11/17/2011 

 

APPENDIX 1. 

PARTIAL LIST OF FUNCTIONAL HAZARD ASSESSMENT (FHA) FOR CONSIDERA

TO MEET 14 CFR PART 23 REQUIREMENTS FOR IFR CLASS I AIRPLANES

*Note: This table is only intended to be a guide and is not a certification checklist since it may not include all the information necessary for an FHA oairplanes with its various functions and its intended use. This partial FHA does not reflect considerations needed to properly develop FHA. See parag

subparagraphs for more complete guidance. R = Reserved, intentionally left blank. 

A1-1 

Aircraft Function 

Classification of Failure Conditions Analysis Consideration 

Total Loss of Function 

Loss of Primary Means of Providing Function 

Misleading and/or Malfunction Without Warning 

Display of attitude information to control roll and pitch 

Catastrophic Major Catastrophic For electronic displays, dual independent attitude systems 

requirements for 14 CFR part 23, §§ 23.1301, 23.1309, & with less than 10 passengers and for conventional mechanielectromechanical systems. A single attitude display meetrequirements to operate under IFR. If the certification basAmendment 23-43 or later, two independent power source§ 23.1331. The requirement for two power sources in § 23applicable for pitot-static pneumatic systems. Partial paneused in some cases where it has been historically shown to Credit (mitigation) may be given for automatic flight contrsystem can maintain stable attitude independent of the prim

Display of directional heading information 

Major Minor Major A hazardously misleading heading is usually when the acc

than 10 degrees on the primary heading instrument and it iAssumes installation of a single stabilized heading system stabilized magnetic compass to operate under IFR for 14 Ccertification basis includes Amendment 23-43 or later, two sources are required by § 23.1331. The requirement of two § 23.1331 are not applicable for pitot-static pneumatic systassumed to be operating. See AC 23-17C for additional in
11/17/2011 

 

APPENDIX 1 (CONTINUED) 

*Note: This table is only intended to be a guide and is not a certification checklist since it may not include all the information necessary for an FHA oairplanes with its various functions and its intended use. This partial FHA does not reflect considerations needed to properly develop FHA. See parag

subparagraphs for more complete guidance. R = Reserved, intentionally left blank. 

A1-2 

Aircraft Function 

Classification of Failure Conditions Analysis Consideration 

Total Loss of Function 

Loss of Primary Means of Providing Function 

Misleading and/or Malfunction Without Warning 

Display of altitude information 

Hazardous Minor Catastrophic For electronic displays, dual independent altitude systems 

for 14 CFR part 23, §§ 23.1301, 23.1309, & 23.1311 and fanalog electromechanical systems. A single altitude displarequirements to operate under IFR. If the certification basor later, two independent power sources are required by § two power sources of § 23.1331 are not applicable for pitoExisting single static systems that are heated have been hissimilarity and may be used for programs that have certifica23-42. If a single or dual air data computer is used, it musAC with respect to safety and DAL. 
11/17/2011 

 

APPENDIX 1 (CONTINUED) 

*Note: This table is only intended to be a guide and is not a certification checklist since it may not include all the information necessary for an FHA oairplanes with its various functions and its intended use. This partial FHA does not reflect considerations needed to properly develop FHA. See parag

subparagraphs for more complete guidance. R = Reserved, intentionally left blank. 

A1-3 

Aircraft Function 

Classification of Failure Conditions Analysis Consideration 

Total Loss of Function 

Loss of Primary Means of Providing Function 

Misleading and/or Malfunction Without Warning 

Display of airspeed information 

Major. May be Hazardous for higher performance airplanes. 

Minor Major. 

May be hazardous or catastrophic for higher performance airplanes. 

For electronic displays, dual independent airspeed systems 

requirements for 14 CFR part 23, §§ 23.1301, 23.1309, & conventional mechanical or analog electromechanical systdisplay meets 14 CFR part 91 requirements to operate undcertification basis includes Amendment 23-43 or later, two sources are required by § 23.1331. The two power sources applicable for pitot-static pneumatic systems. Classificatiooverspeed and underspeed airspeed alerting is acceptable (provided by inherent aerodynamic qualities or independenotherwise, loss of function, malfunction, or misleading of iHazardous. It may be catastrophic when combined with thor overspeed warning functions. Assumes no vertical speesingle pitot static systems that are heated have been historion similarity and may be used for programs that have certiAmendment 23-42. If a single or dual air data computer is requirements of this AC with respect to safety and DAL. 

