Post Office Box 23 

Lexington Parlt, Maryland 20653 

5 July 2010 

US Department of Transportation 

Docket Operations 

West Building, Ground Floor, Room W12-140 

1200 New Jersey Avenue, Southeast 

Washington, DC 20590 

Gentlemen: 

I recently reviewed the accident reports for Air Canada 190 and American 587. 

These flights experienced wake turbulence encounters. During these encounters, the vertical stabilizer experienced loads exceeding the design loads. Unfortunately, the stabilizer 

failed on American 587. Because the accident to Air Canada 190 was so similar and 

could have easily been catastrophic, I wish to petition to amend 14 CFR 25.351 (d) to 

read 

§ 25.351 Yaw Maneuver Conditions. 

(d) With the airplane yawed to the static equilibrium sideslip angle of 

paragraph (c) of this section, it is assumed that the cockpit rudder 

control is suddenly returned to neutral reversed to full opposite deflection. 

I have enclosed a copy of a paper which presents the arguments for the proposed 

change. 

This petition is submitted by me as an individual and should not be attributed to 

any organization. If you have any questions, please feel free to write or call me at 301-

257-6887 (Fax: 301-560-5665). 

Thank you. 

Sincerely, 

Richard L. Newman 

enclosure: supporting material 
SUPPORTING MATERIAL FOR RULE REVISION TO §25351(d) 

Richard L Newman, Ph D 

Lexington Park, MD 

Background 

On 12 November 2001, American Flight 587, an Airbus A-300 encountered the wake of a 

Boeing B-747 on departure from New York's Kennedy airport.Q) During this encounter, the 

copilot who was the handling pilot used an excessive amount of rudder during the recovery. 

These rudder inputs led to repeated back-and-forth yawing, coupled with out-of-phase rudder 

applications. These cyclic loads greatly increased the loads on the vertical fin until it failed when 

the loads exceeded ultimate load. 

The investigation revealed that the copilot had been trained to emphasize the rudder use 

during upset recoveries. The National Transportation Safety Board (NTSB) report includes the 

following comment: 

"most American Airlines pilots believed that the airplane would be protected from 

structural damage if alternating full rudder pedal inputs were made at an airspeed 

below maneuvering speed." NTSB ReportQ) 

Many in the industry were surprised to realize that fiill and free use of the flight controls 

at or below maneuvering speed could result in structural failure.(2) 

Response to American-587 

To their credit, the industry and the FAA initiated changes in pilot training to reemphasize the proper use of flight controls during in-flight upsets. This, it was felt, would mitigate the problem of lateral loads on the empennage. 

FAA Sponsored Research 

The FAA also awarded two contracts to the International Air Transport Association 

(LATA) and to Hoh Aeronautics (Hoh). 

lATA Study: The TATA sttrfy(3) surveyed aii4^ pilots worldwide about experiences in 

lateral upsets. Almost 1000 pilots responded. While the final FAA analysis(4) has not been released, it makes two disturbing observations: First, the results indicate that after several years of 

increasing emphasis on proper use of rudder, about a third to a half of the responding pilots indicate they would use rudder during upset recovery. The respondents also indicate they would use 

rudder to correct Dutch roll. 

The results also indicate that a fourth of the pilots believe they have been instructed to use 

rudder during upset recovery and betweem a fifth and a fourth stated that they have been instructed to use rudder during Dutch roll recovery. 

Hoh Study: The Hoh study was a piloted simulation performed in the NASA Vertical 

Motion Simulator to examine the effect of various design alternatives on pilot control of lateraldirectional. This study used a general transport airplane with a variety of rudder designs similar 
Supporting Material for Rule Revision Page 2 

to those in use in current transports. Again, the final report has not been released. However, in a 

presentation to the Aerospace Control and Guidance Committee,(5) Hoh did make the observation that all pilots used the rudder, and many of them also over-controlled. 

Air Canada 190 

On 10 January 2008, Air Canada flight 190 en route from Victoria, BC to Toronto, Ontario, encountered the wake of a Boeing B-747 during climb at flight level 366. Eleven passengers and crew were injured, three seriously. Although the accident to the Airbus A-319 occurred 

in US airspace, the NTSB delegated the investigation to the Transport Safety Board of Canada 

(TSB). The TSB accident report has just been released.(6) 

The sequence of events is remaikably similar to those in the accident to American 587. 

The Ctqitain reacted to the encounter with nine aileron inputs, five to full deflection accompanied 

by sever successive rudder pedal inputs ~ six cyclic rudder reversals with maximum rudder deflections of 6° left and 7° right. The rudder inputs were approximately 90° out-of-phase with the 

lateral excursions. The rear vertical stabilizer attachment fitting experienced a load of 129% of 

design. As in the American 587 accident, the cyclic rudder inputs are believed to have caused the 

peak structural loads. 

The report states that the Air Canada Flight Crew Training Manual discusses the hazards 

of rudder reversals. Rudder reversal is not a topic included in aruiual recurrent training. 

Discussion 

Taken together, these results suggest that the additional rudder and upset recovery training initiatives taken following American 587 have not produced the desired results. This finding 

reinforces the tenet of himian factors that relying on training alone is not likely to be successful. 

Human factors and safety engineering principles generally consider that training is the 

least effective and least desirable approach to risk mitigation. Prevention is to be preferred. In 

the case of rudder reversals causing excessive loads, this means requiring the design to accommodate pilot rudder pedal reversals. 

To prevent future catastrophic rudder failures, I propose amendment of Section 25.351, 

Yaw Maneuver Conditions, to apply full pedal and allow the airplane to yaw to the overswing 

sideslip angle and then achieve a static equilibriimi sideslip. From this static condition, fiill opposite rudder would be applied. 

Specifically, amend Section 25.351 (d) to read 

(d) with the airplane yawed to the static equilibrium sideslip angle of paragraph 

(c) of this section, it is assumed that the cockpit rudder control is suddenly 

returned to neutral reversed to full opposite deflection. 

Some might argue that this proposed change is less stringent than requiring the rudder reversal to occur at the peak of the yaw overshoot. I agree. However, this reversing from the 

steady sideslip is much easier to define than reversing from the overshoot. It will likely prove as 

effective in the long run. 
Supporting Material for Rule Revision Page 3 

References 

1 In-Flight Separation of Vertical Stabilizer. American Airlines Flight 587. Airbus Industrie A300-605R, N14053. 

Belle Harbor. New York. November 12,2001, NTSB AAR-04-04,2004 

2 Discussions at Flight Safety Workshop, Long Beach, California, Society of Experimental Test Pilots, 2002 

3 Survey on Yaw/Roll Upsets: Data Analysis Final Report. International Air Transport Association Contractor Report to Federal Aviation Administration, 2008 

4 LS Peterson, LA Haworth, RC Jones, RL Newman, RJ McGuire, AA Lambregts, T McCloy, and TR Chidester, 

An International Survey of Transport Airplane Pilots' Experiences and Perspectives on Lateral/Directional Control Events and Rudder Issues in Transport Airplanes (Rudder Survey), draft FAA report, 

5 R Hoh, "Criteria to Mitigate Rudder Overcontrol in Transport Aircraft," presented to Aerospace Control and 

Guidance Committee, Stateline, NV, March 2010 

6 Encounter with Wake Turbulence: Air Canada Airbus A319-441. C-GBHZ. Washin^n State. United States. 10 

January 2008. TSB Report A08W007,2010