Blood Donation, Diving, Vaccinations
Blood donation
A whole-blood donation removes 450–500 ml (~10 % of blood volume). Consequences: temporary haemoglobin drop and reduced oxygen-carrying capacity — relevant at altitude.
Recommendation: after whole-blood donation at least 24 h no flying, some sources require 48–72 h for PIC duty (FAA-H-8083-25B Chapter 17; AOPA Air Safety Foundation). Plasma donation has shorter recovery, nevertheless at least 12 h recommended.
EASA Part-MED contains no specific hour count, but refers via MED.A.020 to "decreased fitness perception".
SCUBA diving
While diving, N₂ dissolves into tissues under pressure. If the pilot ascends to lower pressure (flight) too soon, dissolved N₂ can form bubbles — altitude decompression sickness. See [[dekompressionskrankheit-bends]].
Wait times (FAA-H-8083-25B Chapter 17):
| Dive | Subsequent flight | Wait |
|---|---|---|
| No decompression stop, single | up to 8,000 ft cabin altitude | 12 h |
| Decompression stop or multiple dives | up to 8,000 ft | 24 h |
| Any dive | above 8,000 ft | 24 h |
Conservative recommendation: after any sport dive generally wait 24 h — Divers Alert Network (DAN), standard recommendation also for PPL.
Vaccinations
Acute side effects
Reactions like fever, fatigue, local swelling can last 24–48 h. Live vaccines (e.g. yellow fever, MMR) can cause stronger reactions.
Delayed reactions — important to note
A frequently underestimated phenomenon: vaccine reactions can also occur days after the vaccination — typically 3–10 days for some vaccines:
| Vaccine | Typical reaction window |
|---|---|
| Inactivated vaccines (influenza, tetanus, hepatitis B) | mostly 24–48 h, occasionally up to 7 days |
| Live vaccines (MMR, yellow fever, varicella) | reactions often only 5–14 days after vaccination (replication of attenuated virus) |
| mRNA / vector vaccines (COVID-19) | mostly 12–72 h, occasional later |
Delayed-reaction symptoms: fever, body aches, fatigue, rarely neurological symptoms.
Practical consequence: pilot should also monitor own state in the days after a vaccination (IMSAFE check before each flight). On symptomatic reaction: self-ground until symptoms fully resolved.
Recommendation (EASA AMC1 MED.A.020)
- After routine vaccinations observe at least 24 h.
- On symptoms self-ground until resolution.
- Live vaccines: possibly longer pause (5–14 days) — discuss with AME.
- Some vaccinations with long reaction duration (e.g. yellow fever, COVID-19 boosters) require individual AME consultation.