gacoon
Pre-takeoff checklist
Whats going on at Auburn University. Half their fleet has been grounded for 6 months or more. And the students are not getting flight time and are way backed up. A real mess as I understand it?
Auburn University aircraft problems
- Thread starter gacoon
- Start date
Maybe the football coaches are also in charge of airplane maintenance?
Larry in TN
En-Route
Is the fuel servo part of the fuel injection system?
All of my 172 time was in older carbureted models.
All of my 172 time was in older carbureted models.
455 Bravo Uniform
Final Approach
- Joined
- Apr 23, 2013
- Messages
- 6,672
- Display Name
Display name:
3G
I can’t find anything mentioning that in a cursory search. Note that Auburn does have a fuels lab that may have been doing something in that space.
Dan Thomas
Touchdown! Greaser!
- Joined
- Jun 16, 2008
- Messages
- 11,430
- Display Name
Display name:
Dan Thomas
The typical injection system as used on the Lycomings. The servo is mounted to the backside side of the throttle body, as you see it at the bottom right, with the "idle valve lever" on it. For the purposes of understanding the fuel regulation and flow, the servo is shown at the top left, with the flow of fuel through it. The regulation system at the bottom left of the throttle body doing the bulk of the fuel flow control. It takes ram air pressure (that varies with airflow velocity) and venturi pressure (that varies inversely with airflow velocity) and uses those against unmetered and metered fuel pressures to get the fuel flow just right for whatever power setting is used. The mixture control allows leaning for altitude or DA, and for idle cutoff.
This system is more complex that that used by Continental. Their system uses a positive-displacement fuel pump that pumps more fuel as RPM increases:
Larry in TN
En-Route
Thanks for all the detail, Dan. I think the newest 172 I've flown was built in the 1980s.
gacoon
Pre-takeoff checklist
Here is a very well written summary of the issues written by the school paper:
www.theplainsman.com
School of Aviation fleet grounding raises questions about engine safety - The Auburn Plainsman
Throughout the fall 2024 semester, Auburn University's School of Aviation has grounded and reintroduced the Cessna 172 fleet of aircraft. Students, employees and admin share their perspectives and concerns.
www.theplainsman.com
Ed Haywood
En-Route
Mentions "contaminated servos" and specifically bad O rings. Bendix RSA servos have millions of hours of reliable service. That suggests somebody is doing something funky.
MauleSkinner
Touchdown! Greaser!
It also sounds like the failed servos were isolated to a particular vendor, and that they were sourcing them elsewhere.
Sounds to me like a reasonable response, yet half of the instructors are concerned about safety. Either there are some serious safety culture issues there, or Chicken Little is running rampant.