Looping a 172?

[toolowtoofast]

Heard a great rumour yesterday!

So who was looping the 172 south of NZHN the other day and nearly took out the Waikato Hospital Rescue Helo?????

[PyroTek]

what do you define as looping? out of interest
like a rollercoaster vertical loop?

[Baccalaris]

sounds like its time for good old fashioned wing-clippin' ceremony. :=

[Mere Mortal]

I have heard from a number of different Instructors who all came from the same large school at Moorabbin, that it's OK to barrel roll a C172.

Can't remember reading that in flight manual.

Remember kiddies, it's always fun til the cops show up.

MM

[WannaBeBiggles]

A proper executed barrel roll should only be a +1G maneuver (correct me if I'm wrong)

[scrambler]

A roll is an aerobatic manoeuvre. A 172 is not certified for aerobatic flight. Correct me if I am wrong.
I have heard from a number of different Instructors who all came from the same large school at Moorabbin, that it's OK to barrel roll a C172.
Would this be the same school where instructor classes talk of looping warriors?

[VH-FTS]

Oh no, here comes the 'barrell roll is a 1g maneovure' discussion. A barrell roll is not a 1g bit of flight, it is effectively a combination of a roll and loop and 3g is common.

An aileron roll can be a minimal 'g' maneovure, which is what they mean. Sounds like these Moorabin instructors are showing off to the youngens and I bet have never been upside down in their life.

Back to topic, I'd hate to be the owner of the mentioned C172 down the track when fatigue starts creeping into the airframe.

[GetOffMyBack]

I was a passenger in a Navaho a few years ago training for parachute ops in Tully FNQ. This joker of a pilot whilst on decent thought it would be cool to perform a few rolls, I shat myself and can tell you they were definitely not coordinated. The guy didn't have any training of such maneuvers except for some hard earnt time on Microsoft flightsim.

[VH-XXX]

Here we go again...

http://users.netconnect.com.au/~njah1/MichealJacksonPopcorn.gif

I've heard this so many times before. It's been done many times before and will be done many times more.

You'll probably find in the end it was an 152 Aerobat or something.

ANY and EVERY aircraft (excluding obvious exclusions) will loop, barrel roll, aileron roll, stall turn etc, etc and such manevures are probably within most of these aircraft's g limits, however as there is usually little margin in the certification limits, it is not advisable.

I know people who have looped 172's, Jabiru and an Aerostar and are still alive to tell the tale and will probably never come unstuck, but one day, someone might fall out the bottom of a barrell roll and end their life because the aircraft wasn't designed for it. Not a good result.

(Sorry to steal Michael, however it's a great gif)

[Capt Fathom]

Don't Try This At Home! (http://www.metacafe.com/watch/84664/airplane_crash/)

The plane is a Partenavia P68C.

The crash was during an airshow in Plainview, TX.

The pilot was a sales rep giving a aerial demonstration that included high-G maneuvers in a plane not designed for them.

The NTSB summary is:

Accident occurred Sunday, September 11, 1983 in PLAINVIEW, TX

Aircraft:PARTENAVIA P68C, registration: N29561 Injuries: 1 Fatal.

THE PILOT WAS EXECUTING A HIGH SPEED PASS OVER THE RWY AT ABOUT 250 FT AGL.

THE PILOT THEN BEGAN A RAPID PULL-UP & BOTH WINGS SEPARATED JUST OUTBOARD OF THE ENG NACELLES.

RECONSTRUCTION OF THE SEQUENCE FROM A VIDEOTAPE REVEALED THAT THE AIRCRAFT'S SPEED AT THE TIME OF THE WING SEPARATIONS WAS 220 KTS.

VNE FOR THE AIRCRAFT IS 193 KTS.

IT WAS CALCULATED THAT, AT 220 KTS & AN 8 DEG NOSE-UP PITCH, THE 'G' LOAD AT THE TIME OF THE WING SEPARATIONS WOULD HAVE BEEN 8.3 G'S.

