220 Pilots, what are you thoughts so far??

[Gino Under]

Tolerances are tight, but at an identified altitude range and timed power setting. Climb Thrust limit reduces as you near optimum and fuel efficiency improves dramatically at the higher altitudes. AC maintenance obviously feel the risk/reward benefits to climb for efficiency of operation isn’t worth the drama and bad publicity of any engine failure, fire or IFSD. That’s a responsible approach to the AD. But, no reflection on the A220’s capabilities. Right?
The use of manual thrust on the PW1521G, isn’t that finicky to cause such paranoia over the setting of N1 values for climb, but there you go.
Still a great aeroplane.

Gino Under, Ret.

[Fidget]

From an internal document. “Investigations are ongoing to determine the root cause. Preliminary investigation results indicate high altitude climbs at higher thrust settings for engines with certain thrust ratings may be a contributor. This condition, if not corrected, could lead to an uncontained failure of the engine and damage to the aeroplane.“

Nobody is knocking the plane. I personally like it a lot and it will be even better with the new software load. Flt ops made this decision along with commercial decision makers. Obviously management have knowledge that people on this forum don’t have. It’s their plane and we will fly it the way they want. Nobody on this forum will change that. We have the former C Series Chief Pilot and one of their test pilots on staff, I trust what they have to say. Like I said, the moment you go above the N1 limit on the PW1524G-3, a boroscope may be required. It’s that finicky. Like I said no issues for us staying that low since last year. The being said, I don’t wish to stay there forever.

[BMLtech]

Still blows my mind that an engine with this serious of a design issue made it through validation and certification wow.

[fish4life]

Still blows my mind that an engine with this serious of a design issue made it through validation and certification wow.

I think they only found it out after a few in flight shit downs, flight testing can only simulate so much and will never fly anywhere near the number of hours of multiple operators flying multiple planes every day.

[BMLtech]

Still blows my mind that an engine with this serious of a design issue made it through validation and certification wow.

I think they only found it out after a few in flight shit downs, flight testing can only simulate so much and will never fly anywhere near the number of hours of multiple operators flying multiple planes every day.

I have a hard time buying that because this issue showed up so early on in the program. They hang these engines on a 747 flying test bed and take them up to high altitude and wring them out, and with heavy additional instrumentation. How they didn't pick up on this major resonance problem that can cause the engine to shed its guts is beyond me.If anything I would have expected in service problems with the fan reduction gearbox. I think the delay in getting it fixed is a sign that a software update alone may not cut the mustard.While it may be possible for pilots to carefully manage the engine to prevent issues, for certification you will need to be able to ham fist the thrust lever however you want in any part of the envelope without worry.

[L39Guy]

Still blows my mind that an engine with this serious of a design issue made it through validation and certification wow.

It would be difficult to find a new engine, particularly one with a major shift in technology like the geared turbofan engines powering the C-Series, MAX, etc., that did not have teething problems after they are certified and enter operational service.

Both engines types powering the B787 have had difficulties - the CFM's were limited wrt to high altitude/humid conditions for a while, the RR engines had metallurgical issues (I recall but that may not be totally accurate) that had BA, Virgin, etc. grounding their B787 aircraft.

Engines, because they are the key component in the fuel efficiency equation (aerodynamics is pretty mature) are constantly pushing the technological envelope and having difficulties appear once they enter service is par for the course.

[BMLtech]

Still blows my mind that an engine with this serious of a design issue made it through validation and certification wow.

It would be difficult to find a new engine, particularly one with a major shift in technology like the geared turbofan engines powering the C-Series, MAX, etc., that did not have teething problems after they are certified and enter operational service.

Both engines types powering the B787 have had difficulties - the CFM's were limited wrt to high altitude/humid conditions for a while, the RR engines had metallurgical issues (I recall but that may not be totally accurate) that had BA, Virgin, etc. grounding their B787 aircraft.

Engines, because they are the key component in the fuel efficiency equation (aerodynamics is pretty mature) are constantly pushing the technological envelope and having difficulties appear once they enter service is par for the course.

I agree that other new engines have also had serious in service issues. Anything that can lead to uncontained failure is a pretty big deal. Those guys that saved the Quantas A380 deserve a hero cookie for sure. Operating at the edge of technology is risky no doubt. Back in the day most new technology was validated in military service before transitioning to commercial.Now not so much.

[Gino Under]

BMLtech

Nice try.
The current PW1524G issue isn't the same issue that caused the on-ground engine fire and shutdown during initial certification as you've stated without evidence. In fact, the certification flight tests were suspended during the investigation and a remedy found before it was released to continue flight testing.

The CTSB found that;
quote,
1) 0011 section 3.c. (original version) or 2.c. (rev.A), as written, as an alternative equal to the other shutdown options contained in the RSI resulted in the engines being exposed to one or more “hot shutdowns.”
2) The hot shutdowns resulted in heat soaking beyond the design criteria of the No. 4 bearing oil feed tube’s Teflon C-seal.
3) The detrimental effect of heat soaking sustained during hot shutdowns on the bearing compartment tubes’ Teflon C-seals was not foreseen by Pratt & Whitney during the development of Restriction and/or Special Instructions (RSI) No. F-500-001-71-011.
4) Heat soaking caused the oil feed tube’s Teflon C-seal in the No. 4 bearing to fail, which allowed engine oil to merge with the turbine rotor’s cooling air stream.
5) The resulting air/oil mixture then encountered ambient temperatures that were above its auto-ignition point, and the ensuing combustion heated the low-pressure turbine rotor to the point of failure.
6) The failure of the low-pressure turbine rotor was uncontained and resulted in major damage to the engine, nacelle, and wing.

Gino Under

[teacher]

Memo issued. The A220 can be flight planned above FL290 starting Tuesday. Software load will limit N1 to 95.2% and monitor for any exceeded power settings.

Hardware fix more than likely in the new year.

[BMLtech]

How are things now that they let you off the leash? How's it performing at the higher flight levels? Is it climb power limited?

[teacher]

Performing very well. Slight degradation in climb performance at higher altitudes and will probably get worse as loads improve but the fuel burns are amazing and it’s been nice to take advantage of the aircraft’s range finally. Now if only the loads would improve.

[co-joe]

Still blows my mind that an engine with this serious of a design issue made it through validation and certification wow.

I think they only found it out after a few in flight shit downs, flight testing can only simulate so much and will never fly anywhere near the number of hours of multiple operators flying multiple planes every day.

That's a funny typo. It kind of did have a few shit downs didn't it?

[Gino Under]

For anyone who’s interested.

https://www.flightglobal.com/safety/red ... 43.article