Airworthiness Directive for Cabin Heater System for Great Lakes Aircraft Header Information DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 39 Amendment 39-3024; AD 76-07-12 Airworthiness Directives; BENDIX IGNITION SWITCHES: Applies To All Aircraft Employing Magnetos and Using Bendix Ignition Switches PDF Copy (If Available): Preamble Information DATES: Effective August 30, 1977 Regulatory Information 76-07-12 BENDIX IGNITION SWITCHES: Amendment 39-2575 as amended by Amendment 39-3024. Applies to all aircraft employing magnetos and using Bendix ignition switches listed in the table below except switches identified by four digit date code (new) adjacent to the model number or a white dot (modified) on the support plate adjacent to the Bendix logo. Bendix Switches Rotary Action, Key or Lever Actuated Switch Function Bendix (series) Part Numbers Twist-to-Start 10-357XXX, 10-126XXX Twist-to-Start/Push-to-Prime 10-357XXX, 10-126XXX Push-to-Start 10-357XXX, 10-126XXX, 10-157XXX Compliance required as indicated: 1. For switches subject to this AD, conduct the following checks within the next 100 hours' time in service and each 100 hours thereafter to detect possible switch malfunction: (a) Observing regular ground run-up procedures, allow the engine to reach operating temperatures and perform a normal magneto check. (b) With the engine at normal idle, rotate the switch key or lever through the "OFF" detent to the extreme limit of its travel in the "OFF" direction. (c) If the engine stops firing, this indicates an airworthy switch. (d) If the engine continues to run with the switch in the extreme "OFF" direction indicating a malfunctioning switch, prior to the next flight accomplish Part III outlined in Bendix Service Bulletin No. 583, dated April 1976, for Repair and Replacement or use an alternate method approved by Chief, Engineering and Manufacturing Branch, Eastern Region. 2. The aircraft may be flown in accordance with FAR 21.197 to a place where these modifications can be accomplished. 3. The checks required by this AD may be performed by the pilot. 4. Upon submission by an operator with substantiating data, an FAA Maintenance Inspector subject to prior approval of the Chief, Engineering and Manufacturing Branch, FAA Eastern Region may adjust the compliance times specified in this AD if the request contains substantiating data to justify the increase for the operator: (NOTE: If the engine continues to run when complying with paragraph 1 and repair or replacement cannot or will not be accomplished immediately, the magneto (primary circuit) should be grounded in accordance with Bendix Service Bulletin No. 583, dated April 1976.) Amendment 39-2575 was effective April 14, 1976. This amendment 39-3024 is effective August 30, 1977. Back to the Great Lakes Ad page.

Airworthiness Directive for Cabin Heater System

Federal Register Information

Header Information
DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

Amendment 39-5460; AD 78-26-10 R1

Airworthiness Directives; Great Lakes Model 2T-1A-1 and 2T-1A-2 Airplanes

Preamble Information
AGENCY: Federal Aviation Administration, DOT

DATES: Effective December 17, 1986.

Regulatory Information

78-26-10 R1 GREAT LAKES: Amendment 39-3384 as amended by Amendment 39-5460. Applies to Models 2T-1A-1 and 2T-1A-2 airplanes.

COMPLIANCE: Required as indicated unless already accomplished.

To preclude contamination of cockpit heater air with carbon monoxide, accomplish the following:

A) Within the next 25 hours time-in-service after the effective date of this AD:

1. Determine if the airplane is equipped with a P/N 50146 cockpit heater system and, if not, make an entry in the airplane's maintenance record that the airplane complies with Paragraph A)1 and that further compliance with this AD is not required. This determination and maintenance record entry may be made by the owner or holder of a valid pilot certificate.

2. If the airplane is equipped with a P/N 50146 cockpit heater system, prior to further flight, install a revision in the walk around inspection (Section II C. 2) of the Flight Manual adding an inspection of the exhaust system hanger (Figure 1 of this AD).

3. If the airplane is equipped with a P/N 50146 cockpit heater system, prior to further flight, and within each 25 hours time-in-service thereafter:

a) Remove the cowl to gain access to the engine installation.

b) Disconnect the two cockpit air heater ducts from the heater shroud and remove the shroud.

c) Visually inspect the support plates of the heat exchanger at both ends for cracks between the five tube cluster.

d) If no cracks are found, return the heat exchanger to service.

e) If cracks are found, either replace the heat exchanger system with an airworthy part or, in the alternative, comply with Paragraph B) of this AD.

B) Remove the optional heat exchanger system and:

1) Install P/N 50126-1 stack assembly on all aircraft and P/N 50172-1 shield on aircraft equipped with IO-360-BIF6 and AEIO-360-BIG6 engines using QS100-M32W or equivalent clamps.

2) Block existing cockpit heat control valve in closed position by safety wiring control arm to adjacent aircraft structure.

3) Block the cockpit air supply opening in the left vertical engine cooling baffle per AC 43.13 1 and 2.

4) Remove Aircraft Flight Manual Revision specified in Paragraph A)2 of this AD (if installed).

C) The actions and inspections specified in paragraphs A)2. and A)3. of this AD may be discontinued upon either removal of the P/N 50146 cockpit heater system per paragraph B) of this AD, or replacement of the P/N 50146 cockpit heater system with a different FAA approved cockpit heater system.

D) Any equivalent method of compliance with this AD must be approved by the Manager, Boston Aircraft Certification Office, Federal Aviation Administration, New England Region, 12 New England Executive Park, Burlington, Massachusetts 01803.

Great Lakes Aircraft Company (GLAC) Service Bulletin No. 9, dated November 17, 1978, or later revisions, pertain to portions of this subject.

This amendment revises AD 78-26-10, Amendment 39-3384, which became effective January 4, 1979.
This amendment, 39-5460, becomes effective on December 17, 1986.

FIGURE 1
AIRPLANE FLIGHT MANUAL REVISION

(AD 78-26-10 requires this revision to remain in the below designated airplane flight manual when the airplane is equipped with the optional P/N 50146 cockpit heater system.

MODEL N S/N

In addition to the presently specified preflight procedures, prior to each flight:
1. Inspect the left engine exhaust tail pipe hanger for deformation or failure.
2. If found failed, the hanger must be repaired prior to further flight.

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