View Full Version : F16 engine error
AmericanFlyer
27th Oct 2017, 04:52
Air Force loses $22M F-16 due to engine assembly error - CNNPolitics (http://edition.cnn.com/2017/10/26/politics/f-16-crash-engine-investigation/index.html)
Capn Bloggs
27th Oct 2017, 05:05
Afterburner on steroids...
dr dre
27th Oct 2017, 06:11
Tragic Error
The pilot was able to safely eject and did not sustain any injuries but the aircraft was destroyed as it hit the ground.
Why use the term "tragic" if no people were killed or injured?
Smilin_Ed
27th Oct 2017, 09:46
An investigation into the mishap revealed evidence that "the main engine control was missing a required 600-degree training ring and the anti-rotation pin," according to the Air Force.
Back to the subject at hand: Could this have been a "retaining ring"?
I love the comment in the article reference in the OP:
Large portions of the aircraft, including a wing and the fuselage, were found intact after the crash, allowing investigators to identify it as an F-16,
Wow! Lucky to have such experts available!
:E
[and yes, I do appreciate that it's just a stupid comment by a less-than-expert journo, but it made me laugh!]
F-16GUY
27th Oct 2017, 10:26
Afterburner on steroids...
It wasn't even in afterburner when the engine ran away. Just goes to show how much higher temperature translates to more power. We had an engine, although a PW one, go 50 degrees past max FTIT for a few seconds, and the pilot described it as getting a kick in the back. The one in this incident went something like 200 degrees plus past its maximum, resulting in plenty of thrust for a short time, and then a melted turbine section as the pictures in the accident report clearly show.
The F-16 is equipped with a max power switch that is in place for war/emergency use only. Engaging it will allow the FTIT to increase by 20 degrees for a short duration of time giving more thrust for a bugout or what have you. It also reduces the engine overhaul time from 600 hours to just 6 hours...
The use of new and more heat resistible materials in engines translates into more power or more hours between engine overhauls. The PW -232 could achieve in excess of 32.000 lbs of thrust compared to the PW -220's 25.000 lbs without any major aircraft modifications (F-16), and it could reach 37.000 lbs with a redesigned intake. That would almost get you a 1 to 1 thrust/weight in a fully combat loaded jet. Just imagine....
number0009
27th Oct 2017, 10:57
Could this have been a "retaining ring"?
Yes, you have that right. Apparently the MEC was replaced a couple of days prior to accident.
AIB Report:
http://www.airforcemag.com/AircraftAccidentReports/Documents/2017/040517_F16_Andrews.pdf
Records indicated the mishap engine (ME),
serial number (S/N) 509307, went through a modernized digital engine control (MDEC) upgrade
to comply with TCTO 2J-F110-838 on 31 March 2017, and had accumulated 0.0 flight hours prior
to the mishap (Tabs D-25 and U-3 to U-4).
Engine Shop received the overhauled MA MEC from
the supply system on 3 April 2017, and MA MEC was installed on ME S/N 509307 and passed an
operational engine run test on 4 April 2017 (Tabs D-13, D-23, and J-4).
600-degree spiral retaining ring
melmothtw
27th Oct 2017, 13:49
I love the comment in the article reference in the OP:
Quote:
Large portions of the aircraft, including a wing and the fuselage, were found intact after the crash, allowing investigators to identify it as an F-16,
Wow! Lucky to have such experts available!
[and yes, I do appreciate that it's just a stupid comment by a less-than-expert journo, but it made me laugh!]
From the article (bold mine): Large portions of the aircraft, including a wing and the fuselage, were found intact after the crash, allowing investigators to identify it as an F-16, police said at the time of the incident.
Perhaps your guffawing should be directed at the Maryland Police, rather than the journo.
scifi
27th Oct 2017, 16:57
Quote.... That would almost get you a 1 to 1 thrust/weight in a fully combat loaded jet. Just imagine....
WOW, I am just imagining.... That would make it able to hover like a Helicopter...!!
.
.Or like a Harrier...
lomapaseo
27th Oct 2017, 19:23
Agree that more fuel than wanted means more temperature in the turbine and rapid wear-out. However, it also means more RPM and if it meters passed that emergency response line it may drive the rpms into very bad vibratory modes and fatigue of the disks in very short order.
Such possibilities will require full strip and replacement if confirmed via recorders. In this case with the plane crashed I doubt anybody is looking to reuse anything :0
F-16GUY
27th Oct 2017, 20:00
WOW, I am just imagining.... That would make it able to hover like a Helicopter...!!
.
.Or like a Harrier...
Why imagine something ugly if you can imagine something cool? BTW, I didn't know the Harrier could hover with a full combat load...
F-16GUY
27th Oct 2017, 20:10
Agree that more fuel than wanted means more temperature in the turbine and rapid wear-out. However, it also means more RPM and if it meters passed that emergency response line it may drive the rpms into very bad vibratory modes and fatigue of the disks in very short order.
