Probable airframe issue with Airbus A320neo pose another woe in the sky4 min read . Updated: 18 Sep 2019, 10:18 PM IST
- French aerospace major Airbus SE has identified a problem with the centre of gravity envelope of A320neo planes
- A DGCA official said it is a potential problem with the airframe, not an engine issue
New Delhi: Indian carriers operating Airbus A320 Neo family planes, including IndiGo, GoAir, Air India and Vistara, will now have to significantly reduce their cargo load as these planes, like the grounded Boeing 737 Max planes, could nosedive due to pitch controllability issues.
Indian civil aviation regulator Directorate General of Civil Aviation (DGCA), which will not issue its own Airworthiness Directive (AD) to airlines in this regard, has asked Indian operators of Airbus A320 Neo family planes, including A32 Neo, to follow a 31 July directive by European civil aviation regulator, European Union Aviation Safety Agency (EASA).
The EASA directed airlines operating similar planes to limit center of gravity envelope of the aircraft by limiting cargo intake inside the plane so that this problem doesn’t arise on such aircraft during flight.
“Analysis and laboratory testing of the behaviour of the flight control laws of the A320neo identified a reduced efficiency of the angle of attack protection when the aeroplane is set in certain flight configurations and in combination with specific manoeuvres commanded by the flight crew, as described through Section 2 of Airbus Flight Operations Transmission 999.0059/19," EASA said in a 31 July directive.
“This condition, although never encountered during operations, if not corrected, could lead to excessive pitch attitude, possibly resulting in increased flight crew workload," it said. “To address this potential unsafe condition, Airbus issued the AFM TR, limiting the centre of gravity envelope, which prevents the aforementioned condition, and the Flight Operations Transmission 999.0059/19, providing aeroplane loading recommendations."
To implement this directive, Indian operators of Airbus A320 Neo planes will have to keep the rearmost of its five cargo compartment empty to prevent an excessive rear centre of gravity which could lead to the aircraft to a nose dive under certain conditions. This will bring down the total cargo capacity of such airlines by atleast 1.5 tonnes.
“This is basically a load management issue. Human and cargo weight will need to be appropriately positioned, so that the center of gravity envelope is not disturbed, and there is no issue with the pitch," said a senior DGCA official, who requested anonymity.
Aircraft motion on its lateral axis is called pitch, which is a measure of how far a plane’s nose is tilted up or down.
There are five cargo compartments located in the fuselage of an A320 neo aircraft. While, the load in the first two cargo compartments can be filled, airlines have been advised fewer loads on the third and fourth compartment, while mandatorily keeping the fifth compartment empty, as per the EASA directive.
“DGCA is conducting random checks on the domestic operators of A320 Neo aircraft. In fact we conducted several checks during the last two days as we want to ensure that the directive is implemented properly," the DGCA official mentioned above said.
It must, however, be noted that a scenario involving pitch controllability issues that could lead an Airbus A320 Neo plane to nosedive was identified by French aerospace major Airbus SE on Airbus Development simulator during standard development of new computer system, ELAC System (Elevator Aileron Computer System).
The pitch controllability issue has not occurred on any Airbus A320 neo planes currently flying around the world.
“There is a need to carry out a comprehensive risk assessment in order to ensure that no other possibility exists or all possibility has been reviewed and mitigating actions defines," said Amit Singh, an airline pilot, and a former Chief of Safety at AirAsia.
“There could be a possibility of the front cargo holds (remaining) empty and the rear hold (being) full. Now despite the hold 5 (rear cargo hold) being empty, there could be a combination of passenger, fuel and cargo loading that could exceed the limits in which case system software needs to be amended to control (load) limit," Singh, who is also a Fellow of UK-based Royal Aeronautical Society, said adding that he’s not sure if all Indian operators of Airbus 320Neo have amended the software since such circumstances didn’t arise in the past.
When contacted, officials from Air India and Vistara said they have conducted safety risk assessment before operating empty rear cargo hold on A320 neo planes. Queries sent to IndiGo and GoAir remained unanswered.
"Airlines routinely receive such notices and directives, and the concerned departments act on it. In the case of the Neos directive, we have adjusted our cargo loading accordingly. This was done soon after we received the notice," said a Vistara official, who didn't want to be quoted.
Meanwhile, Airbus is working on reprogramming the software which controls the systems to keep the aircraft flying in a safe flight envelope. The EASA directive is a temporary fix to mitigate the risk, said the DGCA official mentioned above.
“As Airbus studies more scenarios we expect more issues highlighted and remedies. There are active risks and latent risks. If we tinker with a system there is a high possibility that the latent risks come to fore," said Singh. “This for example is a risk that emerged by introducing the bigger engines on the NEO. Therefore it’s imperative to carry out a change management risk analysis."