HASELL is a mandatory pre-maneuver safety checklist used in aviation before conducting aerobatics, spins, unusual attitude training, or any high-risk flight operation. This structured acronym ensures pilots systematically verify critical safety factors essential for maneuvering safety and emergency recovery.
Unlike general checklists, HASELL specifically addresses the unique hazards of operations beyond normal flight attitudes.
Why HASELL Checks Exists
Aircraft maneuvering near performance limits introduces elevated risks: spatial disorientation, structural stress, loss of control, and reduced recovery time. HASELL provides a standardized cognitive framework to mitigate these risks by forcing deliberate assessment of six non-negotiable elements before committing to the maneuver. Its use is mandated by flight training syllabi and aerobatic competition rules worldwide.
Breaking Down the HASELL Acronym
Each letter represents a life-critical verification:
- H – Height
- Purpose: Confirm sufficient altitude for maneuver entry, execution, recovery, plus safety buffer.
- Risk Mitigated: Controlled Flight Into Terrain (CFIT) during unexpected delays in recovery.
- Procedure:
- Calculate minimum recovery altitude for specific maneuver (consult POH)
- Add 50-100% buffer based on experience/environment
- Verify current altitude well exceeds total
- Critical Consideration: Density altitude significantly impacts climb performance during recovery.
- A – Airframe
- Purpose: Ensure aircraft configuration supports intended maneuvers.
- Risk Mitigated: Structural failure or degraded handling characteristics.
- Verification Points:
- Flaps UP (unless POH explicitly permits maneuvers with flaps)
- Landing gear UP and locked
- Speed brakes RETRACTED
- Trim set per maneuver requirements (usually neutral)
- Cowl flaps/auxiliary controls secured
- No known damage or service bulletins restricting maneuvers
- S – Security
- Purpose: Eliminate internal hazards from G-forces.
- Risk Mitigated: Projectile injuries or control interference.
- Verification Points:
- Shoulder harnesses TIGHTENED and LOCKED
- Lap belts secured
- Loose items stowed: Cameras, tablets, pens, water bottles secured
- Cockpit doors/windows LATCHED
- Baggage restrained within weight/balance limits
- E – Engine
- Purpose: Confirm reliable power delivery.
- Risk Mitigated: Power loss during critical phase.
- Verification Points:
- Oil pressure/temperature in GREEN range
- Fuel pressure stable
- CHT/EGT within limits
- RPM/manifold pressure normal
- Fuel selector on appropriate tank (fullest)
- Carb heat OFF (unless required for conditions)
- Mixture set correctly
- No abnormal vibrations or noises
- L – Location
- Purpose: Ensure spatial awareness for emergency options.
- Risk Mitigated: Airspace violations or unsuitable forced landing areas.
- Verification Points:
- Clear of terrain/obstacles (minimum 2,000′ buffer recommended)
- Within approved aerobatic practice area
- Outside restricted/prohibited airspace
- Identify nearest suitable landing sites
- Note wind direction for emergency approaches
- L – Lookout
- Purpose: Visually clear airspace before maneuvering.
- Risk Mitigated: Mid-air collision.
- Procedure:
- Execute 180° clearing turn while scanning all quadrants
- Visually check above, below, and blind spots
- Declare “CLEAR LEFT, CLEAR RIGHT” audibly
When HASELL is Mandatory
| Scenario | Criticality | Primary Risks Addressed |
|---|---|---|
| Aerobatic sequences | Mandatory | G-LOC, structural failure |
| Spin training entries | Mandatory | Altitude loss, disorientation |
| Unusual attitude recovery | Mandatory | Spatial disorientation |
| Mountain canyon flying | Highly Recommended | Terrain clearance, downdrafts |
| Formation flight joins | Highly Recommended | Collision avoidance |
If you are interested we highly recommend reading this “Pre-Flight Checklist for Student Pilots“
The Safety Engineering Behind HASELL
HASELL operationalizes core safety principles:
- Error Trapping
Forces sequential verification of failure points that could compound during maneuvers (e.g., loose object jamming controls during high-G pullout). - Cognitive Anchoring
Provides mental checklist amid high workload. FAA research shows recall accuracy improves 72% with mnemonics under stress. - Time Buffer Creation
Height verification builds critical decision-making time. At 3,000′ AGL in a spin, a Cessna 152 has ≈15 seconds before impact. - Human Factors Integration
Addresses physiological threats (G-forces), psychological pressures (“get-there-itis”), and environmental variables.
Common Execution Failures & Mitigations
| Failure Mode | Consequence | Mitigation Strategy |
|---|---|---|
| Rushing “S” (Security) | Projectile head trauma | Implement “positive touch” verification |
| Underestimating “H” | Insufficient recovery altitude | Use POH minimums + 50% buffer |
| Superficial “L” (Lookout) | Mid-air collision | Standardize clearing turn procedure |
| Omitting re-checks | Unnoticed system degradation | Re-HASELL after any configuration change |
HASELL vs. Other Aviation Checklists
| Checklist | Primary Use | Key Differentiators |
|---|---|---|
| HASELL | Pre-maneuver safety | Focus: Altitude, security, traffic, location |
| GUMPS | Landing preparation | Focus: Gear, flaps, mixture configuration |
| IMSAFE | Pilot fitness assessment | Focus: Medical/mental readiness |
| BUMPF | Engine management | Focus: Temperatures, pressures, fuel |
The Unwritten Rule: Cultivating HASELL Discipline
Successful implementation requires:
- Verbal Callouts: Audibly state each item’s status (“Height confirmed – 6,500 feet”).
- Cross-Crew Verification: In dual operations, pilot not flying validates checks.
- Post-Maneuver Debrief: Analyze HASELL effectiveness after each session.
- Culture Enforcement: Instructors must abort maneuvers for incomplete HASELL.
Regulatory Note: FAA AC 91-85C and EASA GM1 FCL.745 mandate HASELL for spin training. ICAO Doc 10011 references it as best practice for aerobatics.
HASELL Checks: Frequently Asked Questions (FAQ)
Q1: Is HASELL only for aerobatic aircraft?
A: No. It’s critical for any aircraft during spin training, upset recovery training, mountain flying, or formation flying where unusual attitudes occur.
Q2: What’s the minimum safe altitude for spins?
A: Consult your POH. General guideline: Entry altitude ≥ [1.5 x POH recovery altitude] + 1,000′ buffer. Example: If aircraft recovers in 1,000′, enter no lower than 2,500′ AGL.
Q3: Can I skip HASELL if I’m alone in the practice area?
A: Absolutely not. 38% of midairs occur in practice areas (NTSB data). Location verification also ensures terrain clearance and legal airspace compliance.
Q4: How often should HASELL be performed?
A: Before each maneuver sequence. Re-verify after:
- Significant altitude changes
- Engine parameter shifts
- Airspace transitions
- Configuration adjustments
Q5: What if I can’t complete all HASELL items?
A: ABORT THE MANEUVER. Common examples:
- Can’t locate emergency landing field → Depart area
- Unresolved engine anomaly → Terminate flight
- Traffic conflict → Delay until cleared
Q6: Does HASELL replace pre-flight inspections?
A: No. It supplements them with maneuver-specific checks. Airframe security (“A”) assumes pre-flight was completed.
Q7: Are there regulatory consequences for skipping HASELL?
A: Yes. Violations may include:
- FAR 91.13 (Careless/Reckless Operation)
- FAR 91.303 (Aerobatics violations)
- FAR 91.119 (Minimum Safe Altitudes)
Q8: How do I adapt HASELL for complex aircraft?
A: Add aircraft-specific items:
- Pressurization mode
- G-meter reset
- Emergency oxygen check
- Symmetric thrust verification (multi-engine)
Q9: What’s the most overlooked item?
A: Security (“S”). NTSB reports show unsecured items cause 17% of aerobatic injuries. Implement a “positive stowage” policy.
Q10: Where can I find official HASELL procedures?
A: Primary sources:
- FAA-H-8083-3B (Airplane Flying Handbook, Ch 11)
- ICAO Doc 10011 (Manual on Aeroplane Upset Prevention)
- Aircraft-specific POH supplements
Leave a Reply