Forum: General

Hi,

a few days ago I've had a discussion with someone about the main causes which lead to F-16 mishaps. To me it seems engine failures are one of the main causes in which F-16s are lost, but he told me problems with the fly by wire was the number one cause..

To me that seems quite strange, because I think it's obvious a back-up system can take over when something happens to the flyby wire, while when having for example only one engine, no other engine can take over the loss of power in case the pilot can't fix the engine failure.

I've allready checked the aircraft database on this site, and in many cases an engine failure seems to be the main reason, but I still wanted to ask it in here. For some mishaps the database doesn't display info about what seems to be the reason the F-16 crashed.

Greetings Loube

F-16.net Sponsor

Unlike some other fly-by-wire jets, the Viper does not have the luxury of manual reversion using cables, pulleys, etc. to move the flight controls if the fly-by-wire fails electrically.

In the early Viper days with the PW-200 engine, yes the motor was one of the leading causes of loss. The PW-220 went through a spell of bad turbine blades, as the GE-100 had some fan blade issues as well. Both issues have been engineered out of the design with revised parts and procedures.

With the newer PW-229 (0 USAF losses) and the GE-129 (only 2 or 3 USAF losses) engine caused mishaps are now a rarity.

When comparing the F-16 to other USAF single engine fighters, the Viper is much safer than previous generations of any aircraft/engine combination.

See chart below!
For specific engine rates - http://www.afsc.af.mil/organizations/av ... /index.asp
I'll have to look for the mishap vs engine related cause charts, but I know they're out there! Cheers

Keep 'em flyin' Thumb

TEG

Salute!

Our first loss was pilot error, but the troop punched just short of the runway and lived. The jet pancaked onto the overrun and the two drop tanks, full of gas, burned like crazy. He forgot to close the refueling door, and was in a family model. Gee, why can't I see more gas in the fuse tank? How come I have more drag ( maybe 'cause flaps are down, huh?).

The next few were motor problems.

One guy had a turbine rip thru the fuel tanks and the thing burned like hell as he tried restarts and such. Great video from his wingman, who had a VCR system versus the original film gun camera. Was an OT&E bird - "D" Bell was the pilot.

Next one was a fuel control failure of some sort and the guy couldn't get a good BUC start. We figured out that a) folks were afraid to overtemp the motor using it, b) they didn't practice using it and would actually overtemp the motor. So a few of we folks that had flown the T-33 tried BUC starts in the chocks and found it was exactly like the old motor in the T-33 where the throttle was basically a faucet for the gas going into the motor. In fact, you could get the motor up to idle quicker than the basic fuel control unit! From then on, we added a training task to do a BUC start once a month.

Then we had a deep stall incident at MacDill.

Then we had the infamous FLCS computer shutdown. Stoopid computer geeks didn't want to fry the computers due to over voltage. Instead of switching to the built-in NiCad batteries, the things disconnected from all sources of power. So when the EPU came on uncommanded in the bleed air mode at high rpm, the computer voltage regulators couldn't handle the volts. Poor troop was our first fatality and almost made it despite punchin real low and experiencing 22 negative gees.

Second FLCS loss gave us a big clue, as did an incident at Eglin where the pilot noted the "run" light and reversed throttle before the computers disconnected. As with the fatality incident, the jet went nose down and Wolfman had the 22 negative gees and punched when they got down low enuf to reach the handle.

Another suspicious loss when pilot claimed "all I could see was water and nose was going down". Got out O.K. We were beginning to have some doubts.

that's when we "hot wired" the computers and took our chances with melting the computers. Finally got better voltage regulators and some better bleed air valves for the EPU.

Then we had our first controlled flight into terrain on a night radar run at Eagle Range. Pilot error.

Next loss was another uncommanded EPU, but the computers degraded gracefully and the pilot got out O.K. (later commanded the F-117A Wing).

Then we had the birdstrike that knocked off the radome and mangled all the air data sensors and prolly creamed the electronics in the nose. Got out O.K.

Next ones were the ones that made me feel the worst. One gee-loc and four pilot error crashes.

I will argue with anyone that the basic fly-by-wire was never a problem, and it was better than the current Airbus system as long as you had a 28 volt battery to power the computers. It was the power supplies that caused the FLCS-related crashes. We got the motors running real well within a year or two, so I have no beef with the motor guys.

The pilot error ones were the ones that hurt the most. Three due to doing stoopid things and one due to inattention at low altitude in poor weather.

That's my story, and I'm stickin' to it.

Gums sends ...

P.S. I was there, dammit, and I taught the FLCS for three years in the academic classroom.

Gums wrote:

I will argue with anyone that the basic fly-by-wire was never a problem, and it was better than the current Airbus system as long as you had a 28 volt battery to power the computers.

Unlike the F-16, the Airbus system is set up to keep "lesser" pilots out of trouble and your relatives alive, not to give "superior" pilots the edge.

Nothing's perfect.

OL

The A320 had issues early on with its FBW system, including one very public crash in 1989. But now, the big jets with FBW have multiple power redundancy plus an APU when all else fails. Very unlikely that a jet like today's 320/30/40 will ever be runnin' off just one battery system. We may never know what happened to AF447 unless and until the FDR and CVR are recovered. But it's safe to say it was prolly a once in a billion accident.

I know we have already lightly touched on it so far, but we have lost a lot more aircraft to pilot error, disorientation and not observing established procedures. I am just hazarding a guess here, but I would bet 75-90% of all accidents can be traced back to the pilots or the maintainers. I can't think of a flight control issue in recent memory that caused the loss of a Viper that was either mechanical or design failure.

Ok thx for the info and help guys, seems i've already learned some new things about the Viper and its FLCS Wink

Loube

slaute

sorry for the lowercase, but workshop laptop keyboard just went tango uniform.

the airbus has several 'control laws' for various reasons.

the viper has two - cat one and cat three. they can both be selected. a hybrid 'law' is invoked if the jet loses air data. so the flcs uses 'standby gains' for air pressure, static and dynamic. this keeps you from ripping the wings off, heh heh. they are slightly less than three hundred knots gear up and between one fifty and one eighty gear handle down.

airbus is not a pure gee-command and roll rate command. it also has a different stick arrangement that connects to the electronic doofers than the simple piezoelectric transducers the viper has. so viper drivers can relax [ let go] the stick and the jet does really well in turbulence. no so with the airbus once it kicks off the autopilot and reverts to the 'alternate mode'. then it goes to the 'direct' mode where all the guy does is move the stick as in a 'normal' plane, with a lot less limiting by the basic control laws.

gums sends...

Forum: General

Main cause mishaps?