The National Transportation Safety Board determines the probable cause(s) of this accident as follows:

IN-FLIGHT PLANNING/DECISION IMPROPER: PILOT IN COMMAND
OVERCONFIDENCE IN AIRCRAFT'S ABILITY. PILOT IN COMMAND
AIRSPEED..EXCEEDED: PILOT IN COMMAND
WING OVERLOAD. DESIGN STRESS LIMITS OF AIRCRAFT EXCEEDED: PILOT IN COMMAND

Contributing Factors WING FAILURE, TOTAL WING SEPARATION.

The really tragic thing about the video is the woman screaming in the background over the PA. It is the pilot's wife, who also served as narrator during the routine.

[Aerodynamisist]

Single engine non aerobatic aircraft like the 172 are normally certified to +4.4 -2.2g, if your technique is not perfect you will easily exceed this in a loop. If on the other hand your technique is perfect and you get the loop done at 4g all you have to do is hit a bit of turbulence say a 3 g bump (if your technique is really good your own wake can give you a 2 g bump) and then your instantaneously at 6 or 7g. My guess is the 172 would fail out board of the strut attach points between the flaps and ailerons or it would break its back rearward of the luggage door. Maybe not the first time or maybe not the first 100 times but it will happen.

[toolowtoofast]

AFAIK there's no aerobats around NZHN - I'll stand corrected on that though. There is one over at NZTG, but they would have been a long way from home on a x-country throwing a few aeros in to liven it up, and I can't see that happening....

There's a ****e load of 172's though....

And as for aeros in a 172/PA28, that conversation was last month.

[404 Titan]

Aerobatic Figures
by Dr. Guenther Eichhorn
Barrel Rolls

The Barrel roll is a combination between a loop and a roll. You complete one loop while completing one roll at the same time. The flight path during a barrel roll has the shape of a horizontal cork screw. Imagine a big barrel, with the airplanes wheels rolling along the inside of the barrel in a cork screw path. During a barrel roll, the pilot always experiences positive Gs. The maximum during the maneuver is about 2.5 to 3 G. The minimum about 0.5 G.

Can I do acrobatics in a non-Aerobat C-152?

Sure, you *can*. HOWEVER: If the maneuvers are not listed as approved in the Pilot's Operating Handbook, you have done something illegal (and quite stupid to boot, since it would be quite dangerous).

The changes made to the C-150 & C-152 are not very visible, but are extensive. Cessna was worried about people doing aerobatics in the non-aerobatic version, so the original paint jobs given the aerobatic versions were quite distinctive.

What might confuse things a bit for the uninformed is the appearance of a "normal" airplane doing aerobatics at a local airshow. An experienced acro pilot should be able to put on a decent aerobatic show in many of the "standard" category aircraft. There are a couple of problems with this, though. THERE IS NO ROOM FOR ERROR! Aerobatic category ships have a strength reserve for the maneuvers for which they are approved. For example, even a low power/weight craft should be able to do a nice loop and not exceed +3 G's. A normal category plane is certificated to +3.8, aerobatic to +6. A Bob Hoover can do it safely, you can't. The other problem is, if you do maneuvers outside what's listed in the POH, you now have an experimental airplane. Hoover's Shrike and other "normal" category airplanes on the airshow circuit, have been re-certificated under Experimental-Airshow/Exhibition.
How an Aircraft is Certified.
Limiting loads and ultimate loads

To receive “type approval certification” the design of a general aviation aircraft must conform with certain standards, among which are the in-flight “manoeuvring loads” plus the “turbulence induced loads” which the structure must be able to sustain. The turbulence loads are called the gust induced loads. FAR part 23 is the recognised world standard for light aircraft certification and the following is an extract: "... limit loads are the maximum loads to be expected in service i.e. the highest load expected in normal operations and ultimate loads are limit loads multiplied by a safety factor of 1.5. The structure must be able to support limit loads without detrimental, permanent deformation. At any load up to limit loads, the deformation may not interfere with safe operation. The structure must be able to support ultimate loads without failure for at least three seconds ..."

