13.3 Crew Resource Management (CRM) & Threat and Error Management (TEM)

Crew Resource Management (CRM) & Threat and Error Management (TEM)

Core Airline Transport Principle: Aviation accident investigations over six decades have demonstrated that the overwhelming majority of transport category accidents are rooted not in mechanical airframe failures, but in human factors breakdowns—loss of situational awareness, communication failures, authority gradient breakdowns, and flawed threat management. Crew Resource Management (CRM) and the Threat and Error Management (TEM) framework provide the operational discipline and non-technical skills required to anticipate threats, trap human errors, and prevent Undesired Aircraft States.

---

1. CRM Foundations & Core Flight Deck Competencies

Mandated under 14 CFR 121 Subparts N and O and detailed in FAA Advisory Circular AC 120-51E, Crew Resource Management is the effective utilization of all available resources—human hardware, software, information, and automation—to achieve safe and efficient flight operations.

+-----------------------------------------------------------------------------+
|                        THE FOUR PILLARS OF FLIGHT DECK CRM                  |
|                                                                             |
|   +---------------------------------+  +---------------------------------+  |
|   | 1. SITUATIONAL AWARENESS (SA)   |  | 2. WORKLOAD MANAGEMENT          |  |
|   | - Perception of elements        |  | - Task prioritization           |  |
|   | - Comprehension of meaning      |  | - Aviate, Navigate, Communicate |  |
|   | - Projection of future status   |  | - Shedding non-critical tasks   |  |
|   +---------------------------------+  +---------------------------------+  |
|   +---------------------------------+  +---------------------------------+  |
|   | 3. COMMUNICATION DYNAMICS       |  | 4. LEADERSHIP & FOLLOWERSHIP    |  |
|   | - Inquiry and Advocacy          |  | - Flat/open authority gradient  |  |
|   | - Assertiveness (PACE model)    |  | - Participatory decision making |  |
|   | - Closed-loop feedback / readback| - Constructive dissent / support  |  |
|   +---------------------------------+  +---------------------------------+  |
+-----------------------------------------------------------------------------+

The Three Levels of Situational Awareness (Endsley Model)

1. Level 1 — Perception: Accurately perceiving critical environmental cues, instrument indications, system states, and ATC instructions (e.g., detecting an uncommanded airspeed decay on final approach).
2. Level 2 — Comprehension: Synthesizing sensory data into an accurate mental model of current aircraft status (e.g., recognizing that the airspeed decay is caused by low-altitude windshear, not autothrottle lag).
3. Level 3 — Projection: Anticipating the future state of the aircraft and environment to initiate proactive intervention (e.g., anticipating that maintaining current pitch will trigger stick shaker within 3 seconds, requiring immediate go-around).

---

2. The Sterile Cockpit Rule (14 CFR 121.542 & 135.100)

Enacted following numerous fatal accidents caused by flightcrew distraction during taxi, takeoff, and approach, 14 CFR 121.542 establishes strict legal prohibitions on non-essential flight deck activities.

+-----------------------------------------------------------------------------+
|                 14 CFR 121.542 STERILE COCKPIT BOUNDARIES                   |
|                                                                             |
|   Altitude                                                                  |
|     ^                                                                       |
|     |   FLIGHT ABOVE 10,000 FT MSL (Excluding Cruise Below 10,000')         |
|     |   ===========================================================         |
|     |   * Non-essential operational conversation permitted.                 |
|     |   * Company administrative communications permitted.                  |
|     |                                                                       |
|   10,000 ft MSL ---------------------------------------------------         |
|     |   CRITICAL PHASES OF FLIGHT (STERILE COCKPIT MANDATORY)               |
|     |   ====================================================                |
|     |   * All ground operations (taxi-out, taxi-in, pushback).              |
|     |   * Takeoff roll, initial climb through 10,000 ft MSL.                |
|     |   * Descent through 10,000 ft MSL, approach, and landing roll.        |
|     v                                                                       |
|    0 ft (Surface)                                                           |
+-----------------------------------------------------------------------------+

Prohibited vs. Required Activities Under Sterile Cockpit

| Strictly PROHIBITED Below 10,000 ft | Legally REQUIRED & PERMITTED | | :--- | :--- | | | Engaging in non-essential casual conversation | Accomplishing normal checklists and flight control callouts | | Eating meals or drinking non-essential beverages | Communicating with ATC regarding clearances and traffic | | Reading non-operational literature (newspapers, magazines) | Executing emergency procedures and abnormal checklists | | Intercom chats with flight attendants regarding meal service | Receiving safety-critical cabin calls (fire, smoke, medical emergency) | | Personal electronic device use (texting, browsing) | Briefing the approach and runway exit strategy |

---

3. The Threat and Error Management (TEM) Model

Developed by the University of Texas Human Factors Research Project and adopted globally by ICAO and the FAA (AC 120-90), TEM recognizes that threats and errors are inevitable in complex socio-technical airline operations. Safety is achieved not by demanding zero human error, but by actively managing threats and trapping errors before they result in an incident.

