Alaska Bushwheels
- Thread starter jimpattensc
- Start date
Steve Pierce
BENEFACTOR
Graham, TX
ground loop
Registered User
Anchorage
We have to measure our airplanes before we buy the thrustline mod from Mark. What will Hottshot be requiring from us in the future?
mvivion
SPONSOR
Bozeman,MT
Steve,
That's the bulletin that re-instated the field approval process for big tires, and specifies a mechanism to do so.
In the mid 90's (correct me if I missed the date someone) the FAA came out with a categorical pronouncement to the effect that all these loss of control of Super Cub type airplanes up here in Alaska were the direct result of the use of big tires. In other words, the big tires were causing the airplanes to depart controlled flight.
After a lot of shouting, yelling, etc. by the user community, the FAA actually commissioned a brief flight test program to verify the notion that big tires create havoc with high AOA aerodynamics. What they found was in fact, that the Cub has some pretty attention getting response to aggressive uncoordinated stalls (sorta like most aircraft, duh) but the only negative effects of the biggest tires was a slight reduction in climb rate, cruise speed, etc. None of which exceeded the requirements of the TC, though.
So, essentially, it was a tempest in a teapot. The FAA then developed the referenced guide to field approving big tires, and subsequently Bushwheel started up, and got STC approvals on virtually all their tires on most any airplane you'd want to put them on. I pointed out to this guy that I hardly think that the FAA would issue stc's to Bushwheel for installation of a product that the FAA thought created any negative flight characteristics in your airplane.
The author referenced, though, was out to illustrate that big tires are simply manifestations of machoism, and that in fact they are dangerous, and the FAA was bullied into submission by Senator Stevens on the subject.
By the way, at the same time, Boundary Layer Research had tufted a Cub, and was experimenting with flight characteristics, and he flew his flight test Cub with up to 36 inch tires, finding essentially no detrimental effects, at least as far as controllability goes.
Unfortunately, though, this whole episode distracted everyone from the real causes of loss of control accidents, which are pilot related, and today, we keep killing people in these accidents with alarming frequency. In the meantime, the FAA is really worried about ground loops, since they constituted 50% of the accidents, but are almost never fatal.
MTV
That's the bulletin that re-instated the field approval process for big tires, and specifies a mechanism to do so.
In the mid 90's (correct me if I missed the date someone) the FAA came out with a categorical pronouncement to the effect that all these loss of control of Super Cub type airplanes up here in Alaska were the direct result of the use of big tires. In other words, the big tires were causing the airplanes to depart controlled flight.
After a lot of shouting, yelling, etc. by the user community, the FAA actually commissioned a brief flight test program to verify the notion that big tires create havoc with high AOA aerodynamics. What they found was in fact, that the Cub has some pretty attention getting response to aggressive uncoordinated stalls (sorta like most aircraft, duh) but the only negative effects of the biggest tires was a slight reduction in climb rate, cruise speed, etc. None of which exceeded the requirements of the TC, though.
So, essentially, it was a tempest in a teapot. The FAA then developed the referenced guide to field approving big tires, and subsequently Bushwheel started up, and got STC approvals on virtually all their tires on most any airplane you'd want to put them on. I pointed out to this guy that I hardly think that the FAA would issue stc's to Bushwheel for installation of a product that the FAA thought created any negative flight characteristics in your airplane.
The author referenced, though, was out to illustrate that big tires are simply manifestations of machoism, and that in fact they are dangerous, and the FAA was bullied into submission by Senator Stevens on the subject.
By the way, at the same time, Boundary Layer Research had tufted a Cub, and was experimenting with flight characteristics, and he flew his flight test Cub with up to 36 inch tires, finding essentially no detrimental effects, at least as far as controllability goes.
Unfortunately, though, this whole episode distracted everyone from the real causes of loss of control accidents, which are pilot related, and today, we keep killing people in these accidents with alarming frequency. In the meantime, the FAA is really worried about ground loops, since they constituted 50% of the accidents, but are almost never fatal.
MTV
Steve Pierce
BENEFACTOR
Graham, TX
Sorry I posted the wrong link.
http://www.safetydata.com/tundra.htm
A. FAA flight tests that were completed in April 1995, found
that the effects of a tundra tire installation regarding handling
and stall characteristics on the test aircraft (Piper PA-150), to
be either negligible or within satisfactory limits, and did not
represent a hazard to safety. Additional flight tests on the
aircraft with even larger tundra tires found similar results.
B. The major cause of tundra tire equipped aircraft accidents
appeared to be pilot error. The most common accident scenario was
the pilot allowing the airspeed to drop, in a steep turn, with
his or her attention focused outside of the cockpit. Other
stall/spin accidents with tundra tires were caused by operators
of PA-18 150, who, without FAA approval, removed the 2.5 degrees
of washout at each wing tip.
http://www.safetydata.com/tundra.htm
A. FAA flight tests that were completed in April 1995, found
that the effects of a tundra tire installation regarding handling
and stall characteristics on the test aircraft (Piper PA-150), to
be either negligible or within satisfactory limits, and did not
represent a hazard to safety. Additional flight tests on the
aircraft with even larger tundra tires found similar results.
B. The major cause of tundra tire equipped aircraft accidents
appeared to be pilot error. The most common accident scenario was
the pilot allowing the airspeed to drop, in a steep turn, with
his or her attention focused outside of the cockpit. Other
stall/spin accidents with tundra tires were caused by operators
of PA-18 150, who, without FAA approval, removed the 2.5 degrees
of washout at each wing tip.