Such possibilities will require full strip and replacement if confirmed via recorders. In this case with the plane crashed I doubt anybody is looking to reuse anything :0
On the PW engine the DEEC will normally try to maintain the RPM within limits despite the higher temperature, by closing the nozzle. The GE probably does the same, but the amount of fuel was probably so great that the RPM still went above 110%. The pictures show that all the blades on one of the turbine wheels have lost the outer one third. They look as if they have melted away.
NutLoose
27th Oct 2017, 20:18
Didn't the early Tornado used to runaway if you lost the computers?
F-16GUY
27th Oct 2017, 20:30
Didn't the early Tornado used to runaway if you lost the computers?
Yep, never trust electrical components made by LUCAS!!! Reminds me of my dads old Matchless bike....
Vendee
27th Oct 2017, 21:03
Didn't the early Tornado used to runaway if you lost the computers?
Still does AFAIK. Not only did the engine lose its top speed governor, it lost its controlled rate of acceleration so it went to overspeed very, very quickly..... and then went quiet. I can't remember the details but they lost a GR1 quite early on when the pilot was groping for the wander lamp at night and operated the crash bar by mistake. Both gennys and the battery gone, followed quickly by both engines and a Martin Baker tie for the crew.
OK465
27th Oct 2017, 21:19
Oh, the good old days of fuel metered directly by pilot throttle movement in those old centrifugal flow engines. :}
Stu666
27th Oct 2017, 21:57
I love the comment in the article reference in the OP:
Wow! Lucky to have such experts available!
:E
[and yes, I do appreciate that it's just a stupid comment by a less-than-expert journo, but it made me laugh!]
And there was me thinking it was an SR-71 :E
tdracer
28th Oct 2017, 01:26
Oh, the good old days of fuel metered directly by pilot throttle movement in those old centrifugal flow engines. :}
Wouldn't make much difference if the fuel control was assembled incorrectly...
Don't they do an engine check run after replacing fuel control components? I'd think that would be mandatory, especially on a single engine aircraft.
Fonsini
28th Oct 2017, 02:02
It must be a strange experience to pull back on the throttle and experience an increase in thrust. Whoa horsey.
OK465
28th Oct 2017, 14:05
Wouldn't make much difference if the fuel control was assembled incorrectly...
Oh, the good old days of fuel control mx done by mechanics....not IT guys.
VinRouge
28th Oct 2017, 18:35
. The pictures show that all the blades on one of the turbine wheels have lost the outer one third. They look as if they have melted away.
Roughly 2/3 of the stresses on a turbine blade are centripetal. The remaining third is thermal and bending, focussed on where the blade meets the root. It doesn't take much of an overspeed to cause significant creep (especially at close to maximal operating temps). Blade life is usually a function of creep burst (the blade stretches as it's life goes on).
And yes, any overspeed is likely to take the entire assembly into resonant modes that may result in untold High Cycle Fatigue and ultimately failure. It is likely the remainder of the blades was scraped off in the casing of the hot section as they stretched like toffee.
Salute!
Maybe help from new Viper drivers, but I do not unnerstan why there was no FCF after engine maintenance as described.
The Viper had less FCF requirements than anything I flew back then. We could even replace the FLCS boxes before flying and if the "extended" BIT was good, we flew. But the motor? And it has more mechanical stuff than the FLCS actuators and hydraulics.
One good example of less FCF's was my leading edge flap failure, and in my 4,000 hours I only had one emergency due to the wrenchbenders. Needless to say, after getting that thing back on the ground I had "perfect" jets for the rest of my time at Hill.
My profile here has a pic of the LEF, and it folded up because the two dudes working on the drive motor did not place a "keeper" pin in the drive tube and the shaft slipped out just after lift-off. The sensors indicated all was well during the various checks.
So I question the lack of a check on that motor as it was one of biggies we had back then in both the Sluf and Viper.
Gums sends...
NutLoose
29th Oct 2017, 01:30
It must be a strange experience to pull back on the throttle and experience an increase in thrust. Whoa horsey.
French, Italian and Japanese used reverse throttles during the war, indeed the American built Trojan used by the French followed the same format into the sixties.
https://aviation.stackexchange.com/questions/39441/has-there-ever-been-a-plane-with-reversed-flight-controls/39443
West Coast
29th Oct 2017, 03:00
Is there an advantage to reversing the throttles other than the possibility of commonality with other aircraft in the force?
SpazSinbad
29th Oct 2017, 07:39
Is there an advantage to reversing the throttles other than the possibility of commonality with other aircraft in the force?
[I'm jokin' - rite?] :} Would be useful in NavAv aircraft for the catapult stroke - the lateral G force would keep the throttle BACK & Wide Open - cool. :}
NutLoose
29th Oct 2017, 09:50
I wonder if it was to do with the stick?, you would pull back to climb, push forward to descend, logic says the throttle would operate in a similar manner,