments
would not immediately show physical damage. The pilots repositioned the aircraft
normally, landed safely, and the scratch marks were only discovered later during
the routine post-flight engineering walk-around.
When landing gear is there how can the belly scrape?: An aircraft's
belly can scrape the runway despite the landing gear being down due to the extreme
pitch angle (nose-up position) of the plane during landing.
If the pilots pull the nose up too high while the aircraft is close to the
ground, the long fuselage acts like a see-saw pivot over the main landing gear,
causing the tail to strike the runway.
Why Airbus A321 is particularly vulnerable
Longer fuselage: The Airbus A321 is seven metres longer than the standard
A320, but it uses the exact same landing gear height. This leaves a much smaller
clearance gap between the tail and the grouind.
Critical tail strike angle: At touchdown, an A321 will suffer a tail
strike if its pitch angle reaches just 9.5 to 11 degrees (depending on how much
the landing gear struts are compressed). By comparison, the shorter A320 can
handle up to 13.5 degrees of pitch.
The pivot effect: The main landing gear acts as a fulcrum. When the
nose rises, the tail lowers. Because the tail extends far behind the wheels,
even a tiny increase in the nose-up angle causes the tail to swing downward
rapidly and hit the tarmac.
Common triggers for a tail strike
Unstable approach: Sudden wind gusts or wind shear can drop the aircraft's
lift, prompting the pilot to pull back aggressively on the controls to avoid
a hard landing.
Early or rapid flare: Pulling the nose up too early or too quickly
right before touchdown causes the aircraft to pitch up past its safe limits
before the main wheels can firmly settle.
Bouncing on touchdown: If the aircraft bounces off the runway, pilots
sometimes instinctively pull back on the stick to cushion the second touchdown,
accidentally driving the tail into the ground.
A321 specifications: Recently Airbus had amended its landing flare guidelines
to initiate the procedure at 40 feet instead of usual 30 for others as a precaution
for its longer fuselage A321 aircraft. A321 tail strikes are very frequent.
Aviation experts say that the A321’s extended fuselage increases susceptibility
to tail strikes. While such incidents are classified as minor, they highlight
the precision required in approach and flare techniques, especially on busy
domestic routes. Taxiway misjudgments by pilots are more common with A321 than
in shorter A320s.
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