Display of Flight Path Vector 

Minor R Major Providing the other normal cues remains for primary flight 

sensor should remove the flight path vector. The pilot shouother displays. Misleading indication could cause the pilomaneuver the aircraft using erroneous guidance informatio

Display of rate-ofturn information Minor Minor Minor Rate-of-turn display is generally required to operate under 

requirements unless a third attitude is installed. If the certiAmendment 23-43 or later, two independent power sourcemisleading rate-of-turn information is consider to be Minoattitude display. 

Display of slip-skid information 

Minor Minor Minor R 
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APPENDIX 1 (CONTINUED) 

*Note: This table is only intended to be a guide and is not a certification checklist since it may not include all the information necessary for an FHA oairplanes with its various functions and its intended use. This partial FHA does not reflect considerations needed to properly develop FHA. See parag

subparagraphs for more complete guidance. R = Reserved, intentionally left blank. 

A1-4 

Aircraft Function 

Classification of Failure Conditions Analysis Consideration 

Total Loss of Function 

Loss of Primary Means of Providing Function 

Misleading and/or Malfunction Without Warning 

Display of time information 

Minor Minor Minor R 

Display of primary navigation information 

Major Major. 

Minor, if two navigation systems are installed. 

Major for CAT I ILS. Hazardous or major depending on type of WAAS operations. 

Two navigation systems are generally installed to support required for 14 CFR part 91 operations. Dual ILS receiverrequired with single antenna for part 91 operations. See Aon WAAS operations. 

Display of navigation information on MFD 

Minor R Minor Pilot should cross check with the course deviation indicato

Weather displays for situation awareness 

Minor Minor Minor Pilot is responsible to use standard procedures. It is used f

operation and is not intended for tactical maneuvering. 

Terrain Awareness and Warning System (TAWS) 

Minor R Major The loss of that system should be no greater than 10-3 per a

possibility of misleading information on the display due to should be no greater than 10-4 per average flight hour. For 

development assurance level should be at least to Level C or an acceptable alternative approved by the FAA. For Cladevelopment assurance level should be at least to Level D and visual annunciations are independent of the terrain disand visual annunciations are integrated on the displays, the C. NOTE: A terrain display is not mandatory for Class B more information. 
11/17/2011 

 

APPENDIX 1 (CONTINUED) 

*Note: This table is only intended to be a guide and is not a certification checklist since it may not include all the information necessary for an FHA oairplanes with its various functions and its intended use. This partial FHA does not reflect considerations needed to properly develop FHA. See parag

subparagraphs for more complete guidance. R = Reserved, intentionally left blank. 

A1-5 

Aircraft Function 

Classification of Failure Conditions Analysis Consideration 

Total Loss of Function 

Loss of Primary Means of Providing Function 

Misleading and/or Malfunction Without Warning 

Communication Minor. 

Total loss of navigation and communication is Hazardous. 

Minor Major, if data link. 

Otherwise, Minor. 

Future installations may use data link for primary function

Traffic information for situation awareness 

Minor Minor Minor to Major 

depending on the intended function of the alert warning or caution signal. 

Pilot is responsible to use standard “see and avoid proceduan approved substitute for traffic avoidance. See the appliadditional guidance. 

Mode A or C Transponder 

Minor R Minor to Major 

depending on the intended function of signals from the transponder. 

Air traffic control may receive misleading or loss of airplawhich increases their workload. An incorrect resolution adworkload in another aircraft. See the applicable AC and T

Display of radio altitude information

Minor R Minor Not required for 14 CFR part 91 operations, Category I IL

other equipment that depends upon radio altimeter. 
11/17/2011 

 

APPENDIX 1 (CONTINUED) 

*Note: This table is only intended to be a guide and is not a certification checklist since it may not include all the information necessary for an FHA oairplanes with its various functions and its intended use. This partial FHA does not reflect considerations needed to properly develop FHA. See parag

subparagraphs for more complete guidance. R = Reserved, intentionally left blank. 