The minimum positive limit load factor which an aircraft in the 'normal' operational category (at maximum take-off weight) must be designed to withstand is 3.8g. For a non-aerobatic aircraft the negative limit load factor is 0.4 times the positive limit which makes it 1.5g for the normal category. The ultimate loads for the normal category are +5.7g and -2.25g.

For aircraft with aerobatic capability the negative limit load factor must be 0.5 times the positive value. The 'utility' category (which includes training aircraft with spin certification) limit loads are +4.4g and -2.2g while the 'acrobatic' category limit loads are +6.0g and -3.0g.

The manufacturer of a particular aircraft type may opt to have the aircraft certificated within more than one category in which case there will be different maximum take-off weights and centre of gravity limitations for each operational category.

It should be borne in mind that the sustainable load factors only relate to a new factory built aircraft. The repairs, ageing and poor maintenance, to which it has been exposed since leaving the factory, may decrease the strength of individual structural members considerably.

The point I’m trying to make here is:

DON’T DO AEROBATICS IN NON AEROBATIC AIRCRAFT.

[WannaBeBiggles]

And I stand corrected on the 1G maneuver call :\

Unfortunately as long as we have aeroplanes and pilots we'll find cowboys who think they are invincible. When I mention that I am training to be a pilot I have had a few people respond that they also have a friend, (aquaintence, family member etc) training to be a pilot and that they have taken them up and showed them a few "aerobastics", which from the way they explained the maneuver were wing overs and a quick 2-3G pull up and dive to give the illusion of zero G.

Now even if these aren't aerobatic maneuvers it's disturbing to know that some think they have the right to take another persons life in to their own hands when they are not trained for this sort of stuff. They would be absolutely :mad: if the wing over wasn't executed properly stalling a wing and developing a fully developed incipient spin!

[VH-Cheer Up]

They would be absolutely if the wing over wasn't executed properly stalling a wing and developing a fully developed incipient spin!

If it's fully developed, it isn't an incipient spin any more. It's a fully developed spin (usually two rotations).

Everyone should have spin training in an appropriately-certified aircraft so they know how to get out of one. I think accidental spins used to get more GA pilots than any other thing they could get wrong. Not sure if that's still the case. Spin training was part of my basic training 35 years ago and I would hope it's still part of basic training these days.

[WannaBeBiggles]

I stand corrected.... again... :ouch::}

[hard_yakka]

All I can say is I hope that the aircraft was privately owned. I rent 172s from time to time in Hamilton and I would hate to think that I was getting into an aircraft that some plonker had decided to risk overstressing just to impress someone.

The fact that there was no "smokin' hole" video on the TV news proves that the pilot "got away with it" that time. The next poor bugger who innocently encounters a bit of turbulence in a weakened airframe and has an inflight structural failure may not be so lucky.

If the aircraft is a rental (and was actually aerobat-ed), I hope the pilot is reading this and has the guts to own up and have the aircraft inspected to ensure that someone else doesn't cop the results of their poorly judged antics.

Did the Air Ambulance chopper file an incident? I haven't heard any buzz or scuttlebutt...

[2dotsright]

I can't believe that there aren't more people who are appalled by this sort of cowboy nonsense. As someone said though, pity the poor fella who is in that aircraft when the stress catches up with it later and its airframe fails. It's not smart to do this sort of thing and anyone caught should lose their licence for a very long time. I was teahing a young bloke to fly many years ago, and woke to the news one morning about a light aircraft crash, killing both occupants. Turned out that my student was the hapless passenger in a non aerobatic aircraft with a non aerobatic pilot who decided to show off at a low level and killed them both. Don't encourage this sort of behaviour and dob the idiots in if you hear of it. You may save some lives someday.

[Peter Fanelli]

404 Titan
Most 172's are not certified to FAR 23 standards. Only the 172 Q R S and RG fall into that category. The others and indeed most light aircraft are certified under CAR 3 rules.

[toolowtoofast]

I'm about 2000nm away at the moment, so don't know any more than what I heard. It could just be a rumour for all I know.

