January 14, 2013 at 1:34 am #84022
I was departing KFTW today for a quick flight over to KDTN to pick up some passengers. Take off went normal with engines developing full power, RPMs matching, and fuel flows both where they needed to be. I don’t usually reduce TO power settings until 500-800 AGL which usually gives me time to accelerate to 140 mph while gaining some altitude at the same time. As soon as the gear locked up in the wells (and at 2-300agl) I heard the familiar sound of the gear motor stopping and doors closing on our 421B, all of a sudden airplane started yawing to the left, MP dropped to around 25″, and left engine began surging coughing and not responding to throttle inputs. A quick scan showed good CHT and EGTs with my FF being drastically reduced so I immediately thought of a fuel pump failure and the low setting on the AUX pumps not being able to keep up.
Aux pump went to high with the engine giving one final surge (no matter the mixture, throttle, or prop setting) and she was pretty much done. Got the engine caged, climbed up, and returned to FTW without much of a problem. Was able to get a hold of Bruce at Brodie Aviation who came out on a Sunday to at least take a look to see what happened as when I got on the ground, the engine would start, but not stay running, and there was no oil leak anywhere.
We found the Engine Induction Tube coming off of the turbo had popped off of the turbo housing thus disrupting the air/fuel mixture and causing me to have the problems. The clamps did not fail, although it was loose enough not to keep the hose where it needed to be. Right side was tight and no problems. Got it fixed and I was on my way.
My question is has anyone else had this type of problem? It was great to validate the training that I do and thankfully I was without passengers, but to think of something as simple as that one clamp….wow!January 14, 2013 at 3:31 am #97707
Wow, that is really a great report, the type I do like reading as it worked out well.
There ares so many variables to safe flying, I have looked at those induction tubes so many times but never really close; not anymore.
Glad this all worked out for you.
JimJanuary 14, 2013 at 6:02 am #97708
Wow … Amazing to see training at work safely … Thanks for sharing and ill be looking a bit closer from now on …January 14, 2013 at 1:27 pm #97710
Glad you’re here to write about it! Seems your training worked very well.
I have heard about induction leaks and hoses popping off causing these issues. Happened to a Malibu at FL250 a friend of mine was in about 20 years back.January 14, 2013 at 1:36 pm #97711
Good job! What was your actual climb rate after you got the engine caged? How light were you?
Again, I’m glad it turned out so well.January 14, 2013 at 1:44 pm #97713
Nicely handled. I have not had a problem with the tube popping off, but I have looked at several of those and found holes. Some shops don’t remove them at annual, but I think it is a good idea they seem to crack and get holes where they can be seen until flexed. Not your the cause of your problem in this case, but something to keep an eye out for.January 14, 2013 at 4:43 pm #97716
Anytime maint is done to the induction tubes it is worth checking them with a 2nd set of hands. Also worth while to check again after next oil change, etc as the hose will compress a bit.
The induction system is not really tested until you get up high as that is when the differential pressure is the highest.
Good job on the recovery!January 14, 2013 at 6:03 pm #97718
Nice job! That’s the way it’s supposed to work and why we have 2 engines.
RobertJanuary 14, 2013 at 6:19 pm #97720
Excellent job! and thank you for sharing this!
I too would be interested to know what kind of climb rate you had, weight and OAT.January 15, 2013 at 6:57 am #97732rwelshParticipant
most times if the manifold pressure drops below ambient, there is some kind of induction leak, turbo pressure leak or turbo failure. The place I have found bad ducting is the elbows between the intercooler and the intake tube assembly. These ducts have special high strength clamps although I have seem regular screw clamps on some which is a no-no.January 15, 2013 at 9:42 pm #97744
I had 196 gallons on board and was solo (thankfully). It was also cool outside….around 40 I think. I was seeing a pretty good climb rate due to me not having to gain speed, but was around 400-500fpm initially, although to be honest with you, after I saw positive rate, I was busy keeping an eye on airspeed 😀
The airplane climbed without a problem once I got the engine feathered, but when it was trying to run (or quit depending on how you look at it), the drag was very significant and the nose had to come way down from normal climb attitude to keep the speed up. I would almost equate it to having to shove the nose down in a single after rotation to maintain your speed, although not quite that dramatic.
The clamps on the hoses were the correct ones too. I am not sure what happened, but they will definately be on my “to check” list during each oil change just like the exhaust!
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