onsdag 14. oktober 2020

Motor med systemfeil selv etter fix? - Curt Lewis

The PW1100 G-JM Geared Turbo Fan

The Airbus A320neo has two engine options. The GTF engine from Pratt and Whitney (PW) and the LEAP from CFM. The GTF engine is named PW1100 G-JM. The name itself is interesting and is an acronym as below:

  • PW – Pratt & Whitney
  • 1 – Engine model
  • 1 – A320 Family airframe
  • G – geared turbofan
  • J – Japanese Aero Engines Corporation (JAAEC)
  • M – Moteren-und-Turbinen-Union Aero Engines

What is a jet engine

Wikipedia image. Schematic diagram illustrating the operation of a 2-spool, high-bypass turbofan engine, with LP spool in green and HP spool in purple by K. Aainsqatsi.
Wikipedia image. Schematic diagram illustrating the operation of a 2-spool, high-bypass turbofan engine, with LP (low pressure) spool in green and HP (high pressure) spool in purple by K. Aainsqatsi.

Overall, a jet engine functions on the principles of propulsion where air is taken into the engine via a turbine fan in the front. The air is then compressed and passed on to a combustion chamber (the turbine) where it is further compressed and ignited with jet-fuel (a highly refined form of kerosene). This air-fuel mixture expands rapidly and is shot out of the exhaust nozzle at the back of the engine providing forward thrust for the aircraft, and spinning the front compressor blades via a connected shaft, which in turn compresses the inlet air, and the cycle becomes self-sustaining.(Red.)

Pilots Shut Down Pratt & Whitney Engine on Airbus Mid-Air, Even After Fixes


  •  Latest glitch on India’s GoAir not related to previous issues
  •  Engines were compliant with new regulations to fix the problem

Pilots of an Airbus SE A320neo jet in India shut down a Pratt & Whitney engine mid-air last month after it encountered problems, people familiar with the incident said, reviving concerns about the turbines that have been plagued by issues since their debut in early 2016.

The twin-engine jet, operated by Go Airlines India Ltd., landed safely using its other engine in the western city of Ahmadabad on Sept. 19, people familiar with the matter said, asking not to be identified because the matter is confidential. Both the engines’ turbines had already been modified following repeated glitches, the people said. Indian regulators are looking into faults in the engine’s heat-management and oil systems as possible causes, one of the people said.

Representatives for Pratt and GoAir didn’t immediately respond to requests for comment. A spokesperson for Airbus wasn’t immediately able to comment. A representative for the aviation ministry, which oversees the Directorate General of Civil Aviation, didn’t respond to a request for comment.

The latest problem adds another layer to the woes of Pratt, which is owned by Raytheon Technologies Corp. The new engine for narrow-body jets has cost $10 billion to develop but has faced delivery delays and multiple issues leading to mid-air shutdowns. IndiGo, the biggest customer for Airbus’s best-selling A320neo, decided last year to switch away from the engines, placing a $20 billion order instead with rival CFM International Inc., a venture between General Electric Co. and France’s Safran SA.

Outside of durability issues and delivery delays, Indian regulators have been concerned about Pratt’s so-called third-stage low-pressure turbine blades.

India, where the most popular narrow-body market is dominated by the A320neo, mandated in 2019 that all engines must modify that particular component with a different material “less susceptible to impact damage.” Without that tweak, such as was implemented on the GoAir jet, pilots are at risk of one or more engines failing, losing control or worse, crashing the aircraft, according to the DGCA.

It wasn’t immediately clear how many passengers were on board the jet that took off from the southern Indian city of Hyderabad. The plane, registered VT-WGK, didn’t fly again until Oct. 8, data from flight tracking website flightradar24.com show.

India last month ordered GoAir to ground jets that hadn’t had their Pratt engines modified to the specifications mandated by the DGCA.

IndiGo, operated by InterGlobe Aviation Ltd., had already modified all of its engines after regulators granted repeated extensions to meet requirements. Commercial jets can typically fly on one engine even if the other fails.

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