FlipFlop
Registered User
Maintaining at Flight Level Zero, requesting lower
Steve Pierce said:
Still the wrong link... HBAW 97-01 was amended by 97-01B to allow field approvals again...
ORDER: 8300.10
APPENDIX: 3
BULLETIN NUMBER: HBAW 97-01B (Amended)
BULLETIN TITLE: Revised Approval Criteria For Tundra Tire
Installations
EFFECTIVE DATE: 04-22-97
REINSTATED DATE: 12-03-02
TRACKING NUMBER: NTSB Recommendation A-95-13
----------------------------------------------------------------
1. PURPOSE. To inform all Flight Standards Field Office managers, supervisors, and aviation safety inspectors (ASI) (airworthiness) that HBAW 97-01 has been revised to incorporate the provisions of the FAA Reauthorization Act of 1996. ASIs will be authorized to issue field approvals for certain types of tundra tire installations.
2. ACTION. ASIs are authorized to perform field approvals, using applicable information in advisory circular (AC) 23-17, Systems and Equipment Guide for Certification of Part 23 Airplanes, as revised, FAA Order 8300.10, volume 2, chapter 1, Perform Field Approval of Major Repairs and Major Alterations, and the following guidance.
A. Each ASI must be trained and authorized before performing tundra tire field approvals. Each authorized ASI must have satisfactorily completed the Aircraft Alterations and Repair course #21811. A signed statement of authorization from the ASI's district office manager will be placed in the ASI's file. The authorization will state that the ASI is authorized to perform field approvals for tundra tire installations. The statement will also include the ASI's background, and training (formal and OJT) with tundra tire field approvals.
B. All tires used for field approved tundra tire installations must be either Technical Standard Order (TSO) or Parts Manufacturer Approval (PMA) approved and limited to size 35x15 tires and smaller.
C. A copy of AC 23-17, as revised, will be given to the owner/operator of the aircraft prior to issuing a field approval for tundra tires.
D. The aircraft will be weighed and a worst case forward and aft C/G for both the aircraft's new empty weight and gross weight must be determined before a field approval is issued.
E. The owner/operator will ensure that the aircraft wing/tail/and control surfaces have not been improperly altered and the aircraft is properly rigged.
F. A series of maintenance operational check flights must be completed with the aircraft and conducted in accordance with the aircraft's flight manual or limitations (ref: Title 14 of the Code of Federal Regulations part 91, section 91.407). One flight(s) will be conducted at minimum weight at the most forward and at the most aft C/G. The second flight(s) must be at gross weight at the most forward and at the most aft C/G. No passengers will be permitted on the maintenance operational check flights.
G. After the flights are completed, the pilot will sign the aircraft's airframe maintenance (log) book, certifying that the aircraft is safe to operate within the operational limits of the aircraft's design.
3. INQUIRIES. This bulletin was developed by AFS-340. Any questions concerning this bulletin should be directed to AFS-340 at (202) 267-3796.
4. LOCATION. The material in this bulletin will be incorporated in FAA Order 8300.10, volume 2, chapter 1, Perform Field Approval of Major Repairs and Major Alterations. Until the new material is incorporated, inspectors should make written reference in the margin of the affected chapter.
/s/ David E. Cann
Manager, Aircraft Maintenance Division
S
StewartB
Cuby,
First, it's a pleasure to see you posting again.
Second, if it' appropriate for you to answer, should we anticipate another policy change in the near future regarding the field approval process? I don't mean a change specific to tires. There's a new rumor in town.
SB
First, it's a pleasure to see you posting again.
Second, if it' appropriate for you to answer, should we anticipate another policy change in the near future regarding the field approval process? I don't mean a change specific to tires. There's a new rumor in town.
SB
aktailwheel
Registered User
Colorado
I finally broke down and bought a pair of 31" bushwheels for the cub, and dang, if they aren't the most fun! I cannot believe what a difference they are off airport. I saw no reduction in speed going from 26" wheels to the BWs, and the landings and takeoffs are shorter. It feels like a completely new airplane. Plus, it looks really cool now.
I don't know why I waited so long to buy them... oh yah, I didn't have the money!
Shane
I don't know why I waited so long to buy them... oh yah, I didn't have the money!
Shane
spinner2
MEMBER
Montana
FA/tires
In considering the purchase of a pair of used 31" Bushwheels made prior to the new radial design but not subject to the AD on older Bushwheels, I asked our Helena FSDO about getting a Field Approval for these tires. They were polite and told me there wouldn't be a problem. The paperwork referenced above was faxed and the final checklist. I was told my IA could sign it off and submit the 337.
It appears as this is the same procedure I went through in 1999 on my Cessna to go to larger tires. I thought that even tire approvals had gotten harder to get in today's wold but that does not seem to be the case.
In considering the purchase of a pair of used 31" Bushwheels made prior to the new radial design but not subject to the AD on older Bushwheels, I asked our Helena FSDO about getting a Field Approval for these tires. They were polite and told me there wouldn't be a problem. The paperwork referenced above was faxed and the final checklist. I was told my IA could sign it off and submit the 337.
It appears as this is the same procedure I went through in 1999 on my Cessna to go to larger tires. I thought that even tire approvals had gotten harder to get in today's wold but that does not seem to be the case.
bush wheels
I like the discussions on these maters. I have been flying over 57 years and hope I'm able to still learn from others experince.
I have had a twisted cub turning around with a load of moose meat with a 3200 tail wheel. the larger tail wheel may have prevented that
I like the discussions on these maters. I have been flying over 57 years and hope I'm able to still learn from others experince.
I have had a twisted cub turning around with a load of moose meat with a 3200 tail wheel. the larger tail wheel may have prevented that