A1-6 

Aircraft Function 

Classification of Failure Conditions Analysis Consideration 

Total Loss of Function 

Loss of Primary Means of Providing Function 

Misleading and/or Malfunction Without Warning 

Display of vertical speed information

Minor R Minor or Major. Not required for most 14 CFR part 91 operations. May be 

required by the operational requirements of parts 91 (Categconsidered required equipment essential to safe operation. 

Display of flight guidance commands (Category I operation) 

Minor R Major Not required for 14 CFR part 91 operations, Category I IL

autopilot or flight director is required. Minor for loss of flCategory I operations providing the other normal cues reminformation. Loss of the sensor should remove the guidanrecognize it and use other displays. Misleading indication temporary maneuver the airplane if using erroneous guidan

Autopilot Minor, with 

warning. Major, without warning. 

R Major, single axis 

and limited authority. Hazardous, multiaxis and limited authority. Catastrophic, if authority is unlimited. 

Malfunction effects of autopilot hardovers are very dependinstallation details. Maximum inputs (hardovers) or (slowcontrol surfaces should not exceed aircraft structural limits23.1329 for additional information. 

Autopilot guidance or flight director cue on display 

Minor Minor Major for pitch. 

Minor for roll. 

Pilot must monitor autopilot operation and disconnect autopromptly. May cause go around and reductions in safety m
11/17/2011 

 

APPENDIX 1 (CONTINUED) 

*Note: This table is only intended to be a guide and is not a certification checklist since it may not include all the information necessary for an FHA oairplanes with its various functions and its intended use. This partial FHA does not reflect considerations needed to properly develop FHA. See parag

subparagraphs for more complete guidance. R = Reserved, intentionally left blank. 

A1-7 

Aircraft Function 

Classification of Failure Conditions Analysis Consideration 

Total Loss of Function 

Loss of Primary Means of Providing Function 

Misleading and/or Malfunction Without Warning 

Autopilot, inability to disengage with A/P disconnect switch 

Major Major Major The pilot is assumed to overcome the servo slip clutches in 

to maintain control of aircraft. Minor if the circuit breaker readily available in flight. 

Electrical-Electronic primary powered flight controls 

Catastrophic Minor Hazardous to 

catastrophic 

Assumes redundant electrical/electronic primary flight conreversion that provide independent control for each axis. Hchannel on the lateral or longitudinal axis. Some fly-by-wire system designs may incorporate many sseverity of the loss of a single channel. They may have thchannels for pitch and roll, so the loss of one has little funbe maintained with a single channel, although normally wiprotections. Additionally there may be mitigating factors which can reduce hazards. 

Stability augmentation 

Variable Minor Variable It needs to be evaluated on a case-by-case basis since it de

handling characteristics when installed and required to meflight handling requirements. 

Stick pusher Hazardous, if loss 

is not annunciated. Major if the stall warning is functioning. Minor, if failure is annunciated and the stall warning is functioning. 

Minor Catastrophic to 

hazardous if the pilot is able to override or able for quick disconnect. 

The system is installed to protect against a hazardous stall unrecoverable catastrophic condition such as a deep stall. prevent single-failure modes. Stick pusher malfunction wicatastrophic depending on phase of flight and system attribstick pusher may be considered and pilot procedures may mcondition. 
11/17/2011 

 

APPENDIX 1 (CONTINUED) 

*Note: This table is only intended to be a guide and is not a certification checklist since it may not include all the information necessary for an FHA oairplanes with its various functions and its intended use. This partial FHA does not reflect considerations needed to properly develop FHA. See parag

subparagraphs for more complete guidance. R = Reserved, intentionally left blank. 

A1-8 

Aircraft Function 

Classification of Failure Conditions Analysis Consideration 

Total Loss of Function 

Loss of Primary Means of Providing Function 

Misleading and/or Malfunction Without Warning 

Stick shakers with Stall warning 

 Major without other means of stall warning and unannunciated loss of stall warning. Minor for annunciated loss of stall warning 

Major without other means of stall warning and unannunciated loss of stall warning. Minor for annunciated loss of stall warning 

Major without other means of stall warning. 

Assumes that inherent airplane characteristics do not exist sclose to stall (for example, stick force changes, buffeting, et

Trim control Minor Minor Major, if manual 

trim. Catastrophic or hazardous for electrical. 

Studies have shown trim runaways are not a significant probcorrective action. Major, for trim runaways if there is a trimHazardous or catastrophic for trim runaways without a failutrim authority and phase of flight. 

Gear control Major Minor Major RBrake control Major, for 

airplanes  6,000 lbs. Minor, for airplanes  6,000 lbs. 

Major. Could be minor, if thrust reversers are installed. 

Major Electronic anti-skid and brake systems can cause significant 

they malfunction under adverse conditions due to asymmetrbraking loss is not as significant and can be reviewed on a c

Display of trim indications 

Minor Minor Variable Each airplane has to be reviewed on a case-by-case basis. T

phase of flight before takeoff. After takeoff, the trim positiobecause the pilot will adjust the trim position to relieve the c

Display of gear indications 

Minor R Minor R 
11/17/2011 

 

APPENDIX 1 (CONTINUED) 

*Note: This table is only intended to be a guide and is not a certification checklist since it may not include all the information necessary for an FHA oairplanes with its various functions and its intended use. This partial FHA does not reflect considerations needed to properly develop FHA. See parag

subparagraphs for more complete guidance. R = Reserved, intentionally left blank. 

A1-9 

Aircraft Function 

Classification of Failure Conditions Analysis Consideration 

Total Loss of Function 

Loss of Primary Means of Providing Function 

Misleading and/or Malfunction Without Warning 

Display of fuel level indication 

Minor Minor Minor Pilot is required to calculate fuel range and endurance duri

operations. 

Display of powerplant indication tachometer 

Minor Minor Minor Assumes fixed pitch propeller and reciprocating engine; ot

will maintain the engine r.p.m. Turbofan and turbojet eng

inflight restart capability. Refer to 14 CFR part 23, § 23.1

Display of powerplant Cylinder Head Temperature (CHT) 

Minor Minor Minor Assumes a CHT indicator is required. Refer to 14 CFR 

part 23, § 23.1305. 

Display of powerplant indication coolant temperature 

Minor Minor Minor Refer to 14 CFR part 23, § 23.1305. 

Display of powerplant indication oil pressure 

Minor Minor Minor Assumes oil temperature is used as a backup. 

Display of powerplant indication oil temperature 

Minor Minor Minor Assumes oil pressure is used as a backup. 
11/17/2011 

 

APPENDIX 1 (CONTINUED) 

*Note: This table is only intended to be a guide and is not a certification checklist since it may not include all the information necessary for an FHA oairplanes with its various functions and its intended use. This partial FHA does not reflect considerations needed to properly develop FHA. See parag

subparagraphs for more complete guidance. R = Reserved, intentionally left blank. 

A1-10 

Aircraft Function 

Classification of Failure Conditions Analysis Consideration 

Total Loss of Function 

Loss of Primary Means of Providing Function 

Misleading and/or Malfunction Without Warning 

Display of powerplant indication manifold pressure 

Minor Minor Minor Assumes backup use of CHT, Engine Gas Temperature (E

readings if installed. 

Display of powerplant air inlet temperature 

Minor Minor Minor R 

Display of powerplant indication fuel pressure 

Minor Minor Minor R 

Display of powerplant indication fuel flow 

Minor Minor Major Manifold pressure and r.p.m. or torque indications can be u

to control power until a safe landing can be made. 

Display of powerplant fire warning 

Major Major Major Required for commuter category and part 23 turbojet powe

conditions. Part 23 airplanes usually have one fire warnin

Display of powerplant indication thrust 

Minor Minor Hazardous System is not normally used in part 23 airplanes. Torque, 

EGT, or Turbine Inlet Temperature (TIT), fuel flow, and r
11/17/2011 

 

APPENDIX 1 (CONTINUED) 

*Note: This table is only intended to be a guide and is not a certification checklist since it may not include all the information necessary for an FHA oairplanes with its various functions and its intended use. This partial FHA does not reflect considerations needed to properly develop FHA. See parag

subparagraphs for more complete guidance. R = Reserved, intentionally left blank. 