+-----------------------------------------------------------------------------+
|                   THREAT AND ERROR MANAGEMENT (TEM) FLOW                    |
|                                                                             |
|   [ THREATS ]              [ FLIGHTCREW ERRORS ]     [ UNDESIRED AIRCRAFT   |
|   (External/Internal)      (Handling/Procedural/       STATES - UAS ]       |
|            |                Communication)                  |               |
|            v                       |                        v               |
|   +-----------------+              v               +-----------------+      |
|   | AVOID THREAT    |----->+---------------+------>| MITIGATE / EXIT |      |
|   | via Briefing &  |      | TRAP ERROR    |       | UAS via Go-     |      |
|   | SOPs            |      | via Cross-    |       | Around / Recov  |      |
|   +-----------------+      | check/Callout |       +-----------------+      |
|                            +---------------+                |               |
|                                                             v               |
|                                                    [ SAFE RECOVERY ]        |
|                                                    or ACCIDENT/INCIDENT     |
+-----------------------------------------------------------------------------+

Detailed Taxonomy of TEM Components

1. Threats (Events outside flightcrew direct control)

• Environmental Threats: Thunderstorms, microbursts, heavy crosswinds, contaminated runways, mountain wave turbulence, dense airport traffic, high-terrain departure corridors, unfamiliar airport layouts.
• Organizational / Airline Threats: Maintenance delays, Minimum Equipment List (MEL) operational restrictions, late gate changes, uncoordinated ground crews, tight turnaround schedules, dispatch flight plan errors, commercial pressure.

2. Flightcrew Errors (Actions or inactions leading to deviation)

• Handling Errors: Over-controlling flight surfaces, flying above/below approach speed ($V_{\text{REF}}$), flaring too high or landing long.
• Procedural Errors: Omitting a checklist item, failing to set barometric minimums, improper MCP mode selection, late flap/gear extension.
• Communication Errors: Inaccurate ATC readback, failing to challenge an incorrect altitude capture, ambiguous internal cockpit callouts.

3. Undesired Aircraft States (UAS)

A flightcrew-induced aircraft state that clearly increases operational risk (e.g., an unstabilized approach, altitude bust, lateral airway deviation, wrong taxiway alignment, speed decay near stall warning).

---

4. The Three Lines of Defense: Avoid, Trap, Mitigate

+-----------------------------------------------------------------------------+
|                   THE THREE TEM DEFENSE STRATEGIES                          |
|                                                                             |
|   Defense Level   Core Mechanism             Practical Airline Example      |
|   -------------   ------------------------   -------------------------      |
|   1. AVOID        Proactive avoidance of     Conducting a thorough threat-  |
|      Threat/Error hazards and errors         forward briefing; routing      |
|                   before they occur.         around severe convective cells.|
|   -------------   ------------------------   -------------------------      |
|   2. TRAP         Detecting and correcting   PM cross-checks MCP altitude   |
|      Error        an error before it         window and catches PF typing   |
|                   compromises safety.        FL330 instead of FL310.        |
|   -------------   ------------------------   -------------------------      |
|   3. MITIGATE     Actively recovering from   Initiating an immediate        |
|      UAS          an Undesired Aircraft      GO-AROUND when passing 1,000'  |
|                   State to restore margins.  AGL unstabilized in IMC.       |
+-----------------------------------------------------------------------------+

---

5. Communication Frameworks: Assertiveness & Standard Briefings

The PACE Model for Graduated Assertiveness

When the Pilot Monitoring (PM) or First Officer observes an unsafe condition or error committed by the Pilot Flying (PF) or Captain, the crewmember utilizes the standardized PACE inquiry ladder:

1. P — Probe: Non-threatening inquiry to draw attention ("Captain, what is our target altitude for this waypoint?").
2. A — Alert: Direct statement of the observed deviation ("Captain, we are 15 knots fast and above the glidepath.").
3. C — Challenge: Direct operational instruction ("Captain, we are unstabilized below 1,000 feet. You must go around now.").
4. E — Emergency Intervention: Physical takeover of flight controls if the captain fails to respond ("I have the flight controls; executing go-around.").

The Two-Challenge Rule

If a pilot makes two consecutive verbal challenges regarding an unsafe flight path or incapacitation without an appropriate verbal response or corrective action from the flying pilot, the monitoring pilot is legally mandated by airline SOP to assume immediate physical control of the aircraft.

Threat-Forward Briefing Structure

Modern airline transport briefings replace rote recitation with interactive, threat-forward planning:

• T — Threats: What is the single biggest threat on this departure/approach (e.g., gusty crosswind, short runway, high terrain, NOTAMs)?
• E — Error Trapping: What specific error are we most likely to commit in this environment?
• M — Mitigation: What concrete countermeasures will we implement (e.g., selecting maximum autobrakes, verbalizing 500-foot stabilization gates, planning immediate go-around)?