Rehearsals are where missions are refined, not where new risks should be introduced. Pilots and planners treat formation work and parade flypasts as high visibility events that demand tighter tolerances than routine operations. But tighter tolerances are not the same as increased tolerance for risk. Recent events in Malaysia underline that reality and show how a single unexpected event in a rehearsed profile can cascade into a serious accident.

On March 5 an AgustaWestland AW139 operated by the Malaysian Maritime Enforcement Agency made an emergency landing in the waters near Pulau Angsa during a training exercise. All four on board were rescued and the airframe was later recovered for investigation. That incident is a useful reminder that even well maintained, modern types can suffer problems during routine training that force immediate, high stress decision making.

Formation and multi‑ship rehearsal flying bring predictable hazards. Close lateral and vertical spacing reduces the margin for error, and when two or more helicopters operate in close proximity the opportunity for a small deviation to become a midair conflict goes up quickly. Malaysia has seen fatal and nonfatal midair collisions in the past, including a 2020 midair accident involving two light helicopters that killed occupants and left others injured, and the 2016 Eurocopter AS350 crash that claimed senior public officials. These events show the real consequences when errors, distractions or unexpected maneuvers occur near other aircraft.

From the cockpit perspective there are a handful of recurring causal factors I watch for in rehearsal profiles:

  • Task saturation during a complex maneuver. When pilots are concentrating on timing, formation geometry, and visual cues, their scan narrows and their ability to detect an aircraft encroaching from the blind sector can degrade rapidly.
  • Nonstandard or ad hoc join up procedures. If crews depend on last minute positioning, visual signals that are ambiguous, or inconsistent phraseology, the risk of misalignment increases.
  • Inadequate briefings and no abort criteria. A tight brief that does not define who calls the break off, or lacks explicit weather and spacing minima, leaves crews improvising under time pressure.
  • Operating over populated or constrained areas. Low altitude rehearsals over base infrastructure or sports facilities compress options for safe forced landings.

Military and civilian regulators recognise these hazards and set rules accordingly. Civil aviation authorities and police air operations manuals require formation flying to be prearranged, to occur within defined minima, and to be limited to conditions where crews can safely maintain visual separation. National guidance also restricts close formation in marginal weather or without the right approvals and training. These regulatory frameworks exist because the margin for error is small and because the consequences are large.

Practical mitigations that work in the real world are straightforward and repeatable. I would press the following if I were advising a navy on parade rehearsals:

  • Treat every rehearsal like a test item. Use the same brief, the same formation positions, and the same radio calls that will be used for the display. If any change is required, rehearse that change in isolation first.
  • Enforce strict go/no go criteria. Define minimum visibility, cloud bases, and wind limits in the brief. Name the single authority who can call the rehearsal off and empower them to do so without stigma.
  • Use a safety chase or observer aircraft. A dedicated platform outside the formation with an experienced safety observer can provide the early warning that formation pilots under high workload will miss.
  • Stage rehearsals away from hard downrange hazards. If a forced landing is needed, clear landing areas and rescue resources must be immediately available.
  • Standardise join up procedures and phraseology. Where possible, use instrument or electronic spacing tools to supplement the visual picture during close passes.
  • Maximise CRM and limit consecutive rehearsal cycles. Fatigue and complacency show up quickly in repetitive displays. Shorter, focused practice windows reduce rule bending.
  • Conduct a formal risk assessment and a written safety brief before the first formation flight each day. Include maintenance status and recent sorties for each airframe in the risk picture.

Technology can help but it is not a substitute for basic airmanship. Collision avoidance aids, datalinks, and synthetic training all reduce risk when implemented correctly. But formation flying still comes down to basic human tasks: see the other aircraft, maintain spacing, and be prepared to break off instantly. Systems that complicate the cockpit or give a false sense of security without changing crew behaviour will not prevent the common failure modes I have seen in the field.

Rehearsals are necessary. They are the best way to build the muscle memory crews need for public displays. But necessity must be balanced with conservatism. The recent MMEA AW139 rescue operation and the remembered history of midair collisions in the region are reminders that rehearsals carry non trivial risk. Planners, safety officers, and flight leads should treat rehearsals as an operational sortie with a formal risk control package, not a photo op with loose rules.

If your service runs formation rehearsals, keep the checklist, the brief, and the abort authority visible at all times. When we do that, we preserve the lives of crews and the reputation of the service. When we do not, the lessons are painful and permanent.