The additional virtue is it probably costs 15X compared to kerosene. And you won't be able to transport in a pipeline.

(Written on 20.03.2021)(Permalink)

Looks like the hollow fan blade in these 112 inch fans needs a life limit. Fan blades are critical parts that are supposed to meet fail-safe design criteria. Read about the 2018 failure on N773UA and the OEM inspections performed on these blades. UAL is probably relieved that these blades were inspected by PWC.

(Written on 27.02.2021)(Permalink)

Thanks for correction. Expect an AD to add the disagree indjcator.

(Written on 22.03.2019)(Permalink)

I read where there is an option to have dual AOA sensors, which are on most of the US fleet and would identify a failed sensor. Both accident aircraft only had one AOA sensor. Pilot training is an obvious issue as well as it is reported the Lion Air jet had an identical incident the day before where a jumpseat pilot instructed the crew how to disconnect so some pilots do know how to respond. Also read that engineers within FAA certification were concerned that the aerodynamics of the MAX-8 were sufficiently different to warrant a new type certificate instead of adding it to the existing TC. The ODA process is also going to come under scrutiny here.

(Written on 22.03.2019)(Permalink)

Crew did a great job, probably a good thing the captain had fighter experience to know how to breathe during the explosive decompression event. Very sad a passenger lost her life--prayers for her and her family. Pretty early to blame "missed or improper inspection". We blamed UA 232 on improper inspection based on finding residue of fluorescent penetrant vaporized from the crack surface of the disc remnant. This became the foundation of "human factors" in nondestructive examination (NDE), i.e., although we have vast amounts of technical data instructing the human to carefully inspect the center bore area of the disc, we still missed the crack 800 hours earlier during maintenance--which to this day I believe is BS but full disclosure--my father worked for UAL for about 43 years. Later we learned the same chemical is also found in turbine engine oil--wow, that's really strange that turbine engine oil might be found on a turbine engine part in an area near a rotating air/oil se

(Written on 18.04.2018)(Permalink)

That ain't "just a cowling". Looks like the fan and compressor too. Pretty serious failure.

(Written on 17.02.2018)(Permalink)

Thought I heard a report that the front tire blew and pieces were ingested in an engine. A dragging bearing could cause the tire to overheat and fail during the takeoff roll. If that happened at rotation, it could explain the abort and hard smash to the nose gear and although the airplane is certified to be able to take off on one engine at that point, why chance a go around if you can park it? FDR should be helpful in sorting events here.

(Written on 15.03.2014)(Permalink)

How do you say "Oh s*it" in Koregian?

(Written on 09.07.2013)(Permalink)

This looks like a late stage compressor blade failure. Uncontained blade release, no damage to A/C, engine shutdown and air return with safe landing. Crew had a few exciting moments but overall no big deal except the cost of repair. Old A/C does not equate to old engine--I think I saw this bird land in PHX in 1989, it was cool as you can get pretty close at Sky Harbor. At the time of UA232 the thinking was that rotating parts were designed with a safe life and no inspection would be required. This has changed since to inspect at each opportunity.

(Written on 03.11.2011)(Permalink)

You're not going to be able to contain fracture/failure of a rotating component like UA 232 (Sioux City) even with a Kevlar nacelle. This was the result of metallurgical defects in the fan disk, they blamed UA maintenance but the cause was the defect in the fan disk. Turbine blade failures are by regulation required to be contained by engine design or shown to pose no threat to the A/C in flight. Fan blades are critical engine parts though.

(Written on 03.11.2011)(Permalink)