A1-11 

Aircraft Function 

Classification of Failure Conditions Analysis Consideration 

Total Loss of Function 

Loss of Primary Means of Providing Function 

Misleading and/or Malfunction Without Warning 

Display of powerplant thrust reverser position 

No effect No effect Major No certification credit is given for enhanced performance 

installed. 

Thrust reversal Minor Minor Variable 

(inadvertent deployment) 

No certification credit is given for enhanced performance installed. No credit can be given for a warning. 

Display of powerplant torque 

Minor Minor Major Misleading torque could affect takeoff performance. 

Display of powerplant propeller blade angle 

No safety effect No safety effect No safety effect System is not normally used in part 23 airplanes. Propelle

Electronic displays of significant powerplant parameters 

Minor to Hazardous 

R Hazardous Reversionary display is considered not available. If the ris

due to pilot mishandling can be mitigated by appropriate pof function may be major or minor. 

Visual warnings, cautions, and alerts 

R R R Failure conditions depend on the criticality of systems bein

required. 

Display of air temperature 

Minor R Minor R 
11/17/2011 

 

APPENDIX 1 (CONTINUED) 

*Note: This table is only intended to be a guide and is not a certification checklist since it may not include all the information necessary for an FHA oairplanes with its various functions and its intended use. This partial FHA does not reflect considerations needed to properly develop FHA. See parag

subparagraphs for more complete guidance. R = Reserved, intentionally left blank. 

A1-12 

Aircraft Function 

Classification of Failure Conditions Analysis Consideration 

Total Loss of Function 

Loss of Primary Means of Providing Function 

Misleading and/or Malfunction Without Warning 

Overspeed warning Minor Minor Minor Airspeed may be used as a backup to the overspeed warnin

landing. Crew recognizes conditions by other equipment a

Primary weather radar 

Minor to Major depended on the intended operations 

R Major The loss could be major when the equipment is required by 

Air Traffic guidance in some locations might not be availabweather information. It could be minor if there are appropr

Flight Information Service Weather 

Minor Minor Minor Normal operating procedures should states that the weather 

only as a strategic planning tool for pilot decision. 

Electronic Chart on the MFD 

Minor Major, if paperless cockpit. 

Minor, if backup available 

Major with ownship position. While we are not requiring any backup, we strongly recom

procedure section recommend that the pilot carry a paper bnecessary information to make a successful approach at theairport. In addition, the AFMS should contain emergency charts on the MFD. A backup to the electronic charts on thFlight Bag with charts, paper approach charts of the destinpilot simply make notes of minimums and all other necessasuccessful approach at their destination or alternate airportis shown, it is not considered the primary navigation displadisplay is required. 
11/17/2011 

 

APPENDIX 1 (CONTINUED) 

*Note: This table is only intended to be a guide and is not a certification checklist since it may not include all the information necessary for an FHA oairplanes with its various functions and its intended use. This partial FHA does not reflect considerations needed to properly develop FHA. See parag

subparagraphs for more complete guidance. R = Reserved, intentionally left blank. 

A1-13 

Aircraft Function 

Classification of Failure Conditions Analysis Consideration 

Total Loss of Function 

Loss of Primary Means of Providing Function 

Misleading and/or Malfunction Without Warning 

Aural warnings Major R Major Aural alerts tend to be reserved for required flight crew’s i

Failure conditions depend on the criticality of the system. other equipment and procedures. 

Electrical system indication 

Minor Minor Major Depends on crew reference and analysis. 

Vacuum pressure indication 

Minor Minor Major Provides an indication that flight instruments are operating 

Electrical power Catastrophic, if 

primary flight instruments require electrical power. 

Hazardous for IFR. Depends upon capability of secondary power system. 

Installation dependent 

Depends on electrical system loads and the criticality of th