[404 Titan]

Peter Fanelli

I will grant you that the earlier models of C172 (up to the “P” model) were certified under CAR Part 3 but all light aircraft designed and produced after the 1st February 1965 are certified under FAR Part 23. The grandfathering of aircraft originally designed prior to this date was allowed.

Later aircraft such as the C177 and Cirrus SR20 are certified under FAR Part 23. To say most current light aircraft were designed under CAR Part 3 is a slight stretch. Let’s just say a very large proportion of them were.

Have you got a copy of the design standards under CAR Part 3? I have tried searching without any luck. It would be interesting to see what the differences are regarding “Limiting Loads” and “Ultimate Loads”. I don’t think there will be much though?

[VH-XXX]

Fair go, the BAK is pretty comprehensive these days!

[djpil]

Have you got a copy of the design standards under CAR Part 3? I have tried searching without any luck. It would be interesting to see what the differences are regarding “Limiting Loads” and “Ultimate Loads”. I don’t think there will be much though?
CAR 3 is still available at http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgccab.nsf/MainFrame?OpenFrameSet
Quite a bit of difference in the flight loadings.
Worth repeating:
I can't believe that there aren't more people who are appalled by this sort of cowboy nonsense .... Don't encourage this sort of behaviour and dob the idiots in if you hear of it. .... but the idiots never listen.
Would this be the same school where instructor classes talk of looping warriors? .. one instructor was dobbed in by some-one who witnessed it and I've heard that's not the only flying school he's been kicked out of.

[404 Titan]

djpil

Thanks for that.:ok:

CIVIL AIR REGULATIONS

PART 3—AIRPLANE AIRWORTHINESS—NORMAL, UTILITY, ACROBATIC, AND
RESTRICTED PURPOSE CATEGORIES

SUBPART C—STRENGTH REQUIREMENTS
GENERAL

§ 3.186 Maneuvering load factors.

(a) The positive limit maneuvering load factors shall not be less than the following values (see Fig. 3-2):

N = 2.1 + (24000÷(W + 10000)) ---------Category N

except that n need not be greater than 3.8 and shall not be less than 2.5. For airplanes certificated as characteristically incapable of spinning, n need not exceed 3.5.

n = 4.4--------------------------------Category U
n = 6.0--------------------------------Category A

(b) The negative limit maneuvering load factors shall not be less than -0.4 times the positive load factor for the N and U categories, and shall not be less than -0.5 times the positive load factor for the A category.

(c) Lower values of maneuvering load factor may be employed only if it be proven that the airplane embodies features of design which make it impossible to exceed such values in flight. (See also § 3.106.)


So what I have gathered from this is that aircraft manoeuvring load limits under CAR Part 3 are:

Normal category:

+3.8g but not less than +2.5g. If A/C is incapable of spinning then it doesn’t need to be greater than +3.5g.
&
-1.52g

Utility category:

+4.4g
&
-1.76g

Aerobatic category:

+6.0g
&
-3.0g

FAR PART 23—AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES

23.337 Limit maneuvering load factors.

(a) The positive limit maneuvering load factor n may not be less than—

(1) 2.1+(24,000÷(W+10,000)) for normal and commuter category airplanes, where W=design maximum takeoff weight, except that n need not be more than 3.8;

(2) 4.4 for utility category airplanes; or

(3) 6.0 for acrobatic category airplanes.

(b) The negative limit maneuvering load factor may not be less than—

(1) 0.4 times the positive load factor for the normal utility and commuter categories; or

(2) 0.5 times the positive load factor for the acrobatic category.

(c) Maneuvering load factors lower than those specified in this section may be used if the airplane has design features that make it impossible to exceed these values in flight.

So what I have gathered from this is that aircraft manoeuvring load limits under FAR Part 23 are:

Commuter category:

+3.8g
&
-1.52g

Normal category:

+3.8g
&
-1.52g

Utility category:

+4.4g
&
-1.76g

Aerobatic category:

+6.0g
&
-3.0g

So in conclusion apart from having a new category in Commuter class, I really can’t see any difference in the manoeuvre load limits between CAR Part 3 and FAR Part 23.