January 17, 2012

To Whom It May Concern

U.S. Department of Transportation

Docket Operations

West Building Ground Floor, Room W12‐140

1200 New Jersey Avenue, SE.

Washington, DC 20590

Subject:   Petition for Revision to Exemption 5146A to Expand Aircraft Model Applicability

Reference:   FAA Exemption No. 5146A

Background:  

Per 14 CFR 11.61(b) Raisbeck Engineering (REI) petitioned for an exemption from a portion of 3.242 (b)

of the Civil Air Regulations (CAR).  This allowed REI to certify its gross weight increase Supplemental Type

Certificate (STC) on Beechcraft (HBC) Model 90 aircraft without requiring installation of fuel jettisoning

systems.  This was accomplished by requiring compliance to FAR Part 25 climb regulations.   As a result,

FAA Exemption No.  5146 was granted on February 20, 1990.

In 1992 REI petitioned for and was granted an amendment to FAA Exemption No. 5146.  Exemption No.

5146A was issued on August 21, 1992.

Current Petition:

Per 14 CFR 11.61(b) REI is submitting for an amendment to FAA Exemption No. 5146A to extend its

applicability to include the HBC model C90GT and C90GTi.

Per the requirements of 14 CFR 11.81:

(a) Nathan Lachendro

Program Manager, King Air &

Learjet Products

Raisbeck Engineering

4411 S. Ryan Way

Seattle, WA. 98178

(office) 206‐723‐2000

(cell) 206‐890‐9836

nate@raisbeck.com

(b) The existing exemption sought and was granted relief from the requirements of CAR 3.242 (b).  The

requested amendment to this exemption does not require a change to this relief.

NL‐12‐002
(c) REI seeks amendment to existing Exemption No. 5146A in order to extend the applicability to include

the HBC model C90GT and C90GTi. This will allow REI’s current gross weight increase STCs to be

compatible with these aircraft.   

The existing exemption references Beech models B90, C90, C90A and E90.  Since the issuance of this

exemption HBC has introduced the C90GT and C90GTi as new models under Type Certificate Data

Sheet (TCDS) 3A20.  These newer models are C90A airframes equipped with new engines, avionics

and interior.   

The C90GT and C90GTi along with all of the 90 models listed in the exemption share the same

certification basis for CAR 3.242(b). The differences of the C90GT and C90GTi do not affect the

requirement of the exemption letter to incorporate part 25 climb requirements.   

It is important to note that the differences between the B90, C90, C90A and E90 are primarily engine

type and weight limitations. The C90GT and C90GTi therefore do not change the certification

assumptions as it relates to the applicability of the exemption.

(d) The grant of the existing exemption was found to be in the public’s interest.  The addition of the

C90GT and C90GTi would also be in the public’s interest considering they are the current production

models and by denying their applicability would incur the same undue consequences, namely and

verbatim:

(1) Incorporation of a fuel jettisoning system, by itself, does not guarantee that a specific takeoff will

have go‐around capability in event of an immediate return to the field whereas requiring specific

climb gradients will assure this capability.  

(2) Dumping of fuel is not environmentally acceptable from the viewpoints of a wasted resource and

air/ground/water pollution. Transport aircraft experience has shown that fuel dumping is not

necessary to assure safety of the flight.

(3) The costs to the public associated with increasing the utility of the airplane (increased payload‐

range) will be substantially lower without a fuel jettisoning system.

(4) The safety concerns in event of an inadvertent fuel dump far outweigh the potential benefit of

protecting the airplane from an overweight landing in the event of an immediate return to the

takeoff field.

(e) The grant of the existing exemption was found not to affect safety.  The addition of the C90GT and

C90GTi would also not affect safety since those aircraft are essentially identical in type design,

construction and certification basis as the earlier models.  

(f) “By letter dated December 27, 2011, Mr. Nathan Lachendro, on behalf of Raisbeck Engineering (REI),

4411 S. Ryan Way, Seattle, WA 98178, petitioned for an amendment to extend the applicability for

relief to CAR 3.242 (b) to include the model C90GT and C90GTi.  REI is seeking applicability of this

amendment for application of these aircraft models to its current supplemental type certificates.”
Finally, REI seeks relief from the FAA request for public comment per 14 CFR 11.45 (e).  14 CFR 11.87

provides specific circumstances in which the FAA may not decide to request public comments.  REI feels

the current request supports each of these instances, specifically:

(a) Whether granting your petition would set a precedent.

Since this would be the second amendment to a previously granted petition, no precedent is

being set.

(b) Whether the relief requested is identical to exemptions granted previously.

The request is for applicability of additional aircraft models to a previously granted exemption.

(c) Whether our delaying action on you petition would affect you adversely.

Future sales of REI STCs are directly affected with each passing week.

(d) Whether you filed your petition in a timely manner.

This petition is being filed within one week of notification from the Seattle ACO that REI would

need to apply for amendment in order to support a current STC project at the ACO.

If you have any questions about this petition please feel free to contact me

Sincerely,

Nathan Lachendro

Program Manager, King Air &

Learjet Products

Raisbeck Engineering

cc: Mr. Chris Parker, Seattle Aircraft Certification Office

James Raisbeck, REI

Erik Christofferson, REI

Bill Lally, REI

Document Control, REI

attachments:    

FAA Exemption No. 5146, issued February 20, 1992

FAA Exemption No. 5146A, issued August 21, 1992