Subject: FLIGHT DECK OBSERVER SEAT 

AND ASSOCIATED EQUIPMENT

Date: 6/3/04 

Initiated by: AFS-220 

AC No: 

Change:

120-83 

1. PURPOSE. To provide guidance for Title 14 of the Code of Federal Regulations (14 CFR) 

parts 121, 125, and 135 certificate holders for obtaining a Federal Aviation Administration (FAA) 

finding regarding the operational safety/suitability of the Flight Deck Observer Seat and Associated 

Equipment. This guidance may be used to comply with part 121, section 121.581(a), part 125, 

section 125.317(b), and part 135, section 135.75(b). The FAA Administrator has delegated the 

responsibility for determining operational suitability of Flight Deck Observer Seats to the FAA 

Flight Standards Service. 

2. RELATED 14 CFR SECTIONS. 

a. Part 25, Subpart D - Design and Construction. Section 25.785. Part 25, Subpart C – 

Structure. Sections 25.561, 25.562. 

b. Part 121, Subpart T – Flight Operations. Section 121.581. 

c. Part 125, Subpart J – Flight Operations. Section 125.317. 

d. Part 135, Subpart B – Flight Operations. Section 135.75. 

3. DEFINITIONS. For purposes of this document, these terms are defined as follows: 

a. Administrator. The Federal Aviation Administrator or any person to whom the 

Administrator has delegated authority in the matter concerned. 

b. Flight Deck Observer Seat. The Flight Deck Observer Seat (henceforth referred to as 

“observer seat”) designated by the Administrator located in or adjacent to the flight deck. It does 

not include any passenger seat. If the airplane has more than one observer seat installed on the 

flight deck, it means the seat that is designated by the Administrator for the purposes of 

conducting en-route inspections. 

c. Flight Deck or Cockpit. While only the term “flight deck” is used in this AC, these 

terms are used in 14 CFR and in other publications interchangeably. For the purpose of this 

document, “flight deck” and “cockpit” have the same meaning. 
AC 120-83 6/3/04 

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4. RELATED READING MATERIAL. 

a. Related Advisory Circulars (AC). AC 25-17, Transport Airplane Cabin Interiors 

Crashworthiness Handbook. 

NOTE: You can download many ACs free of charge from the following FAA 

public Web site: 

www.faa.gov

Click on Regulations & Policies 

Click on Advisory Circulars 

Free ACs may be obtained by mail from: 

U.S. Department of Transportation 

Subsequent Distribution Office, M-30 

Ardmore East Business Center 

3341 Q 75th Ave. 

Landover, MD 20785 

b. Related Technical Standard Orders (TSO). 

(1) TSO C22(a-g), Safety Belts. 

(2) TSO C39(a-b), Aircraft Seats and Berths. 

(3) TSO C114, Torso Restraint Systems. 

(4) TSO C127, Rotorcraft and Transport Seating Systems. 

NOTE: You can obtain TSO from the following FAA public Web site: 

www.faa.gov 

Click on Regulations & Policies 

Click on Guidance 

Click on Regulatory & Guidance Library 

Click on Technical Standard Orders (TSO) and Index 

5. OPERATIONAL CONSIDERATIONS AND STANDARDS. The observer seat must meet 

all the requirements for occupancy as prescribed by the pertinent sections of part 25. However, 

because the Type Design Certification Basis of the airplanes into which observer seats are 

installed vary widely, newer airplanes may have more stringent requirements applied to observer 

seats than older airplanes. If necessary, the resources noted in paragraphs 2 and 4 should be used 
6/3/04 AC 120-83 

Par 5 Page 3

as the basis for determining if the requirements of part 25 have been met. The following 

standards shall be met: 

a. Observer Seat Location. The location of the observer seat should allow the observer a 

clear unobstructed view of the aircraft instrument panel to determine the pilot’s compliance with 

operating rules and standards. The location must not impede flight deck crewmember or 

observer emergency egress routes from the flight deck to the cabin or flight deck windows (if 

they are used as escape routes) and flight deck escape hatches. The observer seat location must 

account for both tall and short individuals occupying it, based on use of existing part 25 height, 

weight, and human factors requirements. The observer seat location needs to provide adequate 

leg and foot clearance to prevent leg impingement with adjoining structure or other crew seats 

during crew seat adjustments. 

b. Observer Seat Foot Rest. The observer seat will be occupied for extended periods of 

time, therefore human factors associated with foot placement must be considered. The 

occupant’s feet need to be able to rest on a solid surface and to have some freedom of movement 

during flight. If the occupant’s feet cannot rest on a solid surface, then installation of footrests or 

fixed or retractable footrest bars should be considered. Foot placement can be extremely critical 

if an observer seat location permits the occupant’s feet to be placed on the flight deck center 

pedestal area and/or the flight deck controls or systems. Consideration should be given to 

installing foot restraint bars to prevent foot migration to critical airplane controls. 

c. Observer Seat Comfort. The observer seat may be occupied for extended periods of 

time. Observer seat comfort considerations should be addressed, such as padding, thickness, 

foam density, firmness, etc., as called for under the seat TSO, AC, and regulations referenced 

above. In addition, observer seat comfort evaluations should be conducted under actual flight 

conditions and should consider the length of time the seat is occupied by an observer. 

d. Visibility from Observer Seat. The observer seat should also provide a clear view 

through the flight deck windows with the observer seated fully upright. The observer should be 

able to assist the flightcrew in seeing other aircraft during all phases of flight. 

e. Observer Seat Safety Harness Systems. The observer seat Torso Restraint or Safety 

Harness System should meet the requirements of part 25. For example, the observer seat should 

have the same “five-point” quick release harness (lap, crotch, and two shoulder belts) as the other 

flight deck crewmembers to restrain movement during turbulence or impact. The restraint 

system should allow the observer seat occupant the same flexibility to remove shoulder harnesses 

without removal of the seatbelt during certain phases of flight. Shoulder harness and belt 

restraint system comfort should be evaluated under actual flight conditions. 

f. Oxygen. The observer seat should have the same quick don type oxygen mask and smoke 

goggles as the other flight deck crewmembers. The oxygen mask must be located within easy 

reach while seated and be able to be donned in 5 seconds. The oxygen mask must provide for 

communications with the flight and cabin crew. All 14 CFR requirements for Protective 

Breathing Equipment (PBE) should be addressed and evaluated under actual flight conditions.
AC 120-83 6/3/04 

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g. Communications. The observer seat should have a dedicated communications panel that 

allows the observer to listen to the flight and cabin crewmembers and all other channels of 

communications that are used by flight crewmembers. This includes, but is not limited to, 

communication with ground service personnel, flight attendants, and all radio communication. 

The observer seat should be located so that the occupant has access to a standard headset, and the 

location of the headset receptacle must be within easy reach while seated. All 14 CFR 

communications requirements for PBE should be addressed and evaluated. 

h. Lighting. The observer seat should have a dedicated light available that can be directed 

(pointed) and dimmed while seated. The on/off dimmer switch should be easily accessible while 

seated. 

i. Ventilation. The observer should have dedicated fresh airflow available through an 

“eyeball” or similar outlet. Control of the airflow should be within easy reach while seated. 

j. Safety and Security. The observer seat should be designed so that it cannot be retracted 

while seated. Downward collapsing observer seats that employ suspension type hook 

arrangements are not desirable where inadvertent movement of the locking devices could cause 

the observer seat to collapse. Observer seats should not be designed with sharp edges or finger 

entrapment locations. Placarding of instructions for observer seat deployment and stowage 

should be provided for observer seats whose operation is not obvious. Observer seat release and 

stowage control handles should be identifiable with a contrasting color to the general 

background. 

6. REQUEST FOR OPERATIONAL SAFETY/SUITABILITY DETERMINATION. 

Requests for an FAA finding of the operational safety/suitability of observer seat installations, 

for the purpose of meeting the requirements of section 121.581(a), section 125.317(b), or 

section 135.75(b), should be sent to the appropriate FAA Flight Standards Aircraft Evaluation 

Group (AEG) at the following address: 

Federal Aviation Administration 

Aircraft Evaluation Group, SEA AEG 

1601 Lind Ave. S.W. 

Renton, WA 98055-4056 

Aircraft Evaluation Group, LGB AEG 

3960 Paramount Boulevard 

Lakewood, CA 90712-4137 

Aircraft Evaluation Group, MKC AEG 

DOT Building, 901 Locust 

Kansas City, MO 64106-2641 
6/3/04 AC 120-83 

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a. Requests for observer seat finding of operational safety/suitability should include evidence 

that the observer seat has been certified for occupancy in accordance with the requirements of 

part 25 and is part of the original type certificate, amended type certificate, or supplemental type 

certificate. An installation conformity compliance check of the observer seat should be 

accomplished prior to the FAA ground and flight evaluations. Requests should include evidence 

that the Instructions for Continued Airworthiness have been included as a part of the observer 

seat installation certification process. 

b. In the event that the design of the observer seat usage requires preparation by the observer 

prior to use, such as deployment and stowage, the evaluation request should include appropriate 

preparation procedures, recommended qualification/training requirements, and proposed 

maintenance and operational actions to be taken in the event that the observer seat becomes 

inoperative. 

c. The evaluating AEG will complete a report on the operational safety/suitability evaluation 

including any limitations regarding use of the observer seat. This report should be referenced in 

the applicable type certificate or supplemental type certificate data sheet. Any limitations on the 

observer seat should be addressed in the Airplane Flight Manual and placarded on, or adjacent to, 

the seat. 

James J. Ballough 

Director, Flight